Infectious diseases of the skin

Question 1

1- Your mother calls you because she has a friend who came back from a wedding 3 days ago and has a red area on her leg. She says she may have had a bug bite but isn’t sure. It started as a red bump and it started to spread and is now about 6 cm, and almost target-like with redness on the outside and inside and a paler pink between. You recommend that she go to her doctor immediately. She has no medication allergies. What is the best course of action for the doctor?

A. Prescribe oral clarithromycin
B. Obtain IgG and IgM studies
C. Obtain urine antigen studies
D. Prescribe oral doxycycline
E. Admit the patient to the hospital for IV ceftriaxone

Answer 1

Correct choice: D. Prescribe oral doxycycline

Explanation: The patient most likely has erythema migrans, a cutaneous and early form of Lyme disease. The best course of action for classic cutaneous symptoms is treatment with oral doxycycline. Alternatives are only used in pregnancy or allergy. The other options highlight variable other testing for Lyme disease. The CDC recomends a 2-step testing procedure with an enzyme immunoassay or an indirect immunofluorescence assay followed, if positive, by an immunoblot test. IgG and IgM as well as urine antigen studies are not recommended. Oral clarithromycin and IV ceftriaxone are not appropriate in this case as the patient has no medication allergies and has early disease. Doxycycline is the perferred treatment.

Question 2

2- Which of the following is the most common treatment for sporotrichosis?

A. Supersaturated potassium iodide
B. Amphotericin B
C. Surgical excision
D. Cryotherapy
E. Itraconazole

Answer 2

Correct choice: E. Itraconazole

Explanation: Sporotrichosis (also known as “rose gardener’s disease”) is an infection caused by the fungus Sporothrix schenckii. Cutaneous (skin) infection is the most common form of the infection. It occurs when the fungus enters the skin through a small cut or scrape, usually after someone touches contaminated plant matter. Skin on the hands or arms is most commonly affected.
The first symptom of cutaneous sporotrichosis is usually a small, painless papule that can develop any time from 1 to 12 weeks after exposure to the fungus. The papule can be red, pink, or purple, and it usually appears on the finger, hand, or arm where the fungus has entered through a break in the skin. The papule will eventually grow larger and may look like an erosion or ulcer that is very slow to heal. Additional papules or ulcers may appear later near the original one.
The most common treatment for this type of sporotrichosis is itraconazole, taken by mouth for 3 to 6 months. Supersaturated potassium iodide (SSKI) is another treatment option for cutaneous sporotrichosis. For those with severe sporotrichosis that affects the lungs, bones, joints, or central nervous system, intravenous amphotericin B is the treatment of choice. After the first treatment with amphotericin B, patients may then receive itraconazole by mouth, for a total of at least 1 year of antifungal treatment. People with sporotrichosis in the lungs may also need surgery to cut away the infected tissue.

Question 3

3- A 30-year-old female presents complaining of thickened, yellowish, dystrophic toenails. On examination, you also notice maceration and scaling of the toe-web spaces and soles of the feet. You suspect she may have chronic tinea pedis and a dermatophyte infection of the nail unit. Which of the following is not a common causative pathogen of tinea unguium?

A. Trichophyton tonsurans
B. Trichophyton rubrum
C. Trichophyton interdigitale
D. Epidermophyton floccosum
E. Microsporum canis

Answer 3

Correct choice: E. Microsporum canis

Explanation: Tinea unguium refers specifically to dermatophyte infection of the nail unit. It occurs worldwide, affects men more often than women, and is frequently associated with chronic tinea pedis. Trauma and other nail disorders represent predisposing factors. Although all dermatophytes can cause tinea unguium, Microsporum spp. do so very rarely. The most common causative pathogens are T. rubrum, T. interdigitale, T. tonsurans (in children), and E. floccosum.

Question 4

4- What is the most likely diagnosis?

A. Syphilis
B. Gingival hypertrophy
C. Necrotizing periodontitis
D. Pyogenic stomatitis
E. Scurvy

Answer 4

Correct choice: C. Necrotizing periodontitis

Explanation: This is necrotizing periodontitis which is a marker of severe immunosuppression. Scurvy has bleeding gums, pyostomatitis vegetans is associated with IBD, gingival hypertrophy is a medication side effect commonly from cyclosporine.

Question 5

5- A 20-year-old man who recently returned from the Caribbean presents to your office with a painful penile ulcer and painful inguinal adenitis. A lesional swab for Gram stain shows a “school of fish” pattern. What is the most likely causative organism?

A. Herpes simplex virus
B. Treponema pallidum
C. Chlamydia trachomatis L1-3
D. Haemophilus ducreyi
E. Klebsiella granulomatis

Answer 5

Correct choice: D. Haemophilus ducreyi
Explanation: The stem describes the classic presentation of chancroid, a sexually-transmitted infection caused by the bacterium H. ducreyi. Worldwide, chancroid prevalence has declined, although infection might still occur in some regions of Africa and the Caribbean. Like genital herpes and syphilis, chancroid is a risk factor in the transmission and acquisition of HIV infection. A lesional swab sent for Gram stain classically shows the Gram-negative coccobacilli arranged in a “school of fish pattern.” Several effective treatment regimens exist, the most common being Azithromycin 1g orally in a single dose. The remaining listed organisms do not cause chancroid.

Question 6

6- A patient with AIDS developed purulent nodules and draining sinuses of the neck. Gram stain of pustular contents supports the diagnosis of which infectious organism?

A. Actinomyces israelii
B. Staphylococcal aureus
C. Pseudomonas aeruginosa
D. Mucor spp.
E. Blastomyces dermatitidis

Answer 6

Correct choice: A. Actinomyces israelii
Explanation: Actinomyces israelii are filamentous, gram-positive, and non-acid-fast bacteria that typically present as fluctuant nodules classically at the angle of the jaw (“lumpy jaw”) with fistulas and draining sinuses containing “sulfur granules”. IV Penicillin G is the initial treatment and should be used for 4-6 weeks. Oral Penicillin may be required afterwards for 2-12 months depending on severity of infection.

Question 7

7- A patient presents to your office with an ulcerated nodule with regional lymphadenopathy on his forearm. A culture of the ulcerated nodule grows Burkholderia mallei. The patient improves with doxycycline. When the patient asks why he developed this condition, you tell her this disease is caused by contact with which of the following?

A. Horses
B. Pigs
C. Sheep
D. Sphagnum moss
E. Dogs

Answer 7

Correct choice: A. Horses
Explanation: The patient in this clinical vignette has glanders caused by Burkholderia mallei. It is a disease caused by contact with infected horses. The characteristic features consist of an ulcerated nodule with regional lymphadenopathy. Treatment options include imipenem or doxycycline or sulfadiazine.

Question 8

8- What is the most likely diagnosis?

A. Acute paronychia
B. Onychomycosis
C. Herpetic whitlow
D. Orf
E. Disseminated gonococcal infection

Answer 8

Correct choice: C. Herpetic whitlow
Explanation: This is an image of herpetic whitlow, which is typified by grouped vesicles on an erythematous base occurring on the finger(s). Herpetic whitlow is caused by herpes simplex virus (type 1 or 2) during primary infection or as result of autoinoculation. Commonly, it is caused by HSV-2 in adults with positive history for genital infection.
The other answer choices do not present with grouped vesicles on an erythematous base.

Question 9

9- These nail findings are most likely due to infection with which organism?

A. Trichophyton tonsurans
B. Trichophyton mentagrophytes
C. Trichophyton rubrum
D. Trichophyton verrucosum
E. Trichophyton schoenleinii

Answer 9

Correct choice: C. Trichophyton rubrum
Explanation: The image displays the clinical features of onychomycosis. T. rubrum is the most common cause of onychomycosis in the US. The remaining listed dermatophytes do not cause onychomycosis as often as T. rubrum.

Question 10

10- A infectious pustular dermatitis develops in a goat farmer. The causative organism is known to be very sturdy and survives many months in the cold winter. There is localized lymphadenopathy and crusting. The most likely etiologic organism is:

A. Sporothrix schenckii
B. Francisella tularensis
C. Parapox virus
D. Erysipelothrix rhusiopathiae
E. Orthopox virus

Answer 10

Correct choice: C. Parapox virus
Explanation: This describes Orf. It is also known as ecthyma contagiosum or contagious pustular dermatosis. It is transmitted to humans by a parapoxvirus in sheep, goats, and reindeer. It is self- limited with an excellent prognosis, thus treatment is supportive. Sporothrix schenckii causes sporotrichosis, a fungal infection associated with inoculation via rose thorns. Tularemia, which is associated with rabbit contact, is caused by the bacterium Francisella tularensis. Erysipelothrix rhusiopathiae, the causative agent of erysipeloid, is a bacterium that is transmitted via pigs or fish. Orthopox viruses can cause vaccinia, smallpox, or cowpox.

Question 11

11- Which of the following is FALSE regarding actinomycosis?

A. Poor dental hygiene is a risk factor
B. It most often develops on the jawline
C. It is caused by an anaerobic filamentous Gram-negative bacterium
D. Drainage of yellow sulfur-like granules is characteristic
E. The treatment of choice is penicillin

Answer 11

Correct choice: C. It is caused by an anaerobic filamentous Gram-negative bacterium
Explanation: Actinomyces israelii, the causative agent of actinomycosis, is an anaerobic filamentous Gram-positive bacterium that is part of the normal oral flora. The other remaining answer choices are true.

Question 12

12- A 4-year-old female presents with three warts on the right hand for two months. Her mother tried apple cider vinegar and Mr. Freeze, neither of which helped. What is the next best approach?

A. Cryotherapy x 10 seconds a 2 cycles to all three lesions, use topical salicylic acid at home as directed

B. Inject 0.3 cc Candida antigen into two of the warts after cleaning them with rubbing alcohol pad
C. Excision
D. Electrofulguration
E. Use imiquimod cream Monday, Wednesday, and Friday to each wart under occlusion

Answer 12

Correct choice: A. Cryotherapy x 10 seconds a 2 cycles to all three lesions, use topical salicylic acid at home as directed.
Explanation: Cryotherapy is the next most reasonable step for this patient with warts. While several of the alternative modalities might be tried in the future, the most reasonable next step is to perform cryotherapy to each wart after obtaining consent from the parent.

Question 13

13- Which of the following is a reasonable first-line treatment for the disease caused by Bartonella bacilliformis and spread by the Lutzomyia sandfly?

A. Ciprofloxacin
B. Vancomycin
C. Clindamycin
D. Imipenem
E. Streptomycin

Answer 13

Correct choice: A. Ciprofloxacin
Explanation: Oroya Fever (Carrion’s Disease) is caused by Bartonella bacilliformis. The Lutzomyia sandly is the vector. Multiple antimicrobial agents are active against B. bacilliformis in vitro, including fluoroquinolones, chloramphenicol, doxycycline, and rifampin. Ciprofloxacin is a reasonable first-line treatment, although resistance is increasing. Therefore, many favor a combination of ciprofloxacin and ceftriaxone. Previously, chloramphenicol was the preferred agent, as it has activity against Salmonella as well, a common secondary infection. However, treatment failure has been described with chloramphenicol. In addition treatment of Oroya fever with chloramphenicol does not eliminate risk for development of verruga peruana. The other choices are not considered good treatment options against this organism since relatively high dosease are required to inhibit bacterial growth.

Question 14

14- A patient presents with yellowish brown concretions on axillary hair shafts bilaterally. Which of the following non-medical management advice can the patient follow to improve this condition?

A. Avoidance of shaving
B. Shaving
C. Switching to unscented, fragrance-free deodorant
D. Avoiding deodorant
E. Avoid participation in athletics

Answer 14

Correct choice: B. Shaving
Explanation: Trichomycosis axillaris is caused by Corynebacterium tenuis. It is characterized by yellowish brown concretions on axillary hair shafts. Treatment options include shaving, benzoyl peroxide gel, topical erythromycin.

Question 15

15- A 7-year-old boy presents to your clinic with his mother, who tells you the boy has been having multiple days of flu-like symptoms and a new rash that is asymptomatic. On exam you notice a 5cm erythematous annular patch on his thigh. Both the boy and his mother deny a history of a tick or other insect bite. What is the best treatment?

A. None; this condition is self-resolving
B. Doxycycline
C. IV ceftriaxone
D. Trimethoprim-sulfamethoxazole
E. Amoxicillin

Answer 15

Correct choice: E. Amoxicillin
Explanation: The stem describes a classic presentation of early localized Lyme disease, which commonly does not include a positive history of a tick bite. This diagnosis can be made clinically when erythema chronicum migrans (expanding annular erythematous patch at the site of tick bite) is noted on exam as this is pathognomonic. As such, starting antibiotic treatment is warranted to prevent progression of the disease into the early disseminated or chronic stages. In pregnant women and children <8 years old, amoxiciliin for 14-21 days is used due to concern for potential bone and tooth abnormalities induced by tetracycline-class antibiotics. Lyme disease is not self-resolving (although erythema chronicum migrans usually disappears within 4 weeks without treatment) and requires antibiotic treatment to prevent disease progression and its associated morbidity. For adults

and children > 8 years old, doxycycline for 14-21 days is the treatment of choice. The other answer choices are distractors.

Question 16

16- A 3-year-old girl is brought into clinic by her father, who reports that she has an itchy rash on the scalp. On exam, you notice a large oval erythematous scaly thin plaque. Wood’s light examination of the lesion demonstrates fluorescence. What is the most likely causative organism?

A. Trichophyton tonsurans
B. Microsporum nanum
C. Trichophyton rubrum
D. Candida albicans
E. Microsporum canis

Answer 16

Correct choice: E. Microsporum canis
Explanation: The question stems describes a case of fluorescent tinea capitis, which is most often due to infection with M. canis. T. tonsurans is the most common cause of tinea capitis in North America, however this is an endothrix infection and thus does not demonstrate fluorescence with Wood’s light examination. T. rubrum and M. nanum rarely produce non-fluorescent ectothrix tinea capitis. Candida albicans does not cause tinea capitis.

Question 17

17- A 19-year-old military recruit presents to the dermatology office with intensely pruritic papules on the trunk and genital region. A papule is scraped with a #15 blade and immersed in mineral oil. The following image is seen on microscopy. What is the most likely diagnosis?

A. Tinea corporis
B. Tinea versicolor
C. Pityrosporum folliculitis
D. Scabies
E. Cheyletiellosis

Answer 17

Correct choice: D. Scabies

Explanation: The above image shows scabetic scybala (fecal pellets). The diagnosis can be confirmed through the detection of scabies mites, eggs or feces with a mineral oil prep.
Tinea corporis on KOH prep will show segmented hyphae. Tinea versicolor and pityrosporum folliculitis will show both hyphae and yeast cells on KOH. Cheyletiellosis, also referred to as “walking dandruff”, are nonburrowing mites commonly found on rabbits, dogs, and cats. The mites have been known to cause disease in humans, ranging from mild dermatitis to more severe illness with systemic symptoms. Because these mites do not complete any part of their life cycle in humans, diagnosis can be challenging and one is unlikely to find these findings on a skin scraping.

Question 18

18- You are called for an emergent consult in a patient with exquisite tenderness, erythema, warmth and swelling that does not respond to antibiotics. The skin appears shiny and tense. The patient complains of pain out of proportion to skin findings. Within 36 hours the skin changes from reddish in color to a grayish-blue color in ill-defined patches. You notice a thin, watery, malodorous fluid. An x-ray of her forearm (pictured) shows the presence of gas in the soft tissues. Which of the following risk factors is NOT associated with higher mortality in this life-threatening condition?

A. Diabetes mellitus
B. Elevated lactic acid level
C. Elevated serum creatinine
D. Delay to first debridement
E. Disease due to Staphylococcus aureus

Answer 18

Correct choice: E. Disease due to Staphylococcus aureus
Explanation: Necrotizing fasciitis is characterized by rapidly progressive necrosis of subcutaneous fat and fascia, which can be life-threatening without prompt recognition, aggressive surgical intervention and immediate antibiotic therapy. Higher mortality is associated with female sex, older age, malnutrition, greater extent of infection, delay to first debridement, an elevated serum creatinine or lactic acid levels, disease due to group A streptococci, and a greater degree of organ dysfunction at the time of admission to hospital. Diabetes mellitus can also result in higher mortality, particularly if renal dysfunction or peripheral arterial disease is also present.
1 –Diabetes can also result in a higher mortality in necrotizing fasciitis, particularly if renal dysfunction or peripheral arterial disease is also present. 2 – Higher mortality in necrotizing fasciitis is associated with female sex, older age, malnutrition, greater extent of infection, delay to first debridement, an elevated serum creatinine or lactic acid level, disease due to group A streptococci, and greater degree of organ dysfunction at the time of admission to hospital. 3 – Higher mortality in necrotizing fasciitis is associated with female sex, older age, malnutrition, greater extent of infection, delay to first debridement, an elevated serum creatinine or lactic acid level, disease due to group A streptococci, and greater degree of organ dysfunction at the time of admission to hospital. 4
- Higher mortality in necrotizing fasciitis is associated with female sex, older age, malnutrition, greater extent of infection, delay to first debridement, an elevated serum creatinine or lactic acid level, disease due to group A streptococci, and greater degree of organ dysfunction at the time of admission to hospital.

Question 19

19- This patient has a cat. What is the etiology of her findings?

A. Borrellia recurrentis
B. Bartonella quintana
C. Bartonella bacilliformis
D. Borrellia burgdoferi
E. Bartonella henselae

Answer 19

Correct choice: E. Bartonella henselae
Explanation: This is submental lymphadenopathy secondary to cat scratch disease due to bartonella henselae. It is one of the most common causes of chronic lymphadenopathy in children. B. quintana causes bacillary angiomatosis and trench fever. B. Bacilliformis causes oroya fever/verruga peruana. B. Burgdorferi causes lyme disease and B. recurrentis causes relapsing fever.

Question 20

20- Which of the following is the most appropriate treatment of this infant’s painful finger?

A. Incision and drainage
B. Acyclovir
C. Foscarnet
D. Dicloxacillin
E. Clindamycin

Answer 20

Correct choice: B. Acyclovir
Explanation: The most appropriate treatment of herpetic whitlow is acyclovir.
This question requires the examinee to clinically identify herpetic whitlow by the presence of clustered vesicles with surrounding erythema and edema located on a distal digit. Herpetic whitlow, caused by direct inoculation of the digital pulp by herpes simplex virus (HSV) 1 or 2, should be treated with acyclovir (choice 2). Incision and drainage (choice 1) may be required to treat a digital pulp abscess (felon), which would manifest with an erythematous fluctuant nodule lacking clustered vesicles. Foscarnet (choice 3) is used to treat acyclovir-resistant HSV infections, which typically occur in immunosuppressed patients. Dicloxacillin (choice 4) treats streptococcal and staphylococcal infections. On the differential diagnosis for herpetic whitlow is blistering distal dactylitis, usually caused by group A Streptococcus and appropriately treated with dicloxacillin. However, blistering distal dactylitis presents with a single vesicle or bulla, rather than clustered vesicles, at the palmar fingertip. Clindamycin (choice 5) is used to treat methicillin-resistant Staphylococcus aureus infections as well as bacterial toxin-mediated diseases (staphylococcal scalded skin syndrome, toxic shock syndrome), which would not present with clustered vesicles on a digit.

Question 21

21 -Clinically, actinomycotic mycetoma and eumycotic mycetoma appear identical. The importance of identifying the etiologic agent is

A. Academic
B. Selecting the appropriate therapy
C. Ordering appropriate stains
D. Determine if the infection is contagious
E. Determine if amputation is necessary

Answer 21

Correct choice: B. Selecting the appropriate therapy
Explanation: The etiologic agents of actinomycotic mycetoma are filamentous bacteria that require antibiotics, whereas fungal agents causing eumycotic mycetoma require antifungal therapy. The other answer choices are not as important as selecting the correct treatment option for patients with mycetoma.

Question 22

22- Which of the following are treatment options for a patient who presents with malodor, hyperhidrosis, shallow pits on the plantar surfaces of both feet?

A. Topical erythromycin
B. Topical clindamycin
C. Benzoyl peroxide
D. Doxycycline
E. Choice A, B and C are correct

Answer 22

Correct choice: E. Choice A, B and C are correct
Explanation: Pitted keratolysis is caused by Kytococcus sedentarius (formerly Micrococcus sedentarius). It is characterized by 1-3 mm pits on plantar surfaces of both feet, malodor and hyperhidrosis. Treatments include topical erythromycin, clindamycin, or benzoyl peroxide. Oral treatment is not indicated for this condition.

Question 23

23- Which bacteria is responsible for these findings?

A. Staphylococcus aureus
B. Kytococcus sedentarius
C. Actinomyces israelii
D. Pseudomonas aeruginosa
E. Corynebacterium tenuis

Answer 23

Correct choice: E. Corynebacterium tenuis
Explanation: Trichomycosis axillaris is caused by Corynebacterium (mostly Corynebacterium tenuis). Erythrasma is caused by Corynebacterium minutissimum, and its coral-red fluorescence is caused by production of coproporphyrin III by the organisms.

Question 24

24- Sensation is intact in this lesion, but a Fite stain is positive. This lesions is associated with which of the following:

A. IL-2
B. IL-4
C. IL-12
D. IL-15
E. IL-18

Answer 24

Correct choice: B. IL-4
Explanation: The lesion is low immune or lepromatous leprosy, which is associated with TH2 cytokines including IL-4, IL-5, IL-10, and IL-13. Tuberculoid leprosy is associated with Th1 cytokines including IFN-gamma, IL2, IL12, IL15, IL18 and IL23.

Question 25

25- A goat farmer presents with fever and flu-like symptoms, as well as violaceous papulonodules on the trunk and lower extremities. You consider Malta fever in your differential diagnosis. Which of the following statements regarding this diagnosis is correct?

A. Treatment is with doxycycline
B. Treatment is with ciprofloxacin
C. Skin lesions are frequently seen
D. Caused by a gram positive rod
E. Occurs frequently in the US

Answer 25

Correct choice: A. Treatment is with doxycycline

Explanation: Treatment of malta fever is with doxycycline or rifampin. Malta fever is another name for Brucellosis. This infection is caused by ingesting raw goat milk and unpasteurized goat cheese infected with Brucellae (gram-negative rods). It is infrequent in the US, occurring mainly in veterinarians and farmers. Acute brucellosis has very non-specific features and presents as a flu-like illness. Skin lesions are infrequent (20% of cases) but are usually violaceous papulonodules on the trunk and lower extremities.

Question 26

26- Brucellosis is typically associated with which of the following routes of transmission?

A. Contact with rabbits
B. Ingestion of raw seafood
C. Flea bite from infected animal
D. Inhalation of aerosolized bird excretions
E. Ingestion of unpasteurized dairy products

Answer 26

Correct choice: E. Ingestion of unpasteurized dairy products
Explanation: Brucellosis (aka Undulant fever; Malta fever) is caused by the gram-negative bacterium Brucella spp. It is typically contracted via direct contact with an infected animal (undulant) or ingestion of infected meat or unpastuerized dairy products. Butchers, farmers, veterinarians, and unwise tourists are at highest risk. Clinical findings include: cyclic fevers, arthralgias, hepatosplenomegaly, rare skin involvement with a violaceous papulonodular eruption, and/or endocarditis (most common cause of death). The treatment of choice is doxycycline combined with rifampin. The remaining answer choices have the following disease associations: Contact with rabbits-Tularemia, Ingestion of raw seafood- Vibrio infection, Flea bite from infected animal- Plague ,Inhalation of aerosolized bird excretions- Psittacosis.

Question 27

27- What is the treatment for secondary syphilis in a penicillin allergic patient?

A. Penicillin
B. Doxcycyline
C. Rifampiin
D. Clindamycin
E. Ceftriaxone

Answer 27

Correct choice: B. Doxcycyline
Explanation: Secondary syphillis is caused by the spirochete, T. pallidum. Penicillin is the treatment of choice for secondary syphillis. In penicillin allergic individuals, doxycyline may be used. Treatment for neurosyphilis, congenital syphilis and syphilis in pregnant women is desensitization to penicillin and then treatment with pcn.

Question 28

28- A 20-year-old man developed edematous, pink to red follicular papules and pustules primarily on the trunk while on vacation. He remembers being in the jacuzzi about 12 hours prior to the onset of his rash. The lesions are itchy. After 3 weeks, the lesions resolve spontaneously. Which of the following organisms is most likely responsible for this patient’s initial skin condition?

A. Staphylococcus aureus
B. Streptococcus pyogenes
C. Proteus mirabilis
D. Pseudomonas aeruginosa
E. Escherichia coli

Answer 28

Correct choice: D. Pseudomonas aeruginosa
Explanation: Hot tube folliculitis is due to Pseudomonas aeruginosa in the setting of use of a hot tub/whirlpool 12-48 hours prior to onset. It is characterized by edematous, pik to red follicular papules and pustules, primarily on the trunk. It is often pruritic and resolve sspontaneously in immunocompetent hosts. It my be a serious illness in immunocompromised hosts. The condition is generally self-limited - patients can use antibacterial soap. If severe or immunocompromised, patient can take ciprofloxacin for 7-14 days. The water in the hot tub, whirpool or swimming pool must be maintained with chlorine and changed every 6-8 weeks to lower organic carbon level.

Question 29

29- What is the etiologic agent for this lesion?

A. Pox virus
B. Herpes virus
C. Human papilloma virus
D. Togavirus
E. Coxsackie virus

Answer 29

Correct choice: A. Pox virus
Explanation: This is molluscum contagiosum which is due to a pox virus.

Question 30

30- This organism causes a resistant tinea pedis that is clinically indistinguishable from dermatophytosis:

A. Aspergillus flavus
B. Scytalidium dimidiatum
C. Curvularia sp.
D. Scopulariopsis
E. Fonsecaea sp

Answer 30

Correct choice: B. Scytalidium dimidiatum
Explanation: Scytalidium dimidiatum is a non-dermatophyte cause of tinea pedis that is very difficult to treat due to its resistance to most antifungals. It is sensitive to cylcoheximide so it should be cultured on media free of this antifungal.

Question 31

31- A woman who handles fish tanks develops a slow-growing cluster of papules on the hand. Which antibiotic is a reasonable single-drug approach to treatment?

A. Isoniazid
B. Clarithromycin
C. Rifampin
D. Penicillin
E. Dapsone

Answer 31

Correct choice: B. Clarithromycin
Explanation: This patient most likely has contract Mycobacterium marinum, otherwise known as “fish tank granuloma.” A reasonable approach to treatment of M. marinum consists of treatment with two antibiotics for one to two months after resolution of symptoms. One approach consists of clarithromycin combined with ethambutol OR rifampin. For minimal disease, some favor single- drug therapy with clarithromycin, minocycline or doxycline. The other antibiotic choices are not considered first-line for single-drug therapy.

Question 32

32- What characteristic color is seen on diascopy of this infectious lesion?

A. Apple jelly
B. Blue
C. Orange
D. Red
E. Coral red

Answer 32

Correct choice: A. Apple jelly
Explanation: Leishmaniasis recidivans is a type of Old World leishmaniasis. Clinically, it appears as a red papule covered with white scale. On diascopy, it has a characteristic apple jelly color. The other listed colors are not seen on diascopy of leishmaniasis.

Question 33

33- The most common cause of tinea capitis in the United States today is:

A. Trichophyton schoenleinii
B. T. tonsurans
C. T. mentagrophytes
D. Microsporum audouinii
E. M. canis

Answer 33

Correct choice: B. T. tonsurans

Explanation: T. tonsurans is currently the primary cause of tinea capitis in the US.
None of the remaining listed answers is the most common current cause of tinea capitis (M. audouinii was previously the primary cause of tinea capitis in the US).

Question 34

34- This lesion is hypoesthetic and is associated with which of the following:

A. Interleukin 2
B. Interleukin 4
C. Interleukin 5
D. Interleukin 10
E. Interleukin 13

Answer 34

Correct choice: A. Interleukin 2

Explanation: The lesion is high immune or tuberculoid leprosy, which is associated with Th1 cytokines including IFN-gamma, IL2, IL12, IL15, IL18 and IL23. Lepromatous leprosy is associated with Th2 cytokines including IL4, 5, 10 and 13.

Question 35

35- What organism caused this disease?

A. Kytococcus sedentarius
B. Candida albicans
C. Staphylococcus aureus
D. Corynebacterium tenuis
E. Corynebacterium diptheria

Answer 35

Correct choice: A. Kytococcus sedentarius
Explanation: Pitted keratolysis is a skin disorder characterized by crateriform pitting that primarily affects the pressure-bearing aspects of the plantar surface of the feet. It is caused by a cutaneous infection with micrococcus sedentarius which is included in the Corynebacteria genus. These are gram-positive, catalase-positive, aerobic or facultatively anaerobic, generally nonmotile rods. Corynebacterium diphtheriae infection is classically characterized by a local inflammation, usually in the upper respiratory tract, associated with toxin-mediated cardiac and neural disease. Corynebacterium tenuis causes trichomycosis Patients typically present with yellow, black, or red pinpoint nodules on the hair shafts in the inguinal region. Staphylococcus aureus is a common bacterium that can result in formation of pustules, furuncles, cellulitis and abscesses. Candida species are responsible for superficial infections such as oropharyngeal candidiasis (thrush) and vulvovaginal candidiasis (vaginal Candidiasis) and is also occurs as an opportunistic infection The other associated organisms do not cause pitted keratolysis.

Question 36

36- Trichomycosis axillaris is caused by:

A. Burkholderia mallei
B. Proteus species
C. Corynebacterium tenuis
D. Micrococcus sedentarius
E. Corynebacterium minitissimum

Answer 36

Correct choice: C. Corynebacterium tenuis

Explanation: Corynebacterium tenuis is the causative organism associated with most cases. Although up to 33% of adults have colonization by this bacterium in the inguinal or axillary regions, factors such as hyperhidrosis predispose to more extensive growth and resultant clinical manifestations. The other answer choices listed are incorrect.

Question 37

37- This Nigerian patient tells you that he is a farmer. Which of the following is the most likely causative organism?

A. M. marinum
B. M. tuberculosis
C. M. kansasii
D. M. ulcerans
E. M. fortuitum

Answer 37

Correct choice: D. M. ulcerans
Explanation: The image depicts a Buruli ulcer, which is due to infection with Mycobacterium ulcerans. Buruli ulcer is a neglected tropical disease of skin and subcutaneous tissue that can result in long-term cosmetic and functional disability. It is a geographically restricted infection but transmission has been reported in endemic areas in more than 30 countries worldwide. The heaviest burden of disease lies in West and Sub-Saharan Africa where it affects children and adults in subsistence agricultural communities. Mycobacterium ulcerans infection is probably acquired via inoculation of the skin either directly from the environment or indirectly via insect bites. The environmental reservoir and exact route of transmission are not completely understood. Treatments include excision, local heating (as mycobacteria prefer cooler temperatures); drug therapy is often disappointing. The other mycobacteria are not the most common cause of a Buruli ulcer.

Question 38

38- Which of the following is true about this condition?

A. Histology will show amastagotes in plasma cells
B. Culture is performed on MacConkey agar
C. Diagnosis may be made by sending a sample for real-time PCR assay to the Centers for Disease Control and Prevention
D. This condition does not typically resolve without treatment
E. Organisms are evenly spaced and surrounded by a pseudocapsule

Answer 38

Correct choice: C. Diagnosis may be made by sending a sample for real-time PCR assay to the Centers for Disease Control and Prevention.
Explanation: This is cutaneous leishmaniasis. Amastagotes are seen in dermal macrophages. Leishmaniais grows on Nicolle-Novy-MacNeal media or chick embryo media. The CDC does complimentary diagnoses for leishmaniasis with PCR. Old World cutaneous leishmaniasis and New World leishmaniasis typically resolves without treatment, but is treated to minimize scarring and prevent dissemination. The treatment of choice is parenteral pentavalent antimonials for cutaneous and mucocutaneous forms, while liposomal amphotericine B is used for visceral leishmaniasis. Leishmaniasis organisms often line up at periphery of vacuole without forming any surrounding pseudocapsules in contrast to histoplasma infection with evenly spaced organisms, that are surrounded by a pseudocapsule.

Question 39

39- The treatment of choice for Oroya Fever is:

A. Penicillin
B. Doxycycline
C. Erythromycin
D. Minocycline
E. Ciprofloxacin

Answer 39

Correct choice: E. Ciprofloxacin
Explanation: Oroya Fever (Carrion’s Disease) is caused by Bartonella bacilliformis. The Lutzomyia sandly is the vector. Multiple antimicrobial agents are active against B. bacilliformis in vitro, including fluoroquinolones, chloramphenicol, doxycycline, and rifampin. Ciprofloxacin is a reasonable first-line treatment, although resistance is increasing. Therefore, many favor a combination of ciprofloxacin and ceftriaxone. Previously, chloramphenicol was the preferred agent, as it has activity against Salmonella as well, a common secondary infection. However, treatment failure has been described with chloramphenicol. In addition treatment of Oroya fever with chloramphenicol does not eliminate risk for development of verruga peruana. The other answer choices are not the current choice of antibiotics for Oroya Fever.

Question 40

40- An immunosuppressed patient with a history of a renal transplant develops folliculocentric facial spicules (see photo). A virus was detected. What is the most likely causative organism?

A. Merkel cell polyomavirus (MCPyV)
B. HSV
C. HPV
D. Trichodysplasia spinulosa-associated polyoma virus (TSPyV)
E. VZV

Answer 40

Correct choice: D. Trichodysplasia spinulosa-associated polyoma virus (TSPyV)
Explanation: She has trichodysplasia spinulosa which is seen in settings of immunosuppression. Recently, TSV has been identified as the causative agent.

Question 41

41- Which of the following is most closely associated with Staphylococcus aureus?

A. Chronic paronychia
B. Bullous impetigo
C. Bullous cellulitis
D. Blistering distal dactylitis
E. Ecthyma

Answer 41

Correct choice: B. Bullous impetigo

Explanation: Bullous impetigo is caused by phage group II Staphylococcus aureus. This question tests the examinee’s knowledge of bacterial infections and in particular those caused by S. aureus.

Of the answer choices, bullous impetigo (choice 2) is most closely associated with S. aureus infection. In bullous impetigo, phage group II S. aureus produces exfoliatoxins A/B which cleave desmoglein 1, leading to bulla formation. In contrast to acute paronychia, which is commonly caused by S. aureus, chronic paronychia (choice 1) is related more to chronic irritant/allergic contact dermatitis than infection. Most cases of cellulitis (choice 3), bullous or otherwise, are not cultured, but it is generally considered to be caused more often by streptococci than staphylococci. Blistering distal dactylitis (choice 4) and ecthyma (choice 5) are most commonly caused by Streptococcus pyogenes.

Question 42

42- A 34-year-old male presents to clinic for evaluation of a scaly eruption of the bilateral groins for the past 6 months. His primary care physician has prescribed topical terbinafine, topical hydrocortisone, and topical triamcinolone, each of which demonstrated no benefit after a one month trial. A Wood’s lamp exam demonstrated coral red fluorescence within the eruption. What organism is responsible for this condition?

A. Corynebacterium minutissimum
B. Trichophyton Rubrum
C. Malassezia furfur
D. Kytococcus sedentarius
E. Trueperella pyogenes

Answer 42

Correct choice: A. Corynebacterium minutissimum

Explanation: Choice 1, corynebacterium minutissimum, is the causative agent in erythrasma, which is the described condition. Coral-red fluorescence with Wood’s light is attributable to coproporphyrin III, produced by the bacterium. Trichophyton rubrum is a dermatophyte, which would respond well to topical terbinafine. Malassezia furfur is the yeast implicated in Pityriasis Versicolor. Kytococcus sedentarius is a bacterium which is often associated with pitted keratolysis.

Question 43

43- A 54 year old male with recent weight loss develops disseminated flesh-colored large papules with central umbilication. A diagnosis of molluscum contagiosum is made. Which of the following conditions should be considered testing for?

A. HIV status

B. Hepatitis C status
C. Diabetes mellitus
D. Familial hypercholesterolemia
E. Porphyria cutanea tarda

Answer 43

Correct choice: A. HIV status
Explanation: Molluscum contagiosum can occur in the setting of immunodeficiency, including in patients with HIV or following treatment with immunosuppressive drugs. In immunocompromised patients, lesions can be large and widespread. Since the introduction of potent antiretroviral therapy, the number of molluscum cases in HIV patients has decreased substantially.
Patient with extensive lesions should be tested for HIV infection and the possibility of other immune system disorders also can be considered. The other conditions are not as strongly associated with large, disseminated molluscum lesions.

Question 44

44- A 28-year-old male presents with follicular pustules on the upper trunk and mid-chest. Many of the lesions are arising on an erythematous base. On exam, you notice the eruption favors areas with terminal hairs and is also present on the scalp and beard, buttocks and lower extremities. You suspect he may have superficial folliculitis. What is the most common cause of this condition which would be revealed on bacterial culture of pustular contents?

A. Normal flora
B. Staphylococcus aureus
C. Streptococcus
D. Pseudomonas aeruginosa
E. Group B streptococcus

Answer 44

Correct choice: A. Normal flora
Explanation:Superficial folliculitis is characterized by follicular pustules, often arising on an erythematous base. It favors areas with terminal hairs, such as the scalp and beard, as well as the upper trunk, buttocks, and lower extremities. Bacterial culture of pustular contents most commonly reveals normal flora, followed by Staphylococcus aureus.

Question 45

45- This disorder is linked to an abnormality in which of the following intercellular proteins?

A. Desmoplakin
B. Desmocollin 1
C. Desmoglein 1
D. Desmoglein 3
E. Desmoglein 4

Answer 45

Correct choice: C. Desmoglein 1
Explanation: In staphylococcal scalded skin syndrome (SSSS), phage group II Staphyloccocus aureus produces toxins that cleave desmoglein 1.
This question presents the examinee with an image depicting the highly characteristic periorificial radial crusting and fissuring of SSSS, and assesses knowledge of disease pathomechanism. In SSSS, phage group II Staphyloccocus aureus produces exfoliatoxins (epidermolytic toxins) A and B, which disseminate hematogenously to cleave desmoglein 1 (choice 3), leading to desmosomal splitting, granular layer disruption, and formation of superficial bullae. Desmoplakin (choice 1) is mutated in Carvajal syndrome, which consists of striate palmoplantar keratoderma, woolly hair, and left-sided cardiomyopathy. Desmocollin 1 (choice 2) is the target antigen in the subcorneal pustular dermatosis type of IgA pemphigus. Autoantibodies to desmoglein 3 (choice 4) are formed in pemphigus vulgaris. Mutations in desmoglein 4 (choice 5) occur in autosomal recessive monilethrix and localized autosomal recessive hypotrichosis.

Question 46

46- A new patient complains of persistent itchy hand and foot rashes not responding to changing soaps, minimizing hand washing, and using an over-the-counter topical steroid. Which of the following is the most appropriate next step in management?

A. High-potency topical steroid under occlusion

B. Phototherapy
C. Skin biopsy
D. Patch testing
E. Potassium hydroxide preparation

Answer 46

Correct choice: E. Potassium hydroxide preparation

Explanation: A potassium hydroxide (KOH) preparation should be performed to diagnose tinea manuum/pedis presenting as the “two feet-one hand syndrome.”

This question requires the examinee to identify the “two feet-one hand syndrome” of tinea manuum/ pedis. In the photo only the left hand shows powdery white scale favoring the palmar creases, and there is moccasin scale of the visible sole. Thus, the next best step in management is to perform a KOH preparation (choice 5) to make the diagnosis of dermatophytosis. Although hand dermatitis is included in the differential, in this scenario it would be inappropriate to start a high-potency topical steroid under occlusion (choice 1) or phototherapy (choice 2) prior to ruling out dermatophytosis. A skin biopsy (choice 3) is not required when KOH, a simple in-office procedure, will suffice to make the correct diagnosis. Patch testing (choice 4) for persistent hand dermatitis helps to rule out allergic contact dermatitis, but in this clinical scenario a KOH preparation should be performed first.

Question 47

47- A 33-year-old African-American HIV-infected male presents with marked pruritic follicular papules, urticarial and pustular that favor the face, scalp, upper trunk, and upper arms which has been present for months. A biopsy showed lesions characterized by spongiosis and exocytosis of eosinophils and lymphocytes into the follicular epithelium. You tell him treatment of the underlying viral infection with a resultant rise in CD4 cell count may lead to a resolution of lesions. At what CD4 count does this dermatology condition occur in HIV-infected patients?

A. 50
B. 100
C. 200
D. 400
E. 1000

Answer 47

Correct choice: C. 200

Explanation: Eosinophilic folliculitis is characterized by markedly pruritic follicular papules, urticarial and/or pustular, that favor the face, scalp, and upper trunk. It occurs in the setting of immunosuppression, including from HIV infection and following allogeneic hematopoietic stem cell transplantation. In HIV-infected patients, the CD4 count is usually <200 cells/mm3; it may also be a manifestation of IRIS (immune reconstitution inflammatory syndrome). Histologically, lesions are characterized by spongiosis and exocytosis of eosinophils and lymphocytes into the follicular epithelium. In HIV-infected patients, the CD4 count in patients with eosinophilic folliculitis is usually <200 cells/mm3; it may also be a manifestation of IRIS (immune reconstitution inflammatory syndrome).

Question 48

48- A Brazilian man presents to your office with a chronic ulcer of his right nasal ala. Biopsy reveals histiocytes containing small oval organisms with bar shaped paranuclear kinetoplasts. What is the best treatment for this condition?

A. Amphotericin B
B. Fluconazole
C. Surgical excision
D. Ivermectin
E. Sodium stibogluconate

Answer 48

Correct choice: E. Sodium stibogluconate
Explanation: The question stem describes a classic clinio-pathologic presentation of New World mucocutaneous leishmaniasis, which is most often due to L. braziliensis. First line treatment is with a pentavalent antimonial such as sodium stibogluconate or meglumine antimonite. Amphotericin B is the first line treatment for visceral leishmaniasis. The remaining answer choices are not useful in the treatment of New World mucocutaneous leishmaniasis.

Question 49

49- A female patient develops herpes simplex viral infections recurrently, at least 7 times per year. The infections are located on the lips. She has tried lysine daily as a treatment, what is the appropriate treatment for this patient without kidney disease?

A. Valacyclovir 2 g BID PO at first sign of outbreak then stop
B. Valacyclovir 1 g TID PO x 7 days at first sign of outbreak then stop
C. Valacyclovir 500 mg daily PO

D. Abreva topical BID at first sign of outbreak then stop
E. Lysine supplement TID x 7 days at first sign of outbreak then stop

Answer 49

Correct choice: C. Valacyclovir 500 mg daily PO
Explanation: The dose of valacyclovir for suppressive therapy for herpes simplex virus infections is 500 mg by mouth daily. Patients without significant renal impairment with 4-6 outbreaks of HSV per year (or more) are generally candidates. Valacyclovir 2 g by mouth and repeat dosage in 12 hours is the amount used for intermittent treatment of HSV. Valacyclovir 1 g by mouth TID x 7 days is the dosing schedule for herpes zoster. Abreva and lysine may possibly reduce the duration and severity of HSV outbreaks.

Question 50

50- A 3-year-old boy with a history of atopic dermatitis develops numerous monomorphic, punched-out erosions with hemorrhagic crusting and vesicles. It became widespread and affected the head, neck and trunk. Which of the following is not a complication that is commonly associated with this condition?

A. Superinfection with Staphylococcus aureus
B. Superinfection with Streptococcus pyogenes
C. Herpetic keratoconjunctivitis
D. Meningoencephalitis
E. Pneumonia due to Streptococcus pneumoniae

Answer 50

Correct choice: E. Pneumonia due to Streptococcus pneumoniae
Explanation: Eczema herpeticum represents rapid dissemination of a herpes simplex viral infection over the eczematous skin of AD patients. It initially develops as an eruption of vesicles, but affected individuals more often present with numerous monomorphic, punched-out erosions with hemorrhagic crusting. Eczema herpeticum is frequently widespread and may occur at any site, with a predilection for the head, neck, and trunk. It is often associated with fever, malaise, and lymphadenopathy, and complications may include superinfection with S. aureus or S. pyogenes as well as herpetic keratoconjunctivitis and meningoencephalitis. Patients with mutations in the filaggrin gene and those who have both severe AD and asthma have an increased risk for eczema herpeticum, and decreased production of antimicrobial peptides may have a pathogenic role. Patients with AD are also predisposed to the development of widespread molluscum contagiosum.

Superinfection with Staphylococcus aureus: Eczema herpeticum is often associated with fever, malaise, and lymphadenopathy, and complications may include superinfection with S. aureus or S. pyogenes as well as herpetic keratoconjunctivitis and meningoencephalitis.

Question 51

51- This condition is transmitted by what vector?

A. Black fly
B. Sandfly
C. Anopheles mosquito
D. Deer tick
E. Dog tick

Answer 51

Correct choice: B. Sandfly

Explanation: This is Leishmaniasis and is transmitted by the sandfly. The sandfly is the vector for Oroya fever/Carrion’s disease. Onchocerciasis is transmitted by the blackfly.

Question 52

52- In this patient, this test will be helpful in making the diagnosis:

A. Fluorescent antibody test for herpes
B. Patch test
C. Tissue culture
D. Indirect immunofluorescence
E. KOH exam

Answer 52

Correct choice: A. Fluorescent antibody test for herpes
Explanation: This patient has herpes zoster. A direct fluorescent antibody test for the varicella zoster virus can be performed to confirm the diagnosis

Question 53

53- What is the underlying infection in this neonate?

A. Syphilis
B. Leishmania
C. Chlamydia
D. Gonorrhea
E. Tuberculosis

Answer 53

Correct choice: A. Syphilis

Explanation: This is pemphigus syphiliticus, the only blistering manifestation of syphilis. It occurs in newborns. They have severe bullous lesions.

Question 54

54- Which of the following statements is false regarding this bacterial infection?

A. blister formation is mediated by epidermolytic toxin
B. the toxin binds to desmoglein 1
C. acantholysis occurs within the epidermal granular layer
D. the organism can be cultured from fluid wihtin the blisters
E. the organism cannot be cultured from fluid within the blisters

Answer 54

Correct choice: D. the organism can be cultured from fluid wihtin the blisters
Explanation: Most cases of staphylococcal scalded skin syndrome (SSSS) are caused by phage group II strains (e.g. types 55, 71) of S. aureus (which can be methicillin-sensitive or resistant) that produce exfoliative (also know as epidermolytic) toxins. ETA (chromosomally encoded) and ETB (plasmid encoded) are serine proteases that bind and cleave desmoglein 1. This causes splitting of the desmosomes, which leads to disruption of the epidermal granular layer and bulla formation. Desmoglein 1 is targeted by autoantibodies in pemphigus foliaceus, which has identical histological features to SSSS. In contrast to bullous impetigo, where the effects of the ETs are limited to the site(s) of infection, in SSSS the toxin diffuses from a focus of infection and (in the absence of specific antitoxin antibody) spreads hematogenously to produce widespread effects.

Question 55

55- The etiology of this infection falls into what category?

A. Amoeba
B. Protozoa
C. Bacteria
D. Fungus
E. Spirochete

Answer 55

correct choice: B. Protozoa

Explanation: This is granulomatous leishmania. Leishmania is a protozoa and is located within the macrophages. It is 2-3 microns in size and has a kinetoplast. It rims the macrophages.

Question 56

56- Which of the following is NOT associated with Pseudomonas aeruginosa?

A. Ecthyma gangrenosum
B. Rhinoscleroma
C. Green nail syndrome
D. Hot tub folliculitis
E. External otitis

Answer 56

Correct choice: B. Rhinoscleroma
Explanation: Rhinoscleroma is associated with Klebsiella pneumoniae, ssp. rhinoscleromatis.

Question 57

57- The visceral form of the infection depicted in this image is associated with which three major protozoan species:

A. L donovani, L infantum, L chagasi
B. L major, L donovani, L infantum
C. L aethiopica, L donovani, L major
D. L brazilensis, L major, L infantum
E. L Mexicana, L brazilensis, L infantum

Answer 57

Correct choice: A. L donovani, L infantum, L chagasi
Explanation: Infections with L. donovani (e.g. India, Bangladesh and the Sudan), L. infantum (e.g. Europe, especially in the setting of HIV infection) and L.chagasi (e.g. Central and South America) are the major causes of visceral leishmaniasis

Question 58

58- What is name of the possible reaction with treatment of this disease?

A. Tumor lysis syndrome
B. Jarisch-Herxheimer reaction
C. Asboe-Hansen
D. Rumple-Leede sign
E. Isomorphic phenomenon

Answer 58

Correct choice: B. Jarisch-Herxheimer reaction

Explanation: The Jarisch-Herxheimer reaction occurs with treatment of syphilis. It is due to TNF- alpha and other cytokines released when the spirochetes are phagocytosed. Tumor lysis syndrome occurs when chemotherapy is started in cancer patients. The isomorphic phenomenon is another name for the Koebner phenomenon. Rumple-Leede sign occurs after release of a tourniquet and there is a shower of petechiae. The Asboe-Hansen sign is when perpendicular pressure is applied to a blister and the blister enlarges. It is seen in pemphigus vulgaris and TEN.

Question 59

59- A teenage patient with several weeks of fatigue, fever, and pharyngitis develops a morbilliform eruption after receiving amoxicillin. The causative organism of his systemic symptoms may cause all of the following diseases EXCEPT:

A. Infectious mononucleosis
B. Extranodal NK/T-cell lymphoma (nasal type)
C. Oral hairy leukoplakia
D. Non-sexually related acute genital ulcers (Lipschutz ulcers)
E. Progressive multifocal leukoencephalopathy

Answer 59

Correct choice: E. Progressive multifocal leukoencephalopathy

Explanation: The correct answer is E. The question describes the ampicillin/amoxicillin rash associated with infectious mononucleosis and EBV infection. EBV causes all of the following except for E; JC virus causes PML.

Question 60

60- What is the vector for this disease?

A. Mosquito
B. Black fly
C. Tsetse fly
D. Sand fly
E. Mango fly

Answer 60

Correct choice: D. Sand fly

Explanation: The sand fly causes leishmania which is pictured here. The mango fly causes loa loa. The black fly causes onchocerciasis, the tsetse fly causes African trypanosomiasis.

Question 61

61- A 45 year old septic female develops symmetric, large ecchymotic areas with irregular borders on the extremities, ears, and nose. Laboratory testing reveals the patient has disseminated intravascular coagulation. Which of the following is the most common underlying infection associated with this condition?

A. Group A streptococcus
B. Meningococcus
C. Staphylococcus
D. Pseudomonas
E. Mycobacterium

Answer 61

Correct choice: B. Meningococcus
Explanation: Purpura fulminans is an oftentimes dramatic presentation of large ecchymotic areas of the skin, favoring acral sites including the extremities, ears, and nose. The underlying pathophysiology is hemorrhagic infarction of the skin due to disseminated intravascular coagulation. Meningococcal infection is the leading underlying infection associated with sepsis and purpura fulminans. When Kids develop purpura fulminans after an infection the most common cause is group A Strep.

Question 62

62- What is the causative organism?

A. Rubella
B. Parvovirus B19
C. Poxvirus
D. Paramyxovirus
E. Coxsackie

Answer 62

Correct choice: B. Parvovirus B19
Explanation: This is erythema infectiosum, with the slapped cheek appearance. It is due to parvovirus B19. Paramyxovrus causes the measles, molluscum is due to a poxvirus, orf is due to a parapoxvirus. Rubella is due to a togavirus. Coxsackie causes hand-foot-mouth disease and herpangina.

Question 63

63- An infant presents to your pediatric dermatology clinic with acral vesiculopustules and intense itching. Confirmation of the diagnosis is achieved by light microscopic examination of a mineral oil preparation from a skin scraping (shown in photo). Which of the following statements is FALSE?

A. The mites that cause infestations in animals are not a source of human infestation

B. The incubation period before symptoms develop can range from days to months
C. Each day a female mite lays 3 eggs, which require approximately 10 days to mature
D. The mite is too small to be seen by the naked eye
E. The 30-day life cycle is completed within the dermis

Answer 63

Correct choice: E. The 30-day life cycle is completed within the dermis
Explanation: Human scabies is caused by the species-specific, eight-legged mite Sarcoptes scabiei var. hominis shown in the mineral oil prep in the above image. The 30-day life cycle is completed within the epidermis. Acral vesiculopustules can represent a clue to the diagnosis of scabies in infants. Confirmation of diagnosis can be achieved by light microscopic examination of mineral oil preparations of skin scrapings from infested areas for adult mite, eggs or fecal pellets. A scalpel or curette may be used to obtain the skin sample. Microscopic examination of transparent adhesive tape following its application to infested areas of skin represents another diagnostic technique. This image shows an adult female mite and is a light microscopic examination of a mineral oil preparation of a skin scraping in a patient with scabies.

1 – The specific Sarcoptes mite that causes infestation in animals is not a source of human infestation, but can produce bite reactions. 2 – The incubation period before symptoms of scabies develop can range from days to months. In first-time infestations it takes 2-6 weeks before the host’s immune system becomes sensitized to the mite or its by-products, resulting in pruritus and cutaneous lesions. 3 – Each day a female lays 3 eggs which require approximately 10 days to mature. Scabies mites usually live 3 days or fewer off a human host, but may live up to 7 days in patients with crusted scabies. 4 – The scabies mite is 0.35 x 0.3 mm in size and thus is too small to be seen by the naked eye.

Question 64

64- If this patient were pregnant and allergic to penicillin what would be the appropriate treatment?

A. Treatment with penicillin and treatment of the allergic reaction
B. Desensitization to penicillin
C. Azithromycin
D. Ciprofloxacin
E. Gentamicin

Answer 64

Correct choice: B. Desensitization to penicillin
Explanation: This is a cutaneous gumma in late syphilis. The treatment for late syphilis is penicillin. If this patient was pregnant and allergic to penicillin the patient would need to undergo desensitization to penicillin and then be treated with penicillin

Question 65

65- Which of the following is the best test to diagnose cutaneous herpes simplex virus infection?

A. Lesional viral culture
B. Lesional direct fluorescence antibody testing
C. Lesional polymerase chain reaction assay
D. Blood viral culture
E. Urine nucleic acid amplification test

Answer 65

Correct choice: C. Lesional polymerase chain reaction assay
Explanation: Recent recommendations from both the Infectious Diseases Society of America and the American Society for Microbiology characterize lesional nucleic acid amplification testing, such as PCR, as the “most sensitive, specific, and rapid test for diagnosis of HSV-associated skin or mucosal lesions.” Lesional DFA testing or lesional viral cultures may be used to diagnose cutaneous HSV infection, although these tests have lower sensitivity and/or specificity compared to PCR. Blood viral cultures are typically not helpful when trying to diagnose cutaneous HSV infection. Lastly, urine nucleic acid amplification tests can be used to diagnose certain sexually-trasmitted infections (e.g. Chlamydia, Gonorrhea), however they are not helpful for HSV.

Question 66

66- This lesion develops how long after the infectious exposure?

A. 20 years
B. 10 days to 3 months
C. 10 years
D. 1-9 days
E. 4 to 6 months

Answer 66

Correct choice: B. 10 days to 3 months
Explanation: This is a perianal chancre of primary syphilis following anal intercourse. The chancre is non-tender and presents 10 days to 3 months after syphilis exposure.

Question 67

67- This infectious lesion appeared very rapidly after surgery and started as a nodule that now looks like the photograph, what is the treatment of choice after drainage?

A. Clindamycin
B. Minocycline
C. Doxycycline
D. Clarithromycin
E. No treatment after drainage

Answer 67

Correct choice: D. Clarithromycin
Explanation: This is a mycobacterial infection after surgery which is usually due to M. Chelonei. It presents with SQ nodules that ulcerate and drain. The treatment is to drain and treat with clarithromycin as first-line antibiotic therapy.

Question 68

68- A patient with any stage of this infection should always be tested for:

A. herpesvirus
B. hepatitis
C. Chlamydia trachomatis
D. Neisseria gonorrhea
E. HIV infection

Answer 68

Correct choice: E. HIV infection
Explanation: All patients who have syphilis should also be tested for HIV infection

Question 69

This patient has less than three lesions which are
anesthetic and anhidrotic. What cytokine profile does this condition have?
A. Th2
B. IL-23
C. Th1

D. Th1 and Th2
E. Th17

Answer 69

Correct choice: C. Th1
Explanation: This is tuberculoid leprosy which classically has a low concentration of organisms because the body is reacting to the M. leprae. Thus the patients get anesthesia and anhidrosis. There are typically less than three hypopigmented patches. Tuberculoid leprosy is associated with a Th1 cytokine profile including IFN-gamma, IL-2 and IL-12. Lepromatous leprosy is Th2.

Tuberculoid leprosy can be either one large red patch with well-defined raised borders or a large hypopigmented asymmetrical spot. Lesions become dry and hairless. Loss of sensation may occur at the site of some lesions. Tender, thickened nerves with subsequent loss of function are common. Spontaneous resolution may occur in a few years or it may progress to borderline or rarely lepromatous types. Leprosy has very characteristic clinical features but the diagnosis must be confirmed because of the need for prolonged treatment with antibiotics. A skin biopsy may show characteristic histopathology with granulomas (mixed inflammatory cell infiltrate in the deeper layers of the skin, the dermis) and involvement of the nerves. Special staining of the tissue may show acid-fast bacilli, the number visible depending on the type of leprosy. Immunohistochemistry stains can be helpful when the bacilli are few in number.The bacteria may also be found in lepromatous leprosy on smears taken from skin slits made in the ear lobes, but the smears will be negative in the tuberculoid or borderline forms of the disease.
Lepromatous leprosy. Lepromatous leprosy is a form of leprosy characterized by pale macules in the skin. In lepromatous leprosy, TH2 response is turned on, and because of reciprocal inhibition (IL-4; IL-10), the cell-mediated response (TH1) is depressed.

Question 70

70- Which of the following is true regarding sporotrichosis?

A. The disseminated form is common
B. Transmission usually occurs via direct inoculation
C. Sclerotic bodies are seen histologically
D. Supersaturated potassium iodide (SSKI) is the most common treatment
E. It is found in pigeon droppings

Answer 70

Correct choice: B. Transmission usually occurs via direct inoculation

Explanation: Sporotrichosis is caused by Sporothrix schenckii, a dimorphic fungus found in soil, thorns, moss, and bark. Transmission may occur via direct inoculation or inhalation, though it usually occurs when the fungus enters the skin through a small cut or scrape, usually after someone touches contaminated plant matter. Sporotrichosis has three different forms: lymphocutaneous, fixed cutaneous, and disseminated. The disseminated form is rare. While SSKI may be used to treat lymphocutaneous sporotrichosis, itraconazole is the most common treatment. Cryptococcus neoformans is found in pigeon droppings. Sclerotic bodies (aka Medlar bodies or copper pennies) are seen histologically in chromomycosis (aka chromoblastomycosis), whereas asteroid bodies are typically seen histologically in sporotrichosis.

Question 71

71- What is the most likely organism?

A. Leishmania
B. Corynebacterium minutissimum
C. Trichophyton Rubrum
D. Hortaea werneckii
E. There is no organism, this is normal skin

Answer 71

Correct choice: C. Trichophyton Rubrum
Explanation: This is a dermatophyte infection located in the stratum corneum. Trichophyton Rubrum is a common cause of dermatophyte infection. Hortaea werneckii causes tinea nigra, which would show pigmented hyphae on histology. Leishmania presents with amastigotes (tiny dots) within macrophages (Leishman-Donovan bodies); the dermis contains an infiltrate of histiocytes, lymphocytes, and plasma cells. The organisms are best seen with the Giemsa stain.

Question 72

72- What is the most likely cause of this eruption (buttocks tinea)?

A. Trichophyton tonsurans
B. Trichophyton mentagrophytes
C. Trichophyton rubrum
D. Microsporum canis
E. Microsporum gypseum

Answer 72

Correct choice: C. Trichophyton rubrum
Explanation: This is tinea corporis, which is most often due to T. rubrum. The remaining answer choices may also produce tinea corporis, but less commonly than T. rubrum.

Question 73

73- Transmission of this eruption is primarily via which route?
A. Contact
B. Respiratory
C. Food borne
D. Bloodborne
E. Insect borne

Answer 73

Correct choice: B. Respiratory
Explanation: Varicella is primarily spread via respiratory droplets, and less frequently, direct contact. Varicella is not spread by bloodborne, insect borne, or food borne mechanisms.

Question 74

74- A 28-year-old HIV-infected male presened with superficial angiomatous papules and nodules, violaceous lichenoid plaques, and deep subcutaneous nodules. The skin lesions resembles pyogenic granulomas and were smooth and pedunculated. In addition, the patient presented with nausea, vomiting, diarrhea, abdominal pain, hepatosplenomegaly, and elevated liver enzymes. Which of the following immunohistochemical stains would be useful in identifying this lesion?

A. Verfoeff-van Gieson
B. Alizarin red
C. Trichrome blue

D. Warthin-Starry
E. Sudan black

Answer 74

Correct choice: D. Warthin-Starry

Explanation: Biopsy specimens of bacillary angiomatosis reveal lobular proliferations of capillaries and venules, plump and protuberant endothelial cells, and a marked neutrophilic infiltrate with evidence of leukocytoclasis throughout the interstitium. In H&E-stained sections, interstitial clumps of bacilli appear as purplish granular material. Bacteria can be readily identified with a Warthin– Starry stain.
2- Trichrome stains collagen blue.
3- Verhoeff–Van Gieson stain is used to demonstrate normal or pathologic elastic fibers.
4- Sudan black stains lipids
5- Alzarin redis commonly used in histology to highlight calcium deposits by binding to it by a chelation process. The reaction enable the formation of alizarin red S-calcium, a birefringent compound which deposits appears optically in red.

Question 75

75 -This HPV strain is responsible for Bushke-Lowenstein tumor and also for anogenital warts:

A. HPV 6, 11
B. HPV 1
C. HPV 2, 4
D. HPV 3, 10
E. HPV 7

Answer 75

►A

Anogenital and Buschke-Lowentein tumor is caused by HPV 6 and 11. HPV 1 is from palmoplantar warts. HPV 2, 4 causes common warts HPV 7 causes Butcher’s warts.

Question 76

76 -The causative organism that is responsible for pitted keratolysis is:

A. Micrococcus sedentarius
B. Streptobacillus moniliformis
C. Klebsiella pneumonia
D. Neisseria meningitides
E. Burkholderia mallei

Answer 76

►A

Pitted keratolysis is caused by Micrococcus sedentarius. The clinical features are shallow 1 -3mm pits on plantar surface of feet. The treatment is topical erythromycin, clindamycin, or benzoyl peroxide.

Question 77

77 -Most common causative agent for the lesion shown in this 5-year old child is

A. Staphylococcus aureus
B. group A β-hemolytic streptococci
C. Pseuomonas
D. kleibsiella
E. H.influenza

Answer 77

►A

The picture shown is Impetigo, which is a common, contagious superficial skin infection caused most commonly by staphylococci. Although seen in all age groups, the disease is most common in infants and children. Lesions may involve any body surface but occur most frequently on the
7 exposed parts of the body, especially the face, hands, neck, and extremities. There are two classic forms of impetigo, bullous and nonbullous. Nonbullous impetigo accounts for more than 70% of cases. Historically was caused primarily by group A β-hemolytic streptococci (GABHS), but now appears to be most commonly caused by S. aureus. Anaerobic organisms may also be recovered from lesions of nonbullous impetigo. (Reference: Brook I, Frazier EH, Yeager JK. Microbiology of nonbullous impetigo. Pediatr Dermatol 1997;14(3):192-195.)

Question 78

78- A 4 year-old boy is diagnosed with Staphylococcal Scalded-Skin Syndrome. Vesiculation in this disease is secondary to exfoliative toxins binding what target protein?

A. Plectin
B. Bullous pemphigoid antigen 2
C. Bullous Pemphigoid antigen 1
D. Desmoglein 3
E. Desmoglein 1

Answer 78

►E

Staphylococcus Scalded-Skin Syndrome (SSSS) is caused by Staphylococcus exfoliative toxins A and B binding desmoglein 1. This results in the intraepidermal split at the granular layer seen in this illness. Targeting of desmoglein 3 would result in a suprabasilar split. Targeting of plectin, BPAG1, or BPAG2 would result in a subepidermal split. This is not seen in SSSS.

Question 79

79- Tick-borne Relapsing Fever is caused by:

A. B. burgdorferi
B. B. recurrentis
C. B. duttonii
D. B. henselae
E. B. bacilliformis

Answer 79

►C

Relapsing Fever can be either Louse-borne or Tick-borne. Tick-borne Relapsing Fever is caused by
B. duttonii or B. hermsi, while Louse-borne Relapsing Fever is caused by B. recurrentis.

Question 80

80- Staphylococcal scalded skin syndrome is caused by exfoliative toxins binding to:

A. Desmoglein-1
B. Desmokolin-1
C. TSST-1
D. Laminin-5
E. Desmoglein-3

Answer 80

►A

Staph scaled skin syndrome is caused by Et-A and ET-B that bind to desmoglein-1. Children under 5 years of age, adults with renal failure or immunodeficiency. Also a Nikolsky’s sign is seen in lesional and non-lesional skin with a subgranular blister.

Question 81

81- Which human papillo virus (HPV) type is implicated in papillomatosis cutis carcinoides di Gottron?

A. 7
B. 11
C. 18
D. 57
E. 60

Answer 81

►B

Papillomatosis cutis carcinoides di Gottron, also known as Gottron’s tumor, is a verrucous carcinoma of the skin. In 1948, Ackerman first described verrucous carcinoma (VC), a low-grade tumor that generally is considered a clinicopathologic variant of squamous cell carcinoma. Verrucous carcinomas are caused by HPV types 6 and 11. When they occur on the feet they are called epithelioma caniculatum. When they occur on the genitals they are refered to as BuschkeLowenstein tumors. When they occur in the mouth they are called Ackerman’s tumors or oral florid papillomatosis.

Question 82

82- Which of the following is a characteristic of papilloma viruses?

A. enveloped viruses
B. single stranded RNA viruses
C. replicate independent of the host cell
D. controlled by host antibody regulated response
E. can cause a condition that manifests with stridor and hoarseness in children

Answer 82

►E

Papilloma viruses are non-enveloped,double stranded DNA viruses. Cell mediated responses are primarily responsible for controlling papillomavirus infections. Unlike viruses such as HSV, HPV does not have enzymes required for replication of viral DNA, and is entirely dependent on the host cellular machinery. Recurrent respiratory papillomatosis can be caused by HPV -6 and 11, with verrucous lesions of the airways. It can occur as a juvenile or adult -onset form and present with hoarseness in children. Unlike viruses such as HSV, HPV does not enzymes 9 required for replication of viral DNA, and is entirely dependent on the host cellular machinery for these functions.

Question 83

83- The dominant organism present on oily regions of the skin is:

A. Gram positive coagulase negative staphylococcus
B. Staphylococcus aureus
C. Propionibacterium acnes
D. Corynebacterium spp.
E. Propionibacterium avidum

Answer 83

►C

The most common organism on sebaceous regions of human skin is Propionibacterium acnes. This is an aerotolerant, anaerobic gram positive club-shaped diptheroid that lives in the depths of the sebaceous follicle. It has a potent lipase which cleaves sebaceous triglycerides into glycerol and free fatty acids. The free fatty acids lower the pH and are thought to retard the growth of pathogens such as S. aureus. Other residents of oily regions are: Malassezia furfur, S. epidermidis, Micrococcus luteus and other catalase positive aerobic cocci. S. aureus is a pathogen, and is not considered normal flora of any region of the skin. The other options are found on dry or moist regions of the skin.

Question 84

84- Measles is caused by which type of virus?

A. Paramyxovirus
B. Togavirus
C. Picornavirus
D. Rhabdovirus
E. Parvovirus

Answer 84

►A

Measles is caused by an RNA virus known as paramyxovirus. The illness is characterized by high fever, cough, coryza, conjunctivitis, and Koplik’s spots. Viral exanthem characterized by erythematous macules and papules beginning on the face and spreading caudally 3-4 days after prodromal symptoms.

Question 85

85- A 12 year old girl presents complaining of multiple warts on the fingers that have been recalcitrant to common over-the-counter treatments. What is the clearance rate of untreated common warts in children at 2 years after diagnosis?

A. 25-30%
B. 50-55%
C. 70-75%
D. 1%

E. 5-10%

Answer 85

►C

While warts can be very difficult and frustrating to treat, the spontaneous clearance rate at two years is actually quite high (70-75%).

Question 86

86- A 28 year old sexually active female presents to clinic complaining of new growths of her labia majora. Examination reveals condyloma acuminatum, and biopsy with immunohistochemistry confirms the diagnosis of human papilloma virus infection. Condyloma accuminatum is most commonly caused by what HPV type?

A. 6 and 11
B. 16 and 18
C. 1 and 3
D. 31 and 33
E. 48 and 60

Answer 86

►A

While many subtypes of HPV are associated with genital warts, 6 and 11 are the most common. In general, potentially oncogenic HPV subtypes such as 16 and 18 cause sessile genital warts.

Question 87

87- What is the most common subtype of molluscum contagiosum virus infection seen in HIV patients?
A. MCV-1
B. MCV-2
C. MCV-3
D. MCV-4
E. MCV-5

Answer 87

►B

The most common subtype of molluscum contagiosum virus is MCV-1. In HIV patients, however, MCV-2 is more common.

Question 88

88- The treatment of choice for Loiasis is:

A. Ivermectin
B. Diethylcarbamazine (DEC)
C. Permethrin
D. Malathion
E. Chloramphenicol

Answer 88

►B
The recommended treatment for loiasis is Diethylcarbamazine (DEC).

Question 89

89 -Congenital Varicella Syndrome occurs after maternal varicella infection during which stage of pregnancy?

A. First 20 weeks
B. Third trimester
C. 5 days before and 2 days after delivery
D. 20-24 weeks
E. None of these answers are correct

Answer 89

►A

Congenital Varicella Syndrome occurs after maternal varicella-zoster virus infection early in pregnancy (up to 20 weeks gestation).

Question 90

90- The most common agent of cutaneous and furuncular myiasis in North America is:

A. Dermatobia hominis

B. Gasterophilus intestinalis
C. Wohlfahrtia magnifica
D. Hypoderma hominis
E. Cuterebra intestinalis

Answer 90

►A

Dermatobia hominis is most common agent of cutaneous and furuncular myiasis in North America, but Cuterebra spp. are also a frequent cause of furuncular myiasis in the US. Complications of myiasis are tetanus and secondary bacterial infection.

Question 91

91- A 28 year-old man presents with fever, chills, arthralgias and the cutaneous lesions shown. The most likely diagnosis is:

A. Purpura fulminans
B. Rickettsialpox
C. Anthrax
D. Gonoccemia
E. Primary herpes simplex infection

Answer 91

►D

The image shows sparsely distributed hemorrhagic vesiculopustules with erythematous bases on an acral surface. These features are characteristic of gonococcemia.

Question 92

92- A 48 year-old woman presents to the Emergency Room with a 2 day history of fever and a well demarcated erythematous plaque on her right cheek. What is the treatment of choice?

A. Prednisone
B. Intravenous penicillin
C. Cephalexin
D. Fluconazole
E. Potent topical corticosteroid

Answer 92

►B

The most likely diagnosis is Erysipelas which is caused by beta -hemolytic group A streptococcus. The treatment of choice is intravenous penicillin.

Question 93

93- Orf virus infection is also known as:

A. Ecthyma
B. Ecthyma contagiosum
C. Echtyma gangrenosum
D. Pseudocowpox
E. Milker’s nodule

Answer 93

►B

Orf virus infection is also known as Ecthyma contagiosum. Ecthyma Gangrenosum is caused by Pseudomonas aeruginosa. Ecthyma is caused by Staphylococcal or streptococcal pyoderma. Pseudocowpox and Milker’s nodule are also known as paravaccinia and caused by udders of infected cows.

Question 94

94- A patient develops herpes zoster in the V1 distribution. A few days after development of the classic vesicular rash, her family brings her to the emergency room because of new onset seizures. She had been complaining of confusion, headache, fatigue, and loss of appetite prior to the convulsions. What is the diagnosis?

A. Syndrome of inappropriate anti-diuretic hormone
B. Ramsay-Hunt syndrome
C. Delayed contralateral hemiparesis
D. Post-zoster neuropathy
E. Intracerebral vasculitis

Answer 94

►A

The question stem describes signs and symptoms of hyponatremia. The syndrome of inappropriate antidiuretic hormone secretion is a known, albeit rare, complication of varicella zoster virus infection. The other four answer choices are also known complications of varicellazoster virus infection, but do not cause the disease presentation as described.

Question 95

95- What laboratory finding is commonly seen in children with measles virus infection?

A. Lymphopenia
B. Thrombocytosis
C. Polycythemia
D. Anemia
E. Lymphocytosis

Answer 95

►A

Children who are actively infected with the measles virus are commonly found to have lymphopenia. While an abnormality of any of the blood cell lines is possible during viral infections, in the case of measles infections, lymphopenia is most common. However, cbc may reveal a relative lymphocytosis and thrombocytopenia.

Question 96

96- The vector for relapsing fever that causes paroxysmal fevers, headaches, mylagias and erythematous or petechia macules in refugees is:

A. Pediculus humanus
B. Ornithodoros
C. Ixodes dammini
D. Ixodes pacificus
E. Ixodes ricinus

Answer 96

►A

Relapsing fever is caused by the human body louse Pediculus humanus and the borrelia species is
B. recurrentis. The clinical features are paroxysmal fevers, headache, lymphocytoma, mylagias,

erythematous or petechial macules on trunk and extremities.Louse-borne relapsing fever is transmitted by the human body louse and is generally restricted to refugee settings in developing regions of the world.Tick-borne relapsing fever has the same symptoms occurs in the
western United States and is usually linked to sleeping in rustic, rodent-infested cabins in mountainous areas. The vector for tick borne is ornithodoros and it is due to Borrellia duttonii.

Question 97

97- A 19 year old sexually active male presents with a painful ulcer on the shaft of his penis. A biopsy specimen stained with Giemsa reveals a “school of fish.” Which of the following is the causative organism?

A. Hemophilus ducreyi
B. Treponema pallidum
C. Calymmatobacterium granulomatis
D. Chlamydia trachomatis L1
E. Herpes simplex virus

Answer 97

►A

Chancroid is a sexually transmitted disease caused by the bacteria Hemophilus ducreyi. It is one of many organisms that can cause a genital ulcer. Chancroid is characterized by a soft, painful chancre with ragged edges. Giemsa stained sections reveal a “school of fish” configuration which is typical. Treatment is with azithromycin, ceftriaxone, ciprofloxacin, or erythromycin.

Question 98

98- Epithelioma cuniculatum is an HPV-associated verrucous carcinoma involving the:

A. Oral mucosa
B. Scalp
C. Sole
D. Penis
E. Trunk

Answer 98

►C

Epithelioma cuniculatum is a form of verrucous carcinoma involving the sole.

Question 99

A patient had a severe febrile illness with hemolytic anemia and now has exophytic nodules on the trunk, extremities and face. Which of the following organisms is the cause?

A. Bartonella henselae
B. Bartonella quintana
C. Bartonella bacilliformis
D. Rickettsia rickettsii
E. Rickettsia akari

Answer 99

►C

The first stage of this condition is known as Carrion‟s disease, which can be fatal. It was in Dr. Carrion (as a medical student), who self inoculated himself to prove that the cause of verruga peruana (the second stage described above) was the same as that of the first stage. The cause of both Carrion‟s disease and verruga peruana is Bartonella bacilliformis. B. henselae is the cause of Cat Scratch disease while B. quintana causes Trench Fever. Rickettsia rickettsii is the cause of Rocky Mountain Spotted Fever and Rickettsia akari causes Rickettsial pox.

Question 100

The diagnosis of leishmaniasis can be confirmed by which of the following techniques?

A. Weil-Felix test
B. Warthin-Starry stain
C. Culture in Sabourad’s agar
D. Culture in Novy-MacNeal-Nicolle (NNN) medium
E. Culture in Michel’s medium

Answer 100

►D

Confirmation of infection with Leishmaniasis is performed by culture in Novy-MacNeal-Nicolle (NNN) medium.

Question 101

101- What is the most common presentation of mucous membrane involvement of EBV infection?

A. Buccal ulcers with superficial slough
B. Erosions of the gingivae
C. Plication of the tongue
D. Palatal petechiae
E. Oral hairy leukoplakia

Answer 101

►D

The most common presentation of intra-oral involvement of EBV infection is pinpoint petechiae of the junction of the hard and soft palate. The associated eponym is Forchheimer spots. Forchheimer spots are not pathognomonic for EBV infection, as they can be seen in measles, rubella, and scarlet fever. While oral hairy leukoplakia is associated with EBV infection, it is not the most common mucous membrane sign.

Question 102

102- A 4 year old girl experiences systemic symptoms including fever, fatigue, headache, and vomiting. An associated exanthem consists of a non-pruritic eruption including the formation of blisters on the palms and soles and an intra-oral ulcer. Hand-foot-mouth syndrome is diagnosed. What nail finding can be seen approximately 1 month after infection with Coxsackie virus and other Enteroviruses?

A. Onychomadesis
B. Onycholysis
C. Trachyonychia
D. Terry’s nails
E. Paronychia

Answer 102

►A

Although rare, onychomadesis has been associated with enteroviral infections, including handfoot- mouth syndrome due to Coxsackie virus. Onychomadesis is an idiopathic shedding of the nails beginning at the proximal end. It may be due to temporary arrest of the matrix during the infection. In most cases, the nails return normally.

Question 103

103 -A 1 year old female patient is brought in by her mother because of the development of warty growths peri-anally. A clinical examination and biopsy confirms the diagnosis of peri-anal warts. In 11 month old patients, what is the most common cause of acquisition of human papilloma virus.

A. Vertical transmission peri-natally
B. Sexual abuse
C. Contact with a wart-containing finger
D. Contact with a fomite
E. Aerosol transmission

Answer 103

►A

In any child with peri-anal warts, the possibility of sexual contact must be excluded. Fortunately, in infants up to 12 months of age, the most common route of acquisition of the human papilloma virus is vertical transmission at the time of delivery.

Question 104

• Epidermodysplasia verruciformis is caused by which human papilloma virus (HPV) types?

A. 6 and 11
B. 16 and 18
C. 5, 8, and 9
D. 3 and 10
E. 13 and 32

Answer 104

►C

Epidermodysplasia verruciformis is caused by HPV types 5, 8, 9, 12, 14, 15, 17, 19-26.

Question 105

105 -A child presents with fever, cutaneous tenderness and erythema of flexural and periorifacial areas. Within 24 hours the erythema progresses to flaccid blisters and erosions. No organisms are cultured and Nikolsky’s sign is positive. First line therapy includes:

A. IV penicillinase resistant penicillin with clindamycin

B. Aspirin
C. IV IgG
D. PO tetracylcine
E. PO cephalexin

Answer 105

►A

First line therapy for SSSS includes IV penicillinase resistant penicillin. Second line therapy is IV macrolide treatment. Third line therapies are cephalosporin and vancomycin. Clindamycin is added to curtail toxin production.

Question 106

106- Name the syndrome defined by gonorrhea with perihepatitis and liver adhesions.

A. Lhermitte-Duclos Syndrome
B. Turcot Syndrome
C. Fitz-Hugh-Curtis Syndrome
D. Leser-Trelat Syndrome
E. Clutton’s Syndrome

Answer 106

►C

Gonorrhea, caused by a gram negative intracellular diplococcus, often presents cu taneously with hemorrhagic vesiculopustules of the distal extremities. Septic arthritis is also an important presentation of gonococcemia, most commonly involving the knee.

Question 107

107- A 48-year-old Latin American female with a diagnosis of leprosy develops bullous lesions that appear rapidly and ulcerate, especially below the knee. This most likely represents:
A. Reversal reaction
B. Upgrading reaction
C. Erythema nodosum leprosum
D. Lucio’s phenomenon
E. Lofgren’s syndrome

Answer 107

►D

This patient has a type III reactional state to leprosy called Lucio’s phenomenon. It mostly occurs in people of Latin American descent and is characterized by rapidly ulcerating and bullous lesions usually on the legs. It has a high mortality rate. A type I reaction, or a reversal/upgrading reaction, can occur after treatment and are associated with a change in cell-mediated immunity and result in accelerated destruction of bacilli. This is manifested as inflammation of existing lesions with no systemic symptoms. A type II reaction, or erythema nodosum leprosum, represents an immune complex deposition and features widespread erythematous nodules with systemic features. Lofgren’s is associated with sarcoidosis.

Question 108

108- An AIDS patient develops a smooth papule with a collarette of scale with vascular proliferation seen on biopsy and is seen with those in contract with cats. The most likely cause of this is:

A. Bartonella hensalae
B. Brucellosis hensale
C. Pseudomonas mallei
D. Bacillus anthracis
E. Pasteurella

Answer 108

►A

This is bacillary angiomatosis and is caused by Bartonella hensalae and can be associated with contact with cats in 20% of cases and occurs in patients with AIDS. The disease is treated with a macrolide antibiotic or doxycycline.

Question 109

109- A 27 year-old HIV positive presents with this pruritic eruption? What is the characteristic cell type found on histopathology?

A. Neutrophil
B. Plasma Cell
C. Basophils
D. Eosinophil

E. Lymphocyte

Answer 109

►D

Eosinophilic pustular folliculitis is a pruritic disorder that may be seen in HIV positive patients. Typically, the CD4 count is < 300. In patients with HIV, pruritus tends to improve after institution of anti-retroviral therapy.

Question 110

110- A 43 year-old man with uncontrolled HIV disease presents with yellowish, red papules, draining sinuses and ulcers perianally and periurethrally. Which histopathological or immunohistochemical stain may aid in diagnosis?

A. CD3
B. CD20
C. Von Gieson (EVG)
D. Von Kossa
E. Steiner

Answer 110

►D

The most likely diagnosis is malacoplakia. Malacoplakia, an infection usually attributed to S. aureus, P. aeruginosa, or E. coli is characterized histopathologically by Michelis -Gutmann bodies. These are foamy eosinophilic macrophages containing calcified, laminated, intracytoplasmic bodies. They can be highlighted by a calcium stain such as von Kossa. CD3 and CD20 are lymphocyte markers, von Gieson is an elastic tissue stain, and Steiner stain is used to highlight spirochetes. These would not aid in the diagnosis of malacoplakia.

Question 111

11. -The main deterrent to staphylococcal infection of the skin is:

A. Complement
B. Neutrophils
C. Macrophages
D. Immunoglobulin
E. CD8+ T-cell mediated immunity

Answer 111

►B

The main deterrent to staphylococcal infection is the neutrophils. These contain bactericidal chemicals and proteins such as myeloperoxidase-H202-halide, lysozyem, serine proteases, defensins and bacterial permeability increasing peptide. Complement serves as an effective opsonin for phagocytosis by circulating neutrophils and macrophages. Immunoglobulin response hastens phagocytosis but is not absolutely required. Cytotoxic T-cells do not play a major role in controlling
S. aureus infections.

Question 112

112- What named nerve is involved in the formation of Hutchinson’s sign (vesicles at the nasal tip) in herpes zoster?

A. Ophthalmic nerve
B. V2 (maxillary)
C. Nasociliary
D. Infratrochlear nerve
E. Labial nerve

Answer 112

►C

Hutchinson’s sign is defined by vesicles at the nasal tip in a patient with facial herpes zoster. It is caused by VZV invovlement of the nasociliary nerve. Patients suffering with this sign should be screened for ophthalmologic herpes zoster invovlement.

Question 113

113- Cat scratch disease is from transmission from infected cats to humans and the treatment for the disease is:

A. Spontaneous resolution in the majority of cases
B. Erythromycin
C. Doxycycline
D. Cloramphenicol
E. Minocycline

Answer 113

►A

Cat scratch disease is caused by B. henselae. It is from the flea-Ctenocephalides felis. It spontaneous resolution in most of cases.

Question 114

114. A- goatherder develops this painless pustule that subsequently forms a black eschar. What causes the edema to form in this lesion?

A. Increased levels of cAMP
B. Release of TNF-alpha
C. Release of IL-1beta
D. Inhibition of phagocytosis
E. C1 esterase inhibitor

Answer 114

►A

Anthrax is caused by Bacillus anthracis, a gram positive spore-forming rod. Anthrax is primarily seen in individuals who are in contact with wild or domestic animals. Recent cases have been linked with bioterrorism. B. anthracis produces edema toxin and lethal toxin. Edema toxin is comprised of edema factor and protective antigen. Edema factor is a calmodulin dependent adenyl cyclase. The increased cAMP induces the gelatinous edema of anthrax skin lesions.

Question 115

115- Which of the following vectors is responsible for transmitting Chagas‟ disease?

A. Tstse fly
B. Reduviid bug
C. Black fly
D. Mosquito
E. Sandfly

Answer 115

►B

The reduviid big is the vector of American trypanosomiasis (Chagas disease). The vector of African trypanosomiasis is the tstse fly.

Question 116

116- What is the causative agent of this parasitic eruption which also causes patchy pulmonary infiltrate and eosinophilia?

A. Dracunculiasis
B. Gnathostomiasis
C. Ground itch
D. Larva migrans
E. Larva currens

Answer 116

►C

Larva migrans is caused by Ancylostoma braziliense, a hookworm of cats and dogs. It does not leave the epidermis because it lacks collagenase. Larva currens is due to strongyloides and presents with serpiginous lesions on the buttock, thighs or perianally. Ground itch is due to ancylostoma duodenale and necator americanus which clinically present like cutaneous larva migrans but are able to leave the epidermis, therefore causing fuplomany infiltrates and eosiniophilia. Loeffler’s syndrome, is the name for the patchy infiltrate of the lungs with eosinophilia. Treatment for this parasitic infection is ivermectin or albendazole or thiabendazole.

Question 117

117- Treatment of severe nodulocystic acne with which of the following vitamin derivatives may completely arrest the disease process through decreasing P. acnes?

A. Vitamin D
B. Vitamin A
C. Vitamin K
D. Vitamin E
E. Vitamin B3

Answer 117

►B

13-cis-retinoic acid (isotretinoin/Accutane) is a derivative of vitamin A. It has several mechanisms of action in acne. It rapidly suppresses sebum production, causing a decrease in P. acnes populations. It also decreases follicular plugging by an uncertain mechanism. Vitamins D, K and E are fat soluble vitamins, but are not able to completely arrest the disease process in acne. Vitamin B3 is niacin and is associated with a diet of exclusively of corn, millet or sorghum. Other sources: carcinoid, Hartnup disease, parasites, GI disorders, IV nutrition, and psychiatric disease. Findings include the 3 D‟s: Diarrhea, Dementia, Dermatitis.

Question 118

118- The Jarisch-Herxeimer reaction is most closely associated with the release of which of the following cytokines?

A. IFN-alpha
B. IL-12
C. TNF-alpha
D. IL-4
E. IL-10

Answer 118

►C

TNF-alpha. The Jarisch-Herxheimer reaction is associated with increased plasma concentrations of TNF-alpha after antibiotic treatment of syphilis. The Jarisch-Herxheimer reaction has also been described following treatment of louse-borne relapsing fever, lyme disease and leptospirosis.

Question 119

119- A patient with HIV/AIDS presents with vesicles in a disseminated distribution. A biopsy is performed. Which histologic finding favors infection with varicella-zoster virus over herpes simplex virus?

A. Pseudoepitheliomatous hyperplasia
B. Margination of keratinocyte nuclei
C. Multinucleated cells
D. Superficial dermal leukocytoclastic vasculitis
E. Molding of nuclei

Answer 119

►D

Herpes simplex virus and disseminated varicella-zoster virus infection can be difficult to distinguish clinically and histologically. These viruses share the histologic findings of margination of nuclei, multinucleated cells, and nuclear molding. The presence of leukocytoclastic vasculitis favors a diagnosis of disseminated varicella-zoster virus.

Question 120

120- Woolsorter‟s disease is caused by:
A. Erysipelothrix rhusiopathiae
B. Listeria monocytogenes
C. Corynebacterium minutissimum
D. Corynebacterium tenius
E. Bacillus anthracis

Answer 120

►E

Anthrax, also known as woolsorter‟s disease or malignant pustule is caused by Bacillus anthracis, a gram positive rod. It is primarily caused by contact with infected wild or domestic animals or their products (such as wool). This organism has 3 clinical forms: inhalation, gastrointestinal and cutaneous. The primary lesion is a “malignant pustule” which begins as a painless papule that evolves into a hemorrhagic bulla. Ultimately, a black eschar forms. The lack of pain is helpful in distinguishing between anthrax and other infections of the skin which are painful, such as ecthyma. The other listed organisms are not causes of this disease.

Question 121

121- A patient with known chronic Hepatitis C virus infection presents with hyperkeratotic plaques of the bilateral feet. Biopsy reveals psoriasiform changes with superficial epidermal necrosis. Diet supplementation with what mineral has been shown to improve the appearance and symptoms of this cutaneous finding?

A. Zinc
B. Biotin
C. Magnesium
D. Calcium
E. Chromium

Answer 121

►A

Necrolytic acral erythema is characterized by hyperkeratotic well-defined plaques on the lower extremities, seen occasionally in patients with hepatitis C virus infection. Treatment consists primarily of treating the underlying infection. Diet supplementation with zinc has been shown to improve necrolytic acral erythema, even in the presence of normal serum zinc levels.

Question 122

122 -A patient is experiencing posterior cervical lymphadenopathy and has been diagnosed with African trypanosomiasis. This sign is known as:

A. Winterbottom’s sign
B. Hutchinson sign
C. Romana’s sign
D. Sleeping sickness sign
E. Tsetse sign

Answer 122

►A

This patient has African trypanosomiasis. It is caused by T. brucei gambiense and T. brucei rhodesiense and the vector is the Tsetse fly. Posterior cervical lymphadenopathy is known as winterbottom’s sign. Romana’s sign is eyelid edema and conjunctivitis at the site of inoculation for American trypanosomiasis.

Question 123

123- Which of the following is true regarding lymphogranuloma venereum?

A. The primary stage presents as a painful herpetiform ulcer.
B. Proctocolitis can be seen in the late stages of this disease.
C. It is caused by Chlamydia psittaci.
D. Buboes should be incised and drained.
E. Transmission does not occur via skin-to-skin contact.

Answer 123

►B

Lymphogranuloma venereum presents as a painless ulcer and is caused by Chlamydia trachomatis serotypes L1, L2, L3. While buboes can be aspirated, they should not be incised and drained. Transmission occurs through sexual contact, but can occur via skin-to-skin contact. Complications of late stage disease include proctocolitis, perirectal abscesses, rectovaginal fistulas, and anal fistulas.

Question 124

124- Which of the following tests is the most sensitive serologic test in late primary syphilis?
A. FTA-ABS
B. VDRL
C. ELISA
D. RPR
E. MHA-TP

Answer 124

►A

The fluorescent treponemal antibody absorption test is the most sensitive serologic test in primary syphilis. The ELISA is the test of choice in early primary and congenital syphilis because it is the first to become reactive. However, it is less sensitive in late primary syphilis because of reduction of IgM production. The ELISA is 100% specific. MHA-TP is less sensitive than FTA-ABS during primary syphilis.
Syphilis can be detected during the early infectious stages by taking swabs of the chancre for polymerase chain reaction (PCR). Dark-field microscopy examination of tissue or tissue fluid from a primary ulcer (chancre) or condylomata lata is now less commonly undertaken than in the past. Blood for serological tests is necessary for diagnosis. Serological tests turn positive about 5 to 6 weeks after acquiring the infection. In some cases, cerebrospinal fluid can be tested to confirm neurosyphilis.
Non-specific non-Treponemal tests eg Rapid plasma reagin (RPR), Venereal disease research laboratory (VDRL) May cross-react resulting in low-level false-positive tests during pregnancy, other infections, drug abuse, connective tissue disease and aging. Levels usually relate to disease activity and are used for monitoring treatment. After effective treatment of syphilis, these tests usually become negative but in some people, may remain positive at low levels
Specific anti-treponemal antibody tests eg Treponenam pallidum particle agglutination assay (TPPA), enzyme immunoassays (EIA or AIA), fluorescent treponemal antibody absorption (FTA- ABS), microhaemagglutination assay (MHA-TP) and Western Blot (WB). These detect antibody due to past or present infection with T. pallidum or another Treponema species (eg yaws or pinta) They cannot distinguish between different types of Treponemal infection eg yaws or syphilis

or the duration of infection. Most people with reactive treponemal tests will continue to have reactive tests for the remainder of their lives, regardless of treatment or disease activity. An EIA test is sometimes used as a screening test, as it avoids the false positives found when RPR or VDRL are used.Skin biopsy may or may not show characteristic histopathological features. Molecular testing using polymerase chain reaction (PCR) can confirm the presence of genetic material from the bacteria in ulcers, on the skin surface, in blood, lymph nodes and other tissue.

Reference: Forrestel AK, Kovarik CL, Katz KA. Sexually acquired syphilis: Laboratory diagnosis, management, and prevention. J Am Acad Dermatol. 2020 Jan;82(1):17-28. doi: 10.1016/ j.jaad.2019.02.074. Epub 2019 Apr 12. Review. PMID: 30986474

Question 125

125- A 16 year old female presents with a sore throat, painful cervical lymphadenopathy, and an enlarged spleen. An empiric trial of amoxicillin leads to the development of a diffuse morbilliform rash. What is the incubation period of the most likely viral cause of this patient’s symptoms?

A. 3-7 days
B. 7-10 days
C. 2-3 weeks
D. 3-7 weeks
E. 6 months

Answer 125

►D

Infectious mononucleosis is characterized by a sore throat, painful lymphadenopathy, fatigue, and splenomegaly. The formation of a morbilliform rash upon challenge with ampicillin or related antibiotics is a classic finding. The most common virus associated with infectious mononucleosis is Epstein-Barr virus. The incubation period is relatively long, 3-7 weeks.

Question 126

126- A 39 year old male goatherder presents with a necrotic eschar which is found to be caused by cutaneous anthrax. Bacillus anthracis produces edema factor, which causes gelatinous edema of skin by lesions by increasing what?

A. Cyclic adenosine monophosphate
B. Tumor necrosis factor alpha

C. Interleukin-1 beta
D. Transforming growth factor
E. Endothelial growth factor

Answer 126

►A

Edema factor is a portion of the edema toxin, one of two exotoxins secreted by Bacillus anthracis. Edema factor causes gelatinous edema of anthrax skin lesions by inducing an increase in cyclic adenosine monophophate levels. Lethal toxin, the other exotoxin, works by releasing tumor necrosis factor-alpha and interleukin-1 beta.

Question 127

127- A 20-month old child develops a high fever followed 2 days later by a sudden eruption of rose pink macules and papules with white halos as the fever subsides. What is the most likely diagnosis?

A. Measles
B. Rubella
C. Scarlet fever
D. Exanthem Subitum
E. Erythema infectiosum

Answer 127

►D

The cutaneous features of Exanthem Subitum (Roseola infantum, Sixth Disease)as described in the question develop as the fever subsides. While the other diagnoses are part of the differential diagnosis of “fever and rash” in children, only roseola infantum has this characteristic clinical course.

Question 128

128- A 69 year old man who had recently returned from a boating trip in the Atlantic developed pain with hemorrhagic bullae of his right leg. He had substained a cut on his right leg prior to leaving for the trip, but swam in the water anyway. Which of the following treatments should be started?

A. Doxycycline
B. Erythromycin

C. Penicillin
D. Rifampin
E. Dapsone

Answer 128

►A

The case presentation describes an infection with Vibrio vulnificus, a Gram-negative rod, which may lead to a rapidly expanding cellulitis, with hemorrhagic bullae and necrosis, and lifethreatening septicemia. This infection mainly occurs along the Atlantic seacoast. It may be acquired after ingesting raw oysters or other seafood. Alternatively, localized skin infection may result after exposure of an open wound to seawater. Doxycycline together with ceftazidime is the treatment of choice. In patients with preexisting hepatic dysfunction or immunocompromise and whose wounds are exposed to or acquired in saltwater, prophylactic antibiotic coverage with doxycycline, 100 mg every 12 h, and cleansing with 0.025% sodium hypochlorite solution may prevent progressive infection.

Question 129

129- Which of the following is not a tick born disease?

A. Lyme disease
B. Tularemia
C. Rocky Mountain spotted fever
D. Yaws
E. Ehrlichiosis

Answer 129

►D

Ticks are capable of transmitting:Lyme disease-Borrelia burgdorferi, a tickborne spirochete. Tularmia-Francisella tularensis, bite of a tick. Rocky Mountain spotted fever-Rickettsia rickettsii, tick typhus. Yaws-Treponema Palladium, subspecies pertunue-transmitted nonsexually, by contact with infectious lesions. Ehrlichiosis-Ehrlichia chaffeensis, tickborne

Question 130

130 -Herpetic whitlow is usually a localized infection to the index finger. The most common cause of Herpetic whitlow is from:

A. HSV2
B. HSV1
C. EBV
D. CMV
E. VZV

Answer 130

►A

Herpetic whitlow is more commonly caused by HSV2 from digital/genital contact. It can also occur in dentist.

Question 131

131- A patient with atopic dermatitis presents with frequent flares of dermatitis. They have multiple lichenified plaques, some with serum crust. Which of the following organisms is most likely colonizing these areas?

A. Aerobic diphtheroids
B. Gram positive coagulase negative cocci
C. Staphylococcus epidermidis
D. Staphylococcus aureus
E. Propionibacterium avidum

Answer 131

►D

S. aureus rapidly becomes a member of the cutaneous flora in locations where there is serum or plasma on the skin. Often patients with atopic dermatitis will have colonization of this organism in lesions and may benefit from topical or oral antibiotics. P. avidum and aerobic diphtheroids are present in moist regions of the skin. Gram positive coagulase negative cocci are the dominant organism in the dry regions of the body. S. epidermidis is most commonly found in oily body regions.

Question 132

132- Focal epithelial hyperplasia (Heck‟s Disease) is associated with which of the following human papillomavirus types?

A. 3
B. 4
C. 7
D. 10
E. 13

Answer 132

►E

Focal epithelial hyperplasia is caused by HPV-13 and 32.

Question 133

133 -A 23 year old intravenous drug user presents with the onset of purpura on the legs. Biopsy reveals vasculopathic changes with intravascular thrombi seen in superficial dermal vessels. Serum studies for cryoglobulins and Hepatitis C virus are both positive. Patients with HCV and mixed cryoglobulinemia are more likely to develop what malignancy?

A. Non-Hodgkins lymphoma
B. Cutaneous T-cell lymphoma
C. Anaplastic large cell lymphoma
D. Kaposi’s sarcoma
E. Acute myelocytic leukemia

Answer 133

►A

Mixed cryoglobulinemia is characterized by LCV and the finding of monoclonal or polyclonal IgG and IgM cryoglobulins in the blood. Mixed cryoglobulinemia is commonly associated with HCV infection. Patients with HCV-associated mixed cryoglobulinemia are at an increased risk of developing non-Hodgkins lymphoma, approximately 35 times the general population.

Question 134

134- Cat scratch disease is caused by infection with:

A. Bartonella species
B. Gram-positive cocci
C. Gram-positive bacilli
D. Rickettsiae
E. Spirochetes

Answer 134

►A

Cat scratch disease is caused by infection with B. henselae - a gram-negative bacillus of the genus Bartonella.

Question 135

135- Guarnieri bodies are associated with:

A. Measles
B. Orf
C. CMV
D. Smallpox
E. Anthrax

Answer 135

►D

Guarnieri bodies are cytoplasmic eosinophillic inclusions found on light microscopy.

Question 136

136 -A patient from India presents with fever, hepatosplenomegaly, and darkening of the skin. Which of the following is a cause of visceral leishmaniasis?

A. L. donovani
B. L. major
C. L. mexicana
D. L. aethiopica
E. L. tropicana

Answer 136

►A

Visceral leishmaniasis is the most severe form of leishmaniasis. Complications can be fatal, and include pneumonia, tuberculosis, and dysentery, which are potential opportunistic infections. Visceral leishmaniasis is most commonly caused by L. donovani and L. infantum.

Question 137

137- Which of the following factors is most important in the skin providing protection against infectious agents?

A. The mechanical barrier of intact skin
B. The resident flora present on intact skin
C. The relative dryness of intact skin
D. The cornified cell envelope
E. The presence of immunoglobulins on intact skin

Answer 137

►A

The most important determinant of the skin‟s protection against infectious agents is the mechanical barrier of intact skin. The dryness of the skin is also important in retarding infection. The resident flora may help prevent colonization by pathogenic organisms, but is not the most important factor. Immunoglobulins are present on intact skin in miniscule amounts. The cornified cell envelope is not a major determinant of infection prevention.

Question 138

138- Which exotoxin(s) are involved in mediating the effects of Bacillus anthracis - the causative organism for anthrax?

A. Exotoxin B
B. Edema Toxin
C. Alpha toxin
D. Lethal Toxin
E. Edema Toxin and Lethal Toxin

Answer 138

►E

B. anthracis has 2 exotoxins: edema toxin and lethal toxin, each comprised of a pair of noncovalently linked proteins: “ Edema toxin = Edema Factor (EF) + Protective Antigen (PA) “ Lethal toxin = Lethal Factor (LF) + PA “ EF causes gelatinous edema of anthrax skin lesions by inducing an increase in cyclic adenosine monophosphate (cAMP) levels “ LF causes shock and death in disseminated anthrax via the release of tumor necrosis factor-alpha (TNF-a)and interleukin-1b (IL-1b) “ PA is responsible for entry of exotoxins into the cell by receptormediated endocytosis.

Question 139

139- A rabbit farmer presents with fevers, myalgia, and a rash. A serum study reveals antibodies to Francisella tularensis. Which of the following is the most common form of tularemia?

A. Ulceroglandular
B. Chancriform
C. Oculoglandular
D. Typhoidal
E. Meningeal

Answer 139

►A

Tularemia represents a wide range of clinical syndromes caused by Francisella tularensis. The bacterium is most commonly acquired through contact with infected animals, including rabbits. There are a wide variety of variants, with the ulceroglandular form being most common. Ulceroglandular tularemia is characterized by a chancre-like ulcer with raised borders and regional lymphadenopathy, most commonly on the finger or hand. Treatment is with streptomycin.

Question 140

140- Which human papillomavirus type is associated with giant condylomata of Bushke and Lowenstein (Bushke-Lowenstein tumor)?

A. 1
B. 2
C. 6
D. 16
E. 31

Answer 140

►C

The Bushke-Lowenstein tumor is caused by HPV-6 and 11.

Question 141

141. A- 48 year-old man develops headache, myalgias, and high fever 5 days after a hunting trip. On examination he has a tender ulcer with raised margins and an eschar on his index finger, as well as tender axillary lymphadenopathy. The most likely diagnosis is:

A. Anthrax
B. Orf
C. Glanders
D. Tularemia
E. Erysipeloid

Answer 141

►D

Tularemia, which is caused by Francisella tularensis, occurs after exposure to infected animals, including, rabbits, foxes, and squirrels. The clinical description is that of the ulceroglandular form, which is the most common presentation.

Question 142

142- The treatment of choice of the tropical infectious disease shown is:

A. Ivermectin
B. Permethrin
C. Diethylcarbamazine
D. Pentavalent antimony
E. Mebendazole

Answer 142

►D

The ulcerated nodule shown here is characteristic Leishmaniasis is treated with pentavalent antimony. of cutaneous leishmaniasis (CL).

Question 143

143- A homeless patient with a history of diabetes and alcoholism presents with chronic suppurative nodules with granular bodies on light microscopy. Culture rapidly grows Staphylococcus aureus colonies. What is the clinical term describing this type of infectious lesion?
A. Botryomycosis
B. Scrofuloderma
C. Rhinoscleroma
D. Ecthyma gangrenosum
E. Erysipeloid

Answer 143

►A

Chronic purulent nodules with granular bodies seen in patients with immunosuppresion, diabetes, and alcoholism is called botryomycosis. Causative organisms include S. aureus, P. aeruginosa, E. coli, and Proteus species. Scrofuloderma is cutaneous extension of underlying Mycobacteria tuberculosis infection. Rhinoscleroma is caused by Klebsiella pneumoniae rhinoscleromatis. Ecthyma gangrenosum is typically seen following Pseudomonas septicemia. Erysipeloid is caused by Erysipelothrix rhusiopathiae.

Question 144

144- Corynebacterium tenuis is responsible for which of the following infections?

A. Majocchi’s granuloma
B. Trichomycosis axillaris
C. Erysipelas
D. Malakoplakia
E. Erysipeloid

Answer 144

►B

Corynebacterium tenuis is responsible for causing trichomycosis axillaris, a superficial bacterial overgrowth of axillary hairs characterized by circumferential yellow (most common), red, or black granular concretions. Majocchi’s granuloma is a dermatophyte infection. Erysipelas is caused by beta-hemolytic group A streptococcus. Malakoplakia is usually caused by S. aureus, P. aeruginosa, or E. coli. Erysipeloid is caused by Erysipelothrix rhusiopathiae. Corynebacterium minutussimum is the causative organism in erythrasma and pitted keratolysis.

Question 145

145- A 32 year-old woman presents with meningitis and palpable purpura. A diagnosis of meningococcemia is confirmed via culture of cerebrospinal fluid. Which complement components are most likely to be deficient in this patient?
A. C1
B. C2
C. C3
D. C4
E. C5

Answer 145

►E

Patients with meningococcemia often demonstrate deficiencies of late complement components C5-9.

Question 146

146- Trichomycosis axillaris has a yellowish brown concretions on axillary hair shaft and is caused by:
A. Corynebacterium tenuis
B. Francisella tularensis
C. Epstein-Barr Virus
D. Staphylococcal aureus
E. Micrococcus sedenatrius

Answer 146

►A

Trichomycosis axillaris is caused by Corynebacterium tenius. It is a yellowish brown concretions on axillary hair shafts. Treatment is shaving, benzoyl peroxide gel, and topical erythromycin.

Question 147

147- What is the vector for this nematodal infection?

A. Water flea (Cyclops)
B. Tsetse fly (Glossine morsitans)
C. Reduviid bug
D. Mango fly (Chrysops)
E. Black fly (Simulium)

Answer 147

►D

Loiasis is caused by the nematode loa loa. It is transmitted by the mango fly (Chrysops dimidia or CHrysops silacea). It may manifest with painful, localized subcutaneous nonpitting edema called calabar swellings. Conjunctival migrations are also common.

Question 148

Human bites result in infection with this gram negative bacillus that is the part of the normal flora of the human mouth. The infection can also follow fist fights from blows to the mouth. The infection is caused by:

A. Eikenella corrodens
B. Bartonella hensalae
C. Pastuerella mutocida
D. Pseudomonas
E. Crotalidae

Answer 148

►A

Eikenella corrodens is common in human bite infections. Pasteurella multocida is usually from cat bites and Pasteurella canis is from dog bites.

Question 149

149- A patient is suspected to have contracted rabies after a dog bite. The best site for diagnostic biopsy would be:

A. Neck
B. Acral area
C. Site of bite
D. Buccal mucosa
E. Buttocks

Answer 149

►A

The best site for diagnosis of rabies is a biopsy from the neck. This virus has an incubation period of 5 days to 1 year and demonstrates retrograde axoplasmic flow until it reaches the spinal cord. It subsequently undergoes centrifugal spread along the peripheral nerves to the skin, intestine, and into the salivary glands where it is shed.

Question 150

150 -What is the annual risk of developing herpes zoster in an HIV infected patient?

A. 3% per month
B. 10% per month
C. 3% per year
D. 10% per year
E. 25% per year

Answer 150

►C

The annual risk of developing herpes zoster in an HIV infected individual, regardless of the CD4 count, is approximately 3%.

Question 151

151- A 59-year-old male returns from traveling abroad where he ate many fish. Since then he complaints of recurring migratory 1 cm/day erythematous urticarial plaques. Biopsy shows eosinophilic panniculitis. What is the most likely condition?

A. Drancunculiasis
B. Gnathostomiasis
C. Enterobiasis
D. Hookworm
E. Larva currents

Answer 151

►B

This patient has gnathostomiasis caused by Gnathostoma dolorosi or spinigerum. It is commonly acquired from freshwater fish. It manifests with migratory intermittent erythematous urticarial

plaques that recur every 2-6 weeks. The plaques move about 1 cm/day. Histology shows eosinophilic panniculitis. Treatment is surgical removal or albendazole.

Question 152

152- Foamy macrophages containing Klebsiella pneumoniae are called:

A. Virchow cells
B. Hansemann’s cells
C. Mikulicz’s cells
D. Michaelis-Gutman cells
E. Russell cells

Answer 152

►C

Mikulicz”s cells are foamy macrophages found in Rhinoscleroma “ a chronic, inflammatory, granulomatous disease of the upper respiratory tract. Virchow cells are found in Hansen”s disease. Hansemann cells and Michaelis-Gutman bodies are found in Malakoplakia.

Question 153

153- A 37 year old male with a history of HIV/AIDS presents complaining of the new onset of purplish nodules of the feet and lower legs. He lost his insurance eight months ago and has been unable to afford the HAART therapy that he was prescribed. HHV-8 is found in the semen of what percent of men with this disease?

A. 5%
B. 20%
C. 35%
D. 50%
E. 65%

Answer 153

►B

Kaposi’s sarcoma is a vascular neoplasm seen most commonly on the lower extremities, back, and genitaliae. In the United States, this disease is most commonly seen in patients with AIDS. Kaposi’s

sarcoma has been linked to infection with HHV-8. 20% of men with Kaposi’s sarcoma will have detectable HHV-8 in their semen.

Question 154

154- Which bacterial disease carries a risk of mortality due to coinfection with salmonella?

A. Carrion’s disease
B. Cat-scratch disease
C. Trench fever
D. Rocky Mountain Spotted Fever
E. Q fever

Answer 154

►A

Carrion’s disease, or Oroyo fever, is caused by Bartonella bacilliformis and is transmitted via the Lutzomyia sandfly. It is characterized by fevers, headache, arthralgias, and an acute eruptive stage that resembles bacillary angiomatosis. It has an untreated fatality rate of 40% secondary to salmonella infection; chloramphenicol is given with tetracycline for treatment. Epidemic typhus may also coexist with salmonella.

Question 155

155- Xenopsylla cheopis is the vector responsible for which infectious disease?

A. Human Monocytic Ehrlichiosis
B. Human Granulocytic Ehrlichiosis
C. Scrub typhus
D. Epidemic typhus
E. Endemic typhus

Answer 155

►E

Xenopsylla cheopis (rat flea) is the vector of endemic typhus, which is caused by R. typhi.

Question 156

156- A 25 year old woman who is 13 weeks pregnant is exposed to cytomegalovirus (CMV). Three weeks later, she develops infectious mononucleosis symptoms. What percentage of neonates with congenital CMV infection are asymptomatic?

A. 10%
B. 25%
C. 50%
D. 75%
E. 90%

Answer 156

►E
Symptoms of congenital CMV infection include low birth weight, microcephaly, seizures, petechial rash, and hepatosplenomegaly. Fortunately, the vast majority (90%) of congenital CMV infections are asymptomatic.

Question 157

157- Which of the extracellular enzymes of S. aureus plays a role in toxic shock syndrome (TSS)?

A. Coagulase
B. Penicillinase
C. Enterotoxin
D. Hemolysin
E. Exfoliatin

Answer 157

►C

In addition to TSST-1 which is present in 50% of non-menstrual cases of TSS, enterotoxins, especially B & C, cause TSS. These enterotoxins are also superantigens, which recognize the V
-beta region of the T-cell receptor. Coagulase clots plasma, Penicillinase degrades penicillin, Hemolysin lyses red blood cells and exfoliatin splits the epidermis (antigen is desmoglein 1).

Question 158

158- A patient with primary syphilis is treated with Benzathine penicillin G. Soon after treatment, he develops fever, headache, myalgias, and elevated white blood cell count, consistent with the

Jarisch-Herxheimer Reaction. This reaction is primarily mediated through which inflammatory cytokine?

A. TNF-alpha
B. IFN-gamma
C. IL-6
D. EGFR
E. IL-10

Answer 158

►A

The Jarisch-Herxheimer Reaction is characterized by fever, headache, lymphadenopathy, myalgias, and elevated white blood cell count. It is caused by the release of inflammatory cytokines, particularly TNF-alpha, due to phagocytosis of spirochetes following antibiotic administration.

Question 159

159 -A 23 year old Peace Corp volunteer returns from Africa with an extensive undermined, nonhealing ulceration on the right lower leg. Which of the following infections is the most likely cause of this presentation?

A. M. marinum
B. M. kansasii
C. M. chelonei
D. M. ulcerans
E. Leishmania donovani

Answer 159

►D

The most likely cause of a non-healing ulceration in someone who has been in a tropical location is
M. ulcerans. M. marinum causes inflammatory nodules following injury in an aquatic environment.
M. chelonei is a rapidly growing organism most commonly found in soil, water, dust and animals which presents as single/multiple erythematous SC nodules on an extremity or following a surgical procedure. M. kansasii rarely causes skin lesions. L. donovani is a causse of visceral leishmaniasis in India and Kenya (kala-azar).

Question 160

160- Calabar swellings are a characteristic feature of which disease?

A. Onchocerciasis
B. Eumycetoma
C. Tertiary Syphilis
D. Carrion’s Disease
E. Loiasis

Answer 160

►E

Calabar swellings are characteristic of Loiasis. They are transient, non-tender soft tissue swellings found most commonly around joints.

Question 161

161- A 8 year-old girl presents to the pediatrician with a poorly marginated blue-red single indurated plaque on her right cheek. What is the most likely causative organism?

A. Beta-hemolytic group A streptococcus
B. Staphyloccus aureus
C. Pseudomonas aeruginosa
D. Haemophilus influenzae
E. Klebsiella pneumoniae

Answer 161

►D

The most likely diagnosis is H. flu cellulitis. This infection usually occurs in children and is characterized by a single indurated plaque with poorly delineated margins. Erysipelas, an infection caused by beta-hemolytic streptococcus group A, usually presents with well delineated margins in adult patients.

Question 162

162- Which virus is most commonly associated with oral hairy leukoplakia?

A. Pox virus
B. Herpes virus

C. Epstein-Barr virus
D. Human papilloma virus
E. Parvovirus

Answer 162

►C

Oral hairy leukoplakia is an oral mucosal infection most often caused by the Epstein-Barr virus, which occurs in immunocompromised patients. Clinically, thick, white plaques are noted on the lateral sides of the tongue, often fissured.

Question 163

163 -A 29-year-old woman presents with multiple crateriform pits on the soles of her feet following a month of hiking on the Appalachian Trail. She wants a complete skin exam and wonders about her feet. Which of the following do you plan to do next for her foot problem.

A. These pits are a variant of normal
B. You explain that she has a hereditary syndrome that causes these pits
C. You explain that this is a superficial bacterial infection and will resolve with topical therapy
D. You ask for a skin biopsy
E. You use a Wood‟s lamp to confirm your diagnosis

Answer 163

►C

Multiple crateriform pits on the feet following suboptimal hygiene most likely is pitted keratolysis caused by Micrococcus sedentarius. Treatment is topical erythromycin, clindamycin or benzoyl peroxide. This is not Gorlin‟s syndrome (Basal Cell Nevus syndrome). While these pits are common, it is not a variant of normal. A skin biopsy could confirm the diagnosis, but is not necessary. A Wood‟s lamp would not be particularly helpful. Some believe that Corynebacterium spp. also cause this condition, but that is still theory and not proven.

Question 164

164- Roseola infantum is caused by which virus?

A. Coxsackie virus A16

B. Human herpes virus 6
C. Parvovirus B19
D. Epstein-Barr virus
E. Pox virus

Answer 164

►B

Roseola infantum may be cause be either human herpes virus types 6 or 7. It is the sixth of the traditional exanthems of childhood. A diffuse, maculopapular eruption is typically preceded by a prodrome of fever and either respiratory or gastrointestinal symptoms. The infection usually occurs in the spring and the fall and nearly all children are seropositive for the virus by the age of 4.

Question 165

165- Butcher’s warts are most commonly caused by which human papilloma virus (HPV) type?

A. 7
B. 2
C. 3
D. 5
E. 13

Answer 165

►A

Butcher’s warts are caused by HPV type 7.

Question 166

166- For which of the following smallpox vaccination complications is the administration of vaccine immune globulin indicated?

A. Post-vaccinal encephalitis
B. Erythema multiforme
C. Eczema vaccinatum
D. Vaccinia keratitis
E. Mild generalized vaccinia

Answer 166

►C

Vaccinia immune globulin can be administered to treat some of the complications associated with vaccinia vaccination. Vaccinia immune globulin is indicated for inadvertent inoculation with extensive involvement or ocular implantations, eczema vaccinatum, generalized vaccinia (severe or recurrent), and progressive vaccinia. It is not recommended for inadvertent inoculation with mild reaction, generalized vaccinia (mild or limited), post-vaccination encephalitis, and isolated vaccinia keratitis.

Question 167

167- Nonmenstrual cases of the staphylococcal toxic shock syndrome are mediated by which of the following toxins?

A. Enterotoxins B and C
B. Exfoliative toxins A and B
C. Edema toxin
D. Epidermolytic toxins A and B
E. Pyrogenic exotoxins A, B, C

Answer 167

►A

Toxic shock syndrome (TSS) is mediated by Enterotoxins B and C (50% of nonmenstrual cases) and TSS toxin 1 (TSST-1), which is the leading cause of menstrual cases.

Question 168

168- Which of the following skin manifestations of M. tuberculosis infection is a tuberculid?

A. Erythema induratum of Bazin
B. Lupus vulgaris
C. Miliary TB
D. Scrofuloderma
E. Tuberculous gumma

Answer 168

►A

A tuberculid is a cutaneous immunologic reaction to tuberculosis elsewhere in the body. By definition, cultures and stains for M. tuberculosis are negative. Erythema induratum of Bazin/Nodular vasculitis present as erythematous or cyanotic nodules on the posterior calves. 85% of cases occur in women. The other listed presentations of TB are all due to secondary spread from an established TB infection at another location. In some cases, organisms can be recovered and cultures may be positive.

Question 169

The treatment for patients that are pregnant or for children <9 for lyme disease is:

A. Doxycycline
B. Levoquin
C. Amoxicillin
D. Tetracycline
E. Penicillin

Answer 169

►C

Patients that are pregnant or for children <9 years old, the treatment for lyme disease is amoxicillin. Lyme disease is caused by B. burgdorferi. Clinical signs are erythema migrans and acrodermatitis chronica atrophicans.

Question 170

170 -A 35 year old male has had frequent sex with prostitutes. He presents complaining of the rapid onset of a new rash on his legs. A review of symptoms is otherwise unremarkable. Examination reveals palpable purpura and tender nodules of the lower legs. Biopsy reveals vasculitis of small- and medium-sized vessels. What percentage of patients with this disease are found to be infected with Hepatitis B virus?

A. 7-8%
B. 20%
C. 35%
D. 1%
E. 50%

Answer 170

►A

Polyarteritis nodosa is characterized by the onset of painful nodules on the lower extremities. It can be limited to the skin (cutaneous PAN), or can involve a wide variety of organ systems (systemic PAN). Approximately 7-8% of cases of polyarteritis nodosa cases are associated with Hepatitis B virus infection.

Question 171

171- A 43 year-old man presents with suppurative nodules and sinus tracts over the mandible. He also is noted to have poor oral hygiene. What is the most likely causative organism?

A. Bartonella Henselae
B. Nocardia brasilensis
C. Streptococcus somaliensis
D. Actinomyces israelii
E. Staphylococcus aureus

Answer 171

►D

Actinomyces israelii is an anaerobic gram-positive rod which causes chronic suppurative nodules and sinus tracts with an exudate containing sulfur granules. It most commonly effects the cervicofacial area, especially near the mandible. The abdomen and thoracic areas can also be affected. The source of infection is endogenous and patients with poor oral hygiene, penetrating foreign bodies, and recent dental procedures are at increased risk. Treatment of choice is penicillin.

Question 172

172- A young male patient presents with a painful ulcer with a ragged edge after a new sexual encounter. What is the treatment of choice?

A. Penicillin
B. Doxycycline
C. Azithromycin
D. Ciprofloxacin
E. Cephalexin

Answer 172

►C

Ulcers in the genital area in sexually active patient generally fall into two groups: painful and painless. Painless ulcers include syphilllis, lymphogranuloma venereum, and granuloma inguinale. The primary cause of painful erosion or ulcer is H. ducreyi or herpes simplex. An ulcer with a ragged edge that is painful is characteristic of H. ducreyi. The treatment of choice is azithromycin.

Question 173

173- A 35 year-old woman presents with a painful vaginal erosion and tender left-sided inguinal lymphadenopathy. Gram stain reveals clusters of coccobacilli in a “school of fish” pattern. What is the most likely diagnosis?

A. Primary syphilis
B. Lymphogranuloma venereum
C. Granuloma inguinale
D. Chancroid
E. Secondary syphilis

Answer 173

►D

Chancroid classically presents with a soft, tender chancre with ragged edges and unilateral, tender inguinal adenopathy (bubo). A “school of fish” pattern on Gram or Giemsa stain is diagnostic.

Question 174

174- Botryomycosis is:

A. A fungal infection caused by M. canis
B. A bacterial infection commonly associated with Clostridium botulinum
C. A bacterial infection commonly associated with Staphylococcus aureus
D. A fungal infection caused by T. tonsurans
E. An acute, disseminated infection involving the genitourinary system

Answer 174

►C

Botryomycosis is an uncommon, chronic, idonlent disorder characterized by nodular, crusted, purulent lesions. Sinuses that discharge sulfur granules are present. These heal with atrophic scars. The granules yield most commonly Staphylococcus aureus on culture, although cases caused by Pseudomonas aeruginosa, E. coli, Proteus, Bacteroides, and Streptococcus have been reported

Question 175

175- Which of the following is not a DNA virus?

A. Herpesvirus
B. Poxvirus
C. Parvovirus
D. Paramyxovirus
E. Adenovirus

Answer 175

►D

Paramyxovirus is a single-stranded RNA virus. All other listed choices are DNA-based viruses.

Question 176

176- A patient is diagnosed with a unilateral enlargement of the medial clavicle after being diagnosed with congenital late syphilis. This is called the:

A. Higoumenaskis sign
B. Hutchinson’s sign
C. Saber sign
D. Saddle sign
E. Gummas

Answer 176

►A

This patient has congenital late syphilis, seen in children over two years of age. The unilateral enlargement of the medial clavicle is called the Higoumenaki’s sign. These patients also can have Hutchinson’s teeth or widely-spaced, peg-shaped teeth in the upper incisors. They can also have a saddle nose and saber shins.

Question 177

178- Histoplasmosis is a self limiting pulmonary disease that is related to the dose of conidia and can be seen in AIDS and immunosuppressed patients. It is associated with:

A. Bird and bat droppings
B. Rat droppings
C. Deer droppings
D. Deer mites
E. Tic bites

Answer 177

►A

Histoplasmosis is associated with bird and bat droppings and is seen in the mississippi and ohio river valleys in conjunction with inhalation of microconidia.

Question 178

179- A patient with HIV/AIDS presents complaining of an asymptomatic patch on the tongue. Examination reveals a white patch with a corrugated surface on the lateral tongue. What percentage of HIV patients will have this finding?

A. 5%
B. 20%
C. 33%
D. 50%
E. 67%

Answer 178

►C

Oral hairy leukoplakia is characterized by a white patch with a corrugated surface on the side of the tongue. It is generally asymptomatic. Oral hairy leukoplakia is seen most commonly in patients with defective cell-mediated immunity, in particular HIV infection. Oral hairy leukoplakia is associated with EBV opportunisitc infection, among other viruses. 33% of patients with HIV will have oral hairy leukoplakia.

Question 179

180 -The vector of New World Leishmaniasis is the:

A. Phlebotomus sandfly
B. Lutzomyia sandfly
C. Tsteste fly
D. Deer fly (Chrysops spp.)
E. Simulium black fly

Answer 179

►B

The sandfly belonging to the genus Lutzomyia is the vector of New World Leishmaniasis. Sandflies of the genus Phlebotomus are the vectors of Old World Leishmaniasis.

Question 180

181- A 34 year old woman complains of recurrent painful blisters on her lower lip. These occur 4 times per year, and are preceded by painful sensations for a day before the blisters appear. What is the most common trigger of recurrent orolabial herpes simplex virus infection?

A. UVB radiation
B. UVA radiation
C. Visible light radiation
D. Emotional stress
E. Medication use, including opioids

Answer 180

►A

Recurrent orolabial herpes simplex virus infection is a very common problem. In many cases, the cause of the recurrences is idiopathic. Identifiable triggers include light exposure and emotional stress, among others. UVB is the most commonly implicated factor.

Question 181

182- Verruga peruana is transmitted by:

A. Tick
B. Blackfly
C. Sandfly
D. Fecal oral contact

E. Fecal fecal contact

Answer 181

►C

Verruga peruana, a disease endemic to Peru and a few neighboring countries, is caused by Bartonella bacilliformis. It is transmitted by the sandfly, Lutzomyia verrucarum. It is preceded by an acute febrile stage called Oroyo fever or Carrion”s disease. The treatment of choice is chloramphenicol.

Question 182

183- Which of the following is the vector of lymphatic filariasis caused by Wuchereria bancrofti?

A. Black fly
B. Tsteste fly
C. Mosquito
D. Deerfly
E. Botfly

Answer 182

►C

Lymphatic filariasis is spread by mosquitoes belonging to genera Aedes, Anopheles, Culex, or Mansonia.

Question 183

184- A patient is diagnosed with Loiasis. This patient most likely has clinical features such as:

A. Adult worm migrating across the conjunctivae
B. Nodules over bony prominences on the extremities
C. Ocular involvement that leads to blindness
D. Depigmented macules/patches also known as “leopard skin”
E. Pruritic papules

Answer 183

►A

Loiasis is caused by the organism Loa Loa. The vector is mango flies. The clinical characteristic is calabar swelling and adult worm migrating across conjunctivae or “eye worm”. The treatment is DEC or diethylcarbamazine.

Question 184

185- A patient on the bone marrow transplant service has a fever, neutropenia, hemorrhagic bullae and erythematous nodules with dusky gray centers. The organism most likely to be responsible is:

A. Streptococcus pyogenes
B. Mycobacterium tuberculosis
C. Candida albicans
D. Pseudomonas aeruginosa
E. Staphylococcus aureus

Answer 184

►D

Ecthyma gangrenosum is an infection of critically ill or immunocompromised individuals by Pseudomonas aeruginosa. Clinically, patients develop opalescent, tense vesicles or pustules surrounded by a narrow pink to violaceous halo. The lesions rapidly become hemorrhagic, then violaceous and necrotic leaving ulcers. The most common location is on the buttocks and lower extremities. Treatment is with aminoglycosides.

Question 185

186- What is the principal vector of Lyme Disease in the Northeastern U.S.?

A. Ixodes ricinus
B. Soft-bodied ticks (Ornithodoros)
C. Ixodes dammini
D. Ambylomma americanum
E. Dermacentor variabilis

Answer 185

►C

The proncipal vector of Lyme Disease in the Northeastern U.S. is Ixodes dammini (Ixodes scapularis).

Question 186

187- Patients that have diagnosed with congenital syphilis have dental findings called:

A. Hutchinson teeth
B. Erythrodontia
C. Hypodontia
D. Peg-shaped teeth
E. Enamel hypoplasia

Answer 186

►A

Congential sphyilis can be passed from the mother to the child. Dental findings are called hutchinson teeth and mulberry molars.

Question 187

188- Each of the following is true regarding leishmaniasis except:

A. Arthropod vector is the sand fly
B. Mazzotti‟s test is diagnostic
C. Pentavalent antimony used for visceral disease
D. Cutaneous disease is the most common form
E. Espundia seen mucocutaneous disease

Answer 187

►B

Leishmaniasis is a parasitic infection born by a sandfly vector. No treatment is necessary for cutaneous leishmaniasis, pentavalent antimony for visceral leishmaniasis and mucocutaneous. Mazzotti reaction is used to test for onchocerciasis in which a single dose of dimethycarbamazine is given for reaction. Amphotericin B is only used in pentavalent antimo ny resistant cases.

Question 188

189- All of the following are true regarding smallpox except:

A. Caused by variola virus
B. Transmitted by respiratory secretions
C. Virus is found in skin lesions

D. Vaccination is contraindicated in children under 5
E. Associated with thrombocytopenia

Answer 188

►D

Smallpox is an acute exanthematous infection caused by the variolae poxvirus. It is transmitted primarily by respiratory secretions as well as more infrequently skin inoculation and fomite spread. Following contact, there is an asymptomatic period of 12-13 days. Following the asymptomatic period, patients develop a prodrome of fever, headache, back pain and vomiting for 3 days. Then, the characteristic deep seated papules that vesicles appear. These lesions mature into a pustule with a central umbilication. Occasionally, patients may develop a hemorrhagic form of the disease which is associated with thrombocytopenia and poor prognosis. Vaccination is not contraindicated in children under 5.

Question 189

190- This type of syphilis has the clinical characteristic of widespread cutaneous eruptions, hamcolored macules on the palms and soles, moth eaten alopecia and condyloma lata.

A. Primary
B. Secondary
C. Tertiary
D. Latent
E. Congenital

Answer 189

►B

This is an example of secondary syphilis. It involves the skin and mucous membranes. It also lasts for 4 to 12 weeks. It involved widespread cutaneous eruptions, ham-colored macules on the palms and soles, mucous patches, condyloma lata, split papules and moth eaten alopecia.

Question 190

191- A 67 year old homeless man comes to clinic complaining of a painful lump along his lateral jawline which has been present for many months. He has noticed that it occasionally drains a purulent material. What is the most likely diagnosis?

A. Actinomyces israelii
B. Nocardia brasilensis
C. Actinomadura madurae
D. Streptomyces somaliensis
E. Mycobacteria tuberculosis

Answer 190

►A

Actinomycosis is a chronic suppurative infection forming nodules and sinus tracts with an exudate containing sulfur granules. Risk factors include poor oral hygiene, penetrating foreign bodies, and dental procedures. The causative organism is Actinomyces israelii, an anaerobic gram-positive rod.

Question 191

192- What are the three rapid grower mycobacteria and what is the current treatment of choice?

A. leprae, chelonae, abscessus; clarithromcyin
B. Tuberculum, abscessus, fortuitum; rifampin
C. Chelonae, asbcessus, fortuitum; clarithromycin
D. Lepra, fortuitum, abscessus; minocycline
E. Chelonae, absccessus, fortuitum; minocycline

Answer 191

►C

These three are rapid grower mycobacteria and the treatment of choice is clarithryomycin. Minocycline can also be used, but it considered second line in WHO treatment.

Question 192

193- All of the following are potential causes of a false positive RPR except:

A. Systemic Lupus Erythematosus (SLE)
B. Pregnancy
C. Malignant Melanoma
D. Lepromatous Leprosy
E. Malaria

Answer 192

►C

Non-treponemal tests for syphilis measure antibodies against phospholipids released from treponemes and damaged host cells. False positive non-treponemal tests can occur in the setting of pregnancy, autoimmune diseases, other spirochete infections, and infectious diseases such as leprosy and malaria. It does not occur in cases of melanoma.

Question 193

194- A 23 year old female patient is found to have genital warts. A referral to an gynecologist reveals that she has cervical dysplasia. What viral proteins does HPV use to induce neoplasia?

A. E6 and E7
B. E1 and E2
C. L1 and L2
D. E8 and L1
E. E3 and E4

Answer 193

►A

Certain HPV subtypes have been shown to induce neoplasia, including cervical cancer. There are many high-risk subtypes, including 16, 18, 31, and 33. The HPV early genes E6 and E7 bind the tumor suppressors p53 and retinoblastoma protein, respectively, inactivating them and initiating oncogenesis.

Question 194

195- A patient is given a single dose of dimethylcarbamazine and soon develop edema, itching, fever, arthralgias, and exacerbation of pruritus. He most likely has which underlying condition?

A. Onchocerciasis
B. Loiasis
C. Filariasis
D. Gnothostomiasis
E. Trichinosis

Answer 194

►A

This patient developed an acute reaction to dimethylcarbamazine indicating a Mazzotti reaction. This reaction is seen with onchocerciasis. Appropriate treatment for onchocerciasis, caused by Onchocerca volvulus, is ivermectin. These patients may demonstrate pruritus, dermatitis, leopard skin, onchocercomas (nodules with microfilariae) and blindness.

Question 195

196- How long is the life cycle for the mite that causes this infestation?

A. 1 day
B. 1 week
C. 1 month
D. 6 months
E. 1 year

Answer 195

►C

Scabies is caused by the mite Sarcoptes scabiei var. hominis. The life cycle of the mite is 30 days. A female mite will lay 60-90 eggs during her life.

Question 196

197 - Winterbottom‟s sign is a characteristic feature of which of the following diseases?

A. Leishmaniasis
B. Onchocerciasis
C. Loaiasis
D. African Trypanosomiasis
E. Strongyloidiasis

Answer 196

►D

Winterbottom‟s sign (posterior cervical lymphadenopathy) is a clinical feature of African trypanosomiasis. Romaña‟s sign (eyelid edema and conjunctivitis at site of incoculation) is a diagnostic finding in American trypanosomiasis (Chagas‟ disease).

Question 197

198- A 40-year-old male with HIV (CD4 <200) presents with asymptomatic, slowly enlarging yellowpink papules and nodules localized to his perianal skin. A skin biopsy is performed, which reveals foamy dermal interstitial histiocytes with characteristic basophilic laminated inclusion bodies. The latter are noted to stain positively with von Kossa, Perls, and PAS stains. The most likely diagnosis is:

A. eruptive xanthomas
B. malakoplakia
C. hidradenitits suppurtiva
D. granuloma inguinale
E. chancroid

Answer 197

►B

Malakoplakia is a multi-organ inflammatory granulomatous disease that most frequently arises in the setting of immunosuppression. Common sites of involvement include the genitourinary, lung, lymph nodes and bone. Cutaneous involvement is rare, and typically presents as asymptomatic papules, nodules, or plaques. Lesions may have associated erosions or ulcerations, and sinus tracts may be seen. While skin lesions are non-specific, histopathology reveals foamy dermal histiocytes known as von Hansemann cells which contain basophilic granular inclusions. The latter are known as Michaelis-Gutmann bodies and are considered pathognomonic for malakoplakia. Michaelis- Gutmann bodies are comprised of calcium, iron, and phosphate salts, and hence stain positively with von Kossa, Perls, and PAS, respectively. The pathophysiology of malakoplakia is thought to arise from an acquired defect in macrophage activation in response to bacterial infection, most commonly. E. coli. Treatment for cutaneous lesions is surgical excision, although recurrence is not uncommon.

Question 198

199 -Carrion’s disease is characterized by fevers, headaches and arthralgias and is accompanied by severe hemolytic anemia. Superinfection with which organism is the most frequent cause of death?

A. Bartonella bacilliformis
B. Bartonella henselae
C. Bartonella Quintana
D. Salmonella
E. Shigella

Answer 198

►D

Carrion’s disease (Oroya fever) is characterized by fevers, headaches and arthralgias and is accompanied by severe hemolytic anemia. Superinfection with Salmonella is the most frequent cause of death. Protection from sandfly bites is all-important.

Question 199

200- All of the following are true regarding tularemia except:

A. Caused by the gram negative Francisella tularensis
B. Ticks serve as a vector
C. No longer one of the CDC’s list of reportable diseases
D. Presents as an acute febrile illness
E. Potential for use as a biologic weapon

Answer 199

►C

Tularemia is a zoonotic disease caused by the gram-negative coccobacillus Francisella tularensis. It is transmitted by ticks: dog tick, wood tick, lone star tick, or from deer flies (Chrysops) or from contact with infected mammals (usually rabbits) or from infected water. It characteristically presents as an acute febrile illness with other variable clinical manifestations depending on the route of inoculation. Possible symptoms could include an ulcer at the site of inoculation, pharyngitis, ocular lesions, lymphadenopathy, and pneumonia. Diagnosis can be made by culture or a fourfold titer change. Because of its potential use as a biologic agent, tularemia is once again a reportable disease.

Question 200

201- The characteristics of tuberculoid leprosy or TT is:

A. Lepromin test +
B. IL4, IL-10,
C. Multibacillary
D. Lepromin test -
E. No loss of sensation or sweating

Answer 200

►A

Tuberculoid leprosy has a TH1 cytokine profile of IFN gamma, IL-2, IL-12. It is paucibacillary, Lepromin test +. There is less than 3 lesions and anesthetic and anhidrotic lesions.

Question 201

202- Exanthem Subitum is caused by which of the following?

A. Group A Steptococcus
B. Coxsackie virus
C. Human Herpes Virus-6 (HHV-6)
D. Parvovirus B19
E. Epstein-Barr Virus

Answer 201

►C

Exanthem Subitum (Roseola Infantum, Sixth Disease) is caused by human herpesvirus 6, and 7 (HHV-6, HHV-7).

Question 202

203- This is strain of HPV is associated with Butcher’s warts:

A. HPV-7
B. HPV 10, 13
C. HPV 30
D. HPV 2,4
E. HPV 28, 29

Answer 202

►A

The butcher warts are associated with HPV-7. Laryngeal carcinoma is associated with HPV-30. Common warts are HPV 2, 4.

Question 203

204- Which porphyrin is responsible for the fluorescence under Wood’s lamp examination of erythrasma?

A. Porphobilinogen
B. Protoporphyrin IX
C. Coproporphyrin III
D. Uroporphobilinogen
E. Coproporphyrinogen

Answer 203

►C

Erythrasma is caused by corynebacterium minutissimum. The presence of coprophyrinogen III created by the bacteria is responsible for the characteristic coral-red fluorescence under Wood’s lamp.

Question 204

205- Similar lesions were also seen on this infant’s face. Treatment of choice is:

A. phototherapy
B. oral steroids
C. acyclovir
D. topical retinoic acid
E. oral erythromycin

Answer 204

►C

This child has eczema herpeticum, a cutaneous infection with HSV which occurs in patients with pre-existing skin disorders such as atopic dermatitis. It begins as clusters of umbilicated and hemorrhagic vesicles in areas of abnormal skin. Lesions spread rapidly but can respond quickly to antiviral treatment. Children with underlying AD who come into frequent contact with an individual with orolabial HSV may have recurrent outbreaks of eczema herpeticum.

Question 205

206- Erythema infectiosum is caused by a:

A. RNA virus

B. Herpes virus
C. Double stranded DNA virus
D. Single stranded DNA virus
E. None of these answers are correct

Answer 205

►D

Erythema infectiosum is caused by parvovirus B19 which is a single stranded DNA virus.

Question 206

207- Blueberry Muffin Baby can be a feature of all of the following EXCEPT:

A. TORCH
B. Klippel-Trenaunay-Weber syndrome
C. Hemolytic disease of the newborn
D. Rhabdomyosarcoma
E. Langerhans‟ cell histiocytosis

Answer 206

►B

Blueberry muffin lesions can be seen in the setting of prenatal infections (e.g. TORCH), severe anemia (e.g. Hemolytic Disease of the newborn) and neoplastic diseases (e.g. rhabdomyosarcoma). It is not associated with the Klippel-Trenaunay-Weber syndrome.

Question 207

208- Which of the following is the causative organism of cat-scratch disease?

A. B. quintana
B. B. henselae
C. B. bacilliformis
D. B. duttonii
E. B. burgdorferi

Answer 207

►B

B. henselae is the cause of cat-scratch disease. Humans are infected by a cat bite or scratch, while the cat flea is responsible for cat to cat transmission.

Question 208

209- The most common location of herpes gladiatorum is the:

A. Groin
B. Chest
C. Anterior thigh
D. Face
E. Hand

Answer 208

►D
The face is the most common location for Herpes Gladiatorum.

Question 209

210- You are on a medical mission in the Peruvian Amazonia and are asked to examine a patient. The patient is concerned about a skin lesion on her abdomen. What is the most likely diagnosis in your differential?

A. Yellow fever
B. Dengue fever
C. Malaria
D. Strongyloidosis
E. Leptospirosis

Answer 209

►D

Strongyloides stercoralis has a very low prevalence in societies where fecal contamination of soil or water is rare. It is a very rare infection in developed economies and most common in tropical climates. Strongyloides stercoralis causes morphologically variable skin lesions. Rarely, a petechial purpuric eruption which resembles multiple thumbprints may initially present over the periumbilical area. Later on it may involve the whole abdomen, thighs, legs and arms. The petechial purpuric skin

lesions in disseminated strongyloidiasis are due to damage to the blood vessels caused by larval migration.

Question 210

211- Which of the following are potential forms of perinatally-acquired neonatal herpes disease?

A. Skin, eyes, mouth (SEM)
B. CNS
C. Disseminated
D. None of the above
E. All of the above

Answer 210

►E

Perinatally acquired neonatal herpes disease can present in three different, occasionally overlapping, forms: 1. skin, eyes, and mouth; 2. CNS; and 3. Disseminated, causing encephalitis, hepatitis, pneumonia, and coagulopathy.

Question 211

212- Measles is caused by a:

A. Paramyxovirus
B. Togavirus
C. Picornavirus
D. Rhabdovirus
E. Adenovirus

Answer 211

►A

The measles virus is an RNA virus belonging to the Paramyxovirus family.

Question 212

213- A patient presents with this anesthestic plaque. Which cytokines are upregulated in this disease?

A. IL-2
B. IL-4
C. IL-5
D. IL-10
E. All of these cytokines are upregulated

Answer 212

►A
Leprosy is caused by infections to Mycobacterium leprae. It is a acid fast bacilli. In tuberculoid leprosy, Th1 cytokines (IL-2, IFN-gamma) are upregulated. Clinically, patients have few, wellcircumscribed anesthetic plaques.

Question 213

214- The Mikulicz is the histologic hallmark of which of the following conditions:

A. Leishmaniasis
B. Granuloma inguinale
C. Rhinoscleroma
D. Rhinosporidiosis
E. Histoplasmosis

Answer 213

►C

Rhinoscleroma is caused by Klebsiella rhinoscleromatis, a gram negative rod that causes a chronic granulomatous infection of the upper respiratory tract. It is predominantly seen in Mexico, Central and South America. The histologic hallmark is the Mikulicz cell, a large histiocyte that contains the bacteria in its cytoplasm. Rhinosporidiosis is not an intracellular bacteria, but an extracellular fungi caused by Rhinosporidium seeberi mainly seen in India, Sri Lanka and occasionally the southeastern United States. Extremely large endospores are present in tissue. The other listed organisms are intracellular pathogens but do not have the Mikulicz cell as a feature of infection.

Question 214

215- A 24 year-old man from New York City develops fever, chills, malaise, and a severe headache. His apartment has a mouse problem. On examination, multiple, discrete papulovesicles and a single eschar are found. What is the most likely diagnosis?

A. Ehrlichiosis
B. Rickettsialpox
C. Q Fever
D. Meningococcemia
E. Rocky Mountain Spotted Fever

Answer 214

►B

The clinical description is that of rickettsialpox, which is caused by R. akari and spread by liponyssoides sanguineus - the house mouse mite.

Question 215

216- High doses of which of the following antiviral agents has been associated with thrombotic thrombocytopenic purpura in immunosuppressed patients?
A. Valcyclovir
B. Acyclovir
C. Foscarnet
D. Famciclovir
E. Cidofovir

Answer 215

►A

Thrombotic thrombocytopenic purpura has been reported with high doses of valcyclovir in immunosuppressed patients.

Question 216

217- A 42 year-old woman presents with a large, vegetating ulcer involving her left labia majora and groin for over 1 year. A Giemsa”s stained touch preparation reveals bipolar, safety pin-shaped intracytoplasmic inclusions. What is the most likely diagnosis?

A. Lymphogranuloma venereum
B. Granuloma Inguinale
C. Chancroid
D. Primary herpes simplex

E. Gonorrhea

Answer 216

►B

Bipolar, safety pin-shaped intracytoplasmic inclusions on Giemsa stain - known as Donovan bodies
- are diagnostic of granuloma inguinale.

Question 217

218- Sun exposure has been associated with the development of what type of warts?

A. Flat warts
B. Myrmecial warts
C. Common warts
D. Butcher’s warts
E. Condyloma accuminatum

Answer 217

►A

Warts are common cutaneous lesions caused by the various human papilloma virus subtypes. Flat warts are commonly caused by HPV subtypes 3, 10, 28, and 41. Sun exposure has been implicated as a potential factor in the formation of flat warts.

Question 218

219 -The culture medium that is used for Leishmaniasis is:

A. Novy-MacNeal-Nicolle
B. Giemsa
C. Sodium stibogluconate
D. FTA-ABS
E. ELISA

Answer 218

►A

Leishmaniasis should be cultured in Novy-MacNeal Nicolle (NNN) medium. Sodium stibogluconate is the treatment for cutaneous Leishmaniasis. FTA-ABS and ELISA are used to diagnose syphilis.

Question 219

220- Of the choices listed, which antiobiotic is the best to treat a 7-year old child with erythema migrans?

A. Doxycycline
B. Amoxicillin
C. Azithromycin
D. Tetracycline
E. Rifampin

Answer 219

►B

Doxycycline is the usual treatment for erythema migrans in adults in the absence of neurologic or cardiovascular complications. In children less than 8, all tetracyclines are relatively contraindicated because of they can cause tooth discoloration. Therefore amoxicillin should be used as the first line therapy for children less than 8. Note: Changes have been made to the treatment of RMSF. Children of any age should be treated with doxycycline for that disease.

Question 220

221- A patient with sparsely distributed hemorrhagic vesiculopustules with erythematous bases on palms, soles and over joint. The causative agent is Neisseria gonorrhoeae and the treatment is:

A. Ceftriaxone IV
B. Amphicillin
C. Rifampin
D. Penicillin
E. TMP-SMX

Answer 220

►A

Gonococcemia is caused by Neisseria gonorrhoeae. The clinical features are fevers, chills, arthralgias, malaise with hemorrhagic vesiculopustules with erythematous base on palms, soles and over joints.

Question 221

-A 24 year old male presents with a high fever, arthralgias, and a rash characterized by nonspecific erythematous macules in a generalized distribution. He was recently cleaning his family’s barn, and was bitten more than once by rats and mice. What is the treatment of choice for this infection?

A. Penicillin
B. Erythromycin
C. Clindamycin
D. Ciprofloxacin
E. Amikacin

Answer 221

►A

Rat-bite fever is also called Haverhill Fever. It is caused by Streptobacillus moniliformis and is acquired from infected rodents or by touching or eating contaminated food. The signs and symptoms are nonspecific, but the diagnosis can be suspected based on history. Treatment is with penicillin.

Question 222

223- A 10 year-old girl presents to the dermatology clinic with a pruritic eruption on her trunk after swimming at a beach in Florida. Of note, the lesions are limited to skin that was covered by her bathing suit. The most likely diagnosis is:

A. Seabather?s eruption
B. Swimmer?s itch
C. Cercarial dermatitis
D. Swimming pool granuloma
E. Cutaneous larva migrans

Answer 222

►A

Seabather?s eruption characteristically involves areas covered by swimwear, as a result of coelenterate larvae becoming trapped underneath bathing suits. The causative organisms are larval forms of Edwardsiella lineata (sea anemone) and Linuche unquiculata (thimble jellyfish).

Question 223

224- The mechanism of action of this virulence factor of Bacillus anthracis is via increasing the activity of tumor necrosis factor alpha:

A. Lethal toxin
B. Edema toxin
C. Polyglutamate acid capsule
D. All of the above answers are correct
E. None of the above answers are correct

Answer 223

►A

Bacillus anthracis is responsible for causing Anthrax. Anthrax of the skin is characterized by a painless edematous nodule which rapidly degenerates into an eschar. B. anthracis has 3 virulence factors: a polyglutamate acid capsule which inhibits phagocytosis of the bacteria, edema toxin (edema factor and protective factor) which results in edema secondary to induction of cAMP pathway, and lethal toxin (lethal factor and protective factor) which leads to shock and death via increasing TNFalpha activity.

Question 224

225- A 62 year-old man presents with tinnitus, facial paralysis, and vesicles of the external ear. What is the most likely diagnosis?

A. Primary Herpes Simplex infection
B. Primary Varicella Infection
C. Herpes Zoster Infection
D. Cytomegalovirus infection
E. Coxsackievirus A16 infection

Answer 224

►C

This patient has Ramsay Hunt Syndrome, herpes zoster infection of the geniculate ganglion. Vesicles can be seen on the tympanic membrane and the external ear. Symptoms include ipsilateral facial paralysis, tinnitus, or other auditory symptoms. Treatment is with acyclovir and systemic corticosteroids.

Question 225

Scrofuloderma is most commonly associated with an underlying infection of what organ system?

A. Lymph nodes
B. Spine
C. Lungs
D. Gastrointestinal tract
E. No underlying systemic disease

Answer 225

►A

Scrofuloderma is a tuberculous or nontuberculous mycobacterial infection affecting children and young adults, representing direct extension of tuberculosis into the skin from underlying structures such as lymph nodes, bone, or lung. It most commonly presents as a neck abscess secondary to a tuberculosis infection of the cervical lymph nodes. It is manifested by the development of painless subcutaneous swellings that evolve into cold abscesses, multiple ulcers, and draining sinus tracts.
The diagnosis is based on positive Mantoux test/PPD test, histologic
features of caseating granulomatous inflammation, culture, and favorable response to anti tuberculosis therapy.

Question 226

227- An 18-year old man presents to the Dermatology Clinic with a nontender penile erosion that has been present for 2 weeks. An indurated border and nontender bilateral inguinal lymphadenopathy are also noted. What is the most likely diagnosis?

A. Primary syphilis
B. Chancroid
C. Herpes simplex
D. Lymphogranuloma venereum

E. HIV

Answer 226

►A

A painless chancre with an indurated border is characteristic of primary syphilis. Associated painless lymphadenopathy (“buboes”) is also a common feature.

Question 227

228- A 40-year-old male patient from South America with HIV (CD4+ <200) presents with new purple-red papules and nodules on his face that have been progressively enlarging. A biopsy is performed, showing lobular vascular proliferations with plump endothelial cells on H&E staining. Immunohistochemical staining of skin tissue for human herpes virus 8 (HHV8) is negative. Upon closer inspection of H&E-stained sections, faint purple granular interstitial deposits are noted in the dermis. Which of the following tissue stains is most appropriate for further work-up?

A. Fite
B. Chloroacetate esterase
C. Warthin-Starry
D. Giemsa
E. Ziehl-Neelsen

Answer 227

►C

Causes of angiomatous papulonodules arising in immunocompromised patients include Kaposi‟s sarcoma, bacillary angiomatosis, and verruga peruana, as well as pyogenic granulomas and cherry angiomas. Bartonella, a gram negative bacillus, appears as faint purple-blue granular dermal deposits on routine H&E-stained sections. These deposits appear black upon WarthinStarry staining. Prominent endothelial cells may also be seen. Both B. henselae and B. quintana have been implicated in the pathogenesis of bacillary angiomatosus, while B. bacilliformis is the causative agent in verruga peruana (as well as Bartonellosis). Erythromycin is the first -line treatment for bacillary angiomatosus, while fluoroquinolones plus a tetracycline are the first-line agents for treatment of verruga peruana.

Question 228

229- Bacillary angiomatosis is caused by which of the following organisms?

A. B. quintana
B. B. henselae
C. B. bacilliformis
D. B. quintana and B. henselae
E. All of these answers are correct

Answer 228

►D
B. quintana or B. henselae are both causative organisms for bacillary angiomatosis.

Question 229

230- One of your colleagues returned from a vacation to India with fever, vomiting, pleural effusions, ascites and conjunctival petechiae. She also has a diffuse macular rash with notable areas of sparing that your attending refers to as “white islands in a sea of red”. What is your diagnosis?

A. Leishmania
B. Dengue hemorrhagic fever
C. Malaria
D. Typhoid
E. Leptospirosis

Answer 229

►B

Dengue fever is caused by an Arbovirus and transmitted by the mosquito, Aedes aegypti and may cause Dengue Shock Syndrome and Dengue Hemorrhagic Fever. The infection starts with sudden onset of high fever, backache, retroorbital pain, bone and joint pain, depression and malaise. The disease is also called “break-bone fever.” One to seven days after onset of fever, rash presents characteristically starting on the dorsum and hands and feet spreading to limbs and torso. The eruption may become confluent with small, round islands of sparing, the so called “white islands in a sea of red.” Treatment is generally supportive as no antivirals are effective.

Question 230

231- Acrodermatitis chronica atrophicans is typically caused by:

A. Borrelia burgdorferi
B. Borrelia burgdorferi senso stricto

C. Borrelia garinii
D. Borrelia afzelii
E. Unknown

Answer 230

►D

Acrodermatitis chronica atrophicans, also known as primary diffuse atrophy, is characterized by the appearance on the extremities of diffuse reddish or bluish red, paper-thin skin allowing the blood vessels to easily be seen beneath the skin. It is caused by Borrelia afzelii and is tick transmitted by Ixodes ricinus. It is seen almost exclusively in Europe.

Question 231

232- Patients that are diagnosed with purpura fulminans with hemorrhagic infarction of the skin are infected with:
A. Group A streptococcus
B. Staphylococcus aureus
C. Francisella tularensis
D. Bacillus anthracis
E. Streptomyces somaliensis

Answer 231

►A

Purpura fulminans is causes by group A streptococcal infection. Clinically there are hemorrhagic infarction of the skin caused by disseminated intravascular coagulation. One can see symmetric large ecchymotic areas with irregular (“geographic”) borders on extremities, ears and nose most commonly.

Question 232

233- A 67-year-old man presents with grouped painful vesicles on an erythematous base on his lateral sacrum. He denies any history of herpes simplex type I or II. He is angry with you for suggesting that he may have herpes. What could explain this presentation?

A. He actually has “shingles” and your diagnosis is incorrect
B. A significant number of people are asymptomatic for HSV infection
C. He is lying

D. He has the early stages of Alzheimer‟s disease
E. This presentation represents a primary infection with Epstein Barr Virus, (HHV4)

Answer 232

►B

A significant number of people are asymptomatic for HSV infection but are seropositive for anti HSV antibodies. Lumbosacral HSV occurs in about 10% of HSV infections and is more common in older age groups. In some cases, this may be the “first” presentation of HSV that the patient is aware of. Shingles would be a reasonable consideration for the differential diagnosis and a direct immunofluorescence scraping and viral culture would confirm that this typical presentation of
HSV actually is. It is possible that the patient is lying or that he has early Alzheimer‟s disease, but less likely. EBV does not present in this manner.

Question 233

234- An 18 year old male presents complaining of pruritus, erythema, and edema of the hands and feet. A serum study for parvovirus antibodies is negative. What is the next most common cause of this syndrome?

A. Epstein-Barr virus
B. Measles virus
C. Coxsackie virus
D. Cytomegalovirus
E. Human herpes virus 6

Answer 233

►A

Papular-purpuric gloves and socks syndrome is characterized by pruritus, erythema, and edema of the hands and feet, primarily in teenagers and young adults. Parvovirus B19 is classically associated with this eruption. While all of the viruses listed as answer choices have been associated with this syndrome; Epstein-Barr virus is the best answer choice.

Question 234

235- A middle-aged female presents with purplish pruritic plaques on her dorsal wrist and whitish plaques on her buccal mucosa. A diagnosis of lichen planus is made. Which type of lichen planus is most strongly associated with Hepatitis C virus infection?

A. Mucosal ulcerative lichen planus
B. Hypertrophic lichen planus
C. Lichen planus pemphigoides
D. Lichen planus of the nails
E. Vulvar lichen planus

Answer 234

►A

Lichen planus presents a wide variety of cutaneous morphologies that share common histologic findings of a lichenoid lymphocytic infiltrate, basal vacuolization, and dyskeratotic keratinocytes. The form of lichen planus most strongly associated with Hepatitis C virus infection is mucosal ulcerative lichen planus.

Question 235

236- Pediculus humanus var. corporis (human body louse) is the vector in which of the following diseases:

A. Endemic typhus (R. typhus)
B. Epidemic typhus (R. prowazekii)
C. Q fever (C. burnetii)
D. Rickettsialpox (R. akari)
E. Rocky Mountain Spotted Fever (R. rickettsii)

Answer 235

►B

The human body louse is the implicated Trench fever, epidemic typhus, and relapsing fever. Trench fever usually affects alcoholic men and is manifested by fevers. Treatment is with ceftriaxone, erythromycin, or doxycycline. Epidemic typhus is manifested by fevers, chills, malaise, and a pink macular eruption beginning in the axilla and trunk. Treatment is with tetracycline or chloramphenicol. Relapsing fever is manifested by paroxysmal fevers, headache, lymphocytoma, and erythematous/petechial macules on trunk/extremities. Treatment is with doxycycline.

Question 236

237- Which of the following are inconsistent with the diagnosis of staphylococcal scalded skin syndrome?

A. Epidermal changes are produced by exfoliative toxins of staphlococcus
B. Initial event is usually a localized staph infection
C. Swabs and cultures of fluid filled blisters overwhelmingly grow staph
D. Prognosis is good in children with low mortality when anitbiotics are administered early
E. Cell necrosis does not occur in staphylococcal scalded skin syndrome as it does in T.E.N

Answer 236

►C

Staphylococcal scalded skin syndrome: Lesions extend far beyond areas of actual staphylococcal infection, by action of the epidermolytic exotoxin elaborated by the staphylococcus in remote sites. Usually the staphylococci are present at a distant focus such as the parynx, nose ear, or conjuctiva. If cultures are taken they should be obtained fromthe mucous membranes because the skin erythema and desquamation is due to the distant effects of the exfoliative toxin, unlike the sitaution in bullous impetigo, where S. aureus is present in the lesions. Epidermal changes are produced by exfoliative toxins of Staphylococcus. Inital event is usually a localized Staph infection. Prognosis is good in children with low mortality when anitbiotics are administered earyl. Cell necrosis does not occur in SSS as it does in toxic epidermal necrolysis.

Question 237

238- Milker‟s nodule is caused by infection with which of the following viruses?

A. Human herpesvirus-6 (HHV-6)
B. Human herpesvirus-8 (HHV-8)
C. Paravaccinia virus
D. Vaccinia virus
E. Orf virus

Answer 237

►C

Milker‟s nodule is caused by paravaccinia virus, a poxvirus of the genus Parapoxvirus. It is transmitted to humans from infected cows.

Question 238

239 -In addition to Kaposi”s sarcoma, HHV-8 infection is also the causative agent in:

A. Pityriasis rosea
B. Angiosarcoma
C. Primary effusion lymphoma
D. Bacillary angiomatosis
E. Pyogenic granuloma

Answer 238

►C

Human herpes virus 8 is a double stranded DNA virus. It is thought to be pathogenic in Kaposi”s sarcoma, primary effusion lymphoma, and Castleman”s disease. Primary effusion lymphoma is a rare B-cell lymphoma seen predominantly in patients with AIDS.

Question 239

240 -WHO recommendations for the treatment of multibacillary leprosy include all of the following EXCEPT:

A. Dapsone
B. Clofazimine
C. Clarithromycin
D. Rifampin
E. All of these answers are recommended for the treatment of multibacillary leprosy.

Answer 239

►C

Clarithromycin is not part of the WHO recommendations for the treatment of multibacillary leprosy.

Question 240

241 -Granuloma Inguinale is caused by:

A. Chlamydia trachomatis types I, II & III
B. Hemophilis ducreyi
C. Klebsiella granulomatis

D. Treponema pertenue
E. Treponema pallidum

Answer 240

►C

Granuloma inguinale is caused by an infection of Klebsiella granulomatis. It is a granulomatous skin disease of the genitals caused by sexual transmission. It is a gram negative rod that is similar to the Enterobacteriaceae. It is a smll, raised papule or subcutaneous nodule that rapidly ulcerates, rarely with lymphadenopathy. It is not self healing and spreads by radial extension.
Hemophilis ducreyi is the cause of chancroid, Chlamydia trachomatis causes Lymphogranuloma Venereum, Treponema pertenue causes Yaws and T. pallidum is the cause of syphilis.

Question 241

242 -A patient is diagnosed with tularemia. The clinical features seen is the ulceroglandular form that looks like a chancre like ulcer with raised boarders and regional lymphadenopathy seen on t he finger or hand. The patient mostly likely came into contact with:

A. Rabbits
B. Horses
C. Cats
D. Dogs
E. Deer

Answer 241

►A

Tularemia is caused by Francisella tularensis. It is most likely caused by infected rabbits seen in hunters. There are other forms such as glandular, chancriform, oculoglandular, pulmonary, oropharyngeal and meningeal. The treatment is streptomycin.

Question 242

243 -What is the definition of disseminated herpes zoster?

A. Involvement of two or more defined dermatomes
B. Symmetric bilateral involvement
C. Involvement of one cranial and one spinal nerve.

D. More than 20 vesicles outside of the primarily affected dermatome
E. Involvement of the trunk and at least one extremity.

Answer 242

►D

The definition of dissemianted herpes zoster is at least 20 vesicles seen outside of the primarily affected dermatome. The other option choices are distractors.

Question 243

244 -Each of the following species may be involved in necrotizing fasciitis except:

A. Pseudomonas
B. Clostridium
C. Streptococcus
D. Mycobacterium
E. Bacteroides

Answer 243

►D

Necrotizing fasciitis is a rapidly advancing acute necrotizing infection that may follow trauma, surgery, or occur spontaneously. It is associated with systemic toxicity and high mortality rat e. Clinically, erythema, edema, and edema progresses to dusky cyanosis, blistering and necrosis. Many virulent bacteria have been culturesd including Pseudomonas, Bacteroides, streptococci, staphylococcus, enterococci, and clostridium. Both aerobic and anaerobic cultures should be taken. Mycobacterium is not associated with necrotizing fasciitis.

Question 244

245- The usual culture medium for Mycobacterium leprae is:

A. Chocolate agar in 10% CO2
B. Lowenstein-Jensen
C. It cannot be cultured
D. Sheep‟s blood agar
E. Agar supplemented with heme and nicotinamide

Answer 244

►C

M. leprae cannot be grown in media or cell culture. It has been grown in mice footpads and in armadillos. Humans are the only natural host. It is endemic in the tropics and found worldwide. The Lowenstein-Jensen medium is used to culture mycobacteria most commonly. Neisseria gonorrheae is grown on chocolate agar in 10% CO2. Agar supplemented with heme (x-factor) and nicotinamide (v-factor) is needed for Hemophilus influenzae cultures. Sheep‟s blood agar is useful for identifying hemolytic strains of streptococcus and staphylococcus.

Question 245

246- A patient presents with multiple asensate patches on the abdomen. A diagnosis of leprosy is made. Which of the following regimens is the WHO recommendation for treatment of paucibacillary leprosy?

A. Dapsone and rifampin
B. Dapsone and clofazimine
C. Clofazimine and rifampin
D. Minocycline and rifampin
E. Minocycline and clofazmine

Answer 245

►A
Paucibacillary leprosy is characterized by three or fewer anesthetic and anhidrotic lesions. This form of leprosy develops when the body mounts a Th1 cytokine profile leading to rare bacilli found in the lesions. The WHO recommends treatment of paucibacillary leprosy with dapsone 100 mg daily for 6 months and rifampin 600 mg monthly for 6 months.

Question 246

247- Hutchinson”s teeth are a feature of which stage of syphilis?

A. Early congenital
B. Late congenital
C. Primary
D. Secondary
E. Tertiary

Answer 246

►B

Hutchinson”s teeth (widely-spaced, peg-shaped upper incisors) are a seen in Late Congenital Syphilis (> 2 years of age).

Question 247

248- A patient with HIV/AIDS develops disseminated flesh-colored papules with central umbilication. A diagnosis of molluscum contagiosum is made. What is the CD4 cell count below which molluscum contagiosum lesions are first seen in HIV patients?

A. 100
B. 200
C. 400
D. 800
E. 1000

Answer 247

►A

HIV/AIDS patients are afflicted with a wide variety of opportunistic pathogens. The spectrum of infectious diseases can be used to predict a patient’s CD4 helper T cell count. Molluscum contagiosum is usually not seen until a patient’s CD4 count drops below 100.

Question 248

249- Swimmer’s itch caused by the flat worms of the family Schistosomatidae have clinical features of:
A. pruritic papules and vesicles on uncovered skin
B. pruritic erythematous papules on covered swim wear
C. Serpiginous urticarial plaques on buttocks
D. Thumbprint purpura on periumbilical skin
E. Widespread petechiae on trunk/proximal extremities

Answer 248

►A

Swimmers itch also known as Clam Digger’s itch is caused by the cercarial forms flatworms of the family Schistosomatidae. The mode of infection is penetration of skin while bathing in infested

fresh or salt water in Northern United States and Canada. The clinical characteristics are pruritic papules and papulovesicles on uncovered skin.

Question 249

250- What is the first line treatment of streptococcal toxic shock syndrome?

A. Penicillin
B. Ciprofloxacin
C. Clindamycin
D. Doxycycline
E. Vancomycin

Answer 249

►C
Clindamycin is considered 1st line treatment of streptococcal toxic shock syndrome, as it inhibits secretion of the exotoxin.

Question 250

251- A 12 month old boy has the sudden onset of a fever of 40 degrees Celsius. When the fever breaks spontaneously in three days, an erythematous, morbilliform rash arises on the trunk and spreads to the arms and legs. The rash is not itchy, and lasts 1-2 days. What is the most likely viral cause of this syndrome?

A. HHV-6
B. Measles virus
C. Rubella virus
D. Coxsackie virus
E. Cytomegalovirus

Answer 250

►A

Roseola infantum is also known as exanthem subitum or sixth disease. It is seen in infants ages 6-36 months, and is characterized by the signs and symptoms as described. The syndrome is caused by Human Herpes Virus 6.

Question 251

252- Xenopsylla cheopis transmits:

A. Epidemic typhus
B. Murine typhus
C. Rickettsia prowazekii
D. Scrub typhus
E. Rickettsia akari

Answer 251

►B

Xenopsylla cheopis along with Ctenocephalides felis are fleas that transmit R. typhi, the organism responsible for murine or endemic typhus. The body louse or Pediculus humanus corporis transmits Rickettsia prowasekii the organism responsible for epidemic typhus. Scrub typhus is caused by R. tsutsugamushi and is transmitted by chiggers or trombiculid mite larvae.

Question 252

253- A 25-year old man with a history of a healed genital ulcer develops a diffuse papulosquamous eruption resembling pityriasis rosea. What is the most likely time lapse between the appearance of the genital lesion and the appearance of this eruption?

A. 3-12 weeks
B. 1-2 weeks
C. 3-5 months
D. 6-12 months
E. 1-2 years

Answer 252

►A

The lesions of secondary syphilis are often diffusely distributed due to spirochetemia. Papulosquamous lesions are characteristic, and the presence of constitutional symptoms such as fever, fatigue, headaches, and bone pain may help distinguish secondary syphilis from pityriasis rosea. Other lesions of secondary syphilis include ˜moth-eaten” alopecia, mucous patches, split papules, and condyloma lata. The mucocutaneous manifestations of secondary syphilis typically occur 3-12 weeks after the appearance of the chancre and last 4-12 weeks.

Question 253

254- Through which cellular protein does molluscum contagiosum evade host immunity?

A. IL-18 binding protein
B. Beta-4 integrin
C. T cell receptor
D. MHC II
E. Toll-like receptor 7

Answer 253

►A

Molluscum contagiosum virus, like other viral and bacterial pathogens, attempts to exploit the host immune system to avoid destruction. In this case, molluscum contagiosum virus usesIL-18 binding protein, which blocks the host helper T (Th1) response by reducing local IFN-gamma production.

Question 254

255- Which of the following is the vector responsible for the transmission of Verruga Peruana?

A. Lutzomyia verrucarum
B. Tsetse fly
C. Ctenocephalides felis
D. Pediculus humanus corporis
E. Simulium slossonae

Answer 254

►A

Verruga Peruana is caused by infection with B. bacilliformis, which is transmitted by the sandfly, Lutzomyia verrucarum.

Question 255

256- The causative organism of epidemic typhus is:

A. Francisella tularensis
B. R. prowazekii
C. R. akari
D. R. typhi

E. Salmonella typhi

Answer 255

►B

Epidemic typhus is caused by infection with R. prowazekii.

Question 256

257- Dracunculiasis is typically acquired from:

A. Soil
B. Salt water
C. Drinking water
D. Chiggers
E. Black flies

Answer 256

►C

Dracunculiasis, which is caused by Dracunculus medinensis, is acquired by ingestion of copepod- infested water.

Question 257

258- A young patient presents to you after participating in a bar brawl a few nights before with a painful swollen erythematous right hand. The most likely organism is:

A. Staphylococus aureus
B. Eikenella corrodens
C. Pasturella multocida
D. Streptococcus pyogenes
E. Bacteriodes fragilis

Answer 257

►B

Eikenella corrodens is a member of normal oral flora, that is commonly the cause of human bite and fist fight infections. Pasturella multocida is a common organism found in dog and cat bites. Staph

and Strep could be the right answers for a cellulitis, but with this history are not the correct choices. Baceriodes fragilis is found in normal bowel flora.

Question 258

259- Which of the following manifestations of syphilis would you expect to be present 2-6 months after the individual was exposed?

A. Osteitis
B. Aortitis
C. Tabes dorsalis
D. Condylomata lata
E. Pseudochancre redux

Answer 258

►D

All of the listed options except condylomata lata are manifestations of tertiary syphilis, which does not manifest for years after the initial infection. Secondary syphilis presents 2 -6 months following infection. Condylomata lata are moist, flat and smooth. Do not confuse them with Condyloma accuminatum which are usually dry, cauliflower-like projections on the genitalia.

Question 259

260- Which of the following forms of syphilis is characterized by ham-colored macules on the palms and soles, condyloma lata, and “moth-eaten” alopecia?

A. Primary
B. Secondary
C. Latent
D. Tertiary
E. Congenital

Answer 259

►B

Secondary syphilis is characterized by ham-colored macules on the palms and soles, condyloma lata, and “moth-eaten” alopecia, in addition to mucous patches and split papules. It typically lasts 4-12 weeks.

Question 260

261- The treatment of choice for acyclovir-resistant herpes simplex virus infection is:

A. Valcyclovir
B. Famciclovir
C. Indinivir
D. Saquinivir
E. Foscarnet

Answer 260

►E

Foscarnet directly inhibits viral DNA polymerase (without requiring phosphorylation by TK) and is therefore effective in acyclovir-resistant HSV infections. Cidofovir can also be used.

Question 261

262- What is the characteristic body on histopathology for this disease?

A. Cowdry Type A
B. Cowdry Type B
C. Henderson-Patterson
D. Guarnieri
E. Dutcher

Answer 261

►A

Herpes simlex virus is characterized by Cowdry type A bodies on histopathology. They appear as sharply demarcated eosinophilic structures separated by a clear halo from a basophilic rim of the infected cell’s marginated nuclear chromatin. Cowdry B bodies may be seen in polio infections.

Question 262

263- A 10-year-old boy develops an acute illness and rash along with marked enlargement of the posterior cervical lymph nodes. This presentation is most consistent with:

A. West African sleeping sickness
B. East African sleeping sickness

C. Chagas disease
D. Schistosomiasis
E. Sparaganosis

Answer 262

►A

West African sleeping sickness is caused by Trypanosoma bruci gambiense and leads to acute illness with rapid fatal course and pronounced posterior cervical lymphadenopathy (Winterbottom’s sign). East African sleeping sickness is due to T. brucei rhodesiense (east like rhode island) and is more chronic . American trypanosomiasis, or Chagas disease, features unilateral conjunctivitis and edema of the face (Romana’s sign) and heart and gastrointestinal sequelae. Schistomsomiasis causes swimmer’s itch, while sparaganosis from ingestion of Spirometra leads to painful edematous lumps.

Question 263

264- A patient develops gastroenteritis after a trip to the seacoast. He reports eating raw oysters at his favorite seafood restaurant. Which of the following organisms is the most likely cause of his gastrointestinal problems?

A. Vibrio vulnificus
B. Vibrio parahemolyticus
C. Mycobacterium marinum
D. Erysipelothrix rhusiopathiae
E. Treponema carateum

Answer 263

►B

Vibrio parahemolyticus is a cause of gastroenteritis after consuming contaminated seafood or shellfish. V. vulnificus infection occurs in cuts/wounds that contact contaminated seawater or marine organisms. M. marinum occurs after injury in an aquatic environment such as a fish tank or swimming pool. Lesions typically occur on hands, elbows or knees and are characterized by painless inflammatory nodules that may ulcerate and may occur in a sporotrichoid pattern. E. rhusiopathiae infection occurs after injuries in fishermen, butchers or those handling raw meat. Initially there is burning pain at the inoculation site followed by a gradually enlarging purple plaque with well defined margins. T. carateum is the cause of Pinta.

Question 264

A patient with a chronic nose-bleed is treated with nasal packing. The packing is accidentally left in place, and he develops Toxic Shock Syndrome. What is the implicated toxin?

A. Enterotoxin B
B. Toxic Shock Syndrome toxin 1
C. Exfoliative Toxin A
D. Edema toxin
E. Lethal factor

Answer 264

►A

Toxic Shock Syndrome is characterized by fever, hypotension, and a generalized scarlatiniform eruption followed by desquamation. Menstrual-associated TSS is generally driven by Staphylococcus aureus, which released Toxic Shock Syndrome toxin 1. In nonmenstrual cases, however, Enterotoxins B>C are more commonly implicated, although TSST-1 has also been associated. Exfoliative toxins A and B are involved in bullous impetigo, and edema toxin and lethal factor are involved in Bacillus anthracis infections.

Question 265

266- What rare hematologic disorder can accompany varicella-zoster virus infection?

A. Thrombocytopenia
B. Neutropenia
C. Lymphopenia
D. Lymphocytosis
E. Anemia

Answer 265

►A

Symptomatic thrombocytopenia, while rare, has been associated with acute varicella-zoster virus infection.

Question 266

267- Which anatomic locations are most commonly involved in herpes gladiatorum?

A. Lateral neck, lateral face, forearm
B. Tips of fingers
C. Feet
D. Upper thighs and buttocks
E. Scalp

Answer 266

►A

Herpes gladiatorum is most commonly seen on the lateral neck, lateral face, and forearm, areas which most commonly contact a competing wrestler or the wrestling mat.

Question 267

268- Post herpetic neuralgia can be prevented with the VZV vaccine. It is a Oka/Merck strain of VZV and is FDA approved for adults:

A. 60 and older
B. 50 and older
C. 55 and older
D. 65 and older
E. 70 and older

Answer 267

►A

Herpes zoster vaccine is a live attenuated vaccine and can help reduce the incidence of herpes zoster and decrease the chance of post-herpetic neuralgia.

Question 268

269- A 35 year-old woman who works in the animal product industry presents with a painless hemorrhagic bulla. A diagnosis of anthrax is suspected. Gram stain of the vesicle fluid should reveal which of the following?

A. Guarnieri bodies
B. Gram-negative cocci
C. Gram-negative bacilli

D. Gram-positive cocci
E. Gram-positive bacilli

Answer 268

►E

Anthrax is caused by Bacillus anthracis, which is a gram-positive spore-forming rod.

Question 269

270- What is the most important predictor of materal-fetal transmission of HSV-2?

A. Use of pre-natal antiviral medications
B. Length of delivery
C. Nature of maternal infection
D. Nutrition status of the mother
E. Use of peri-natal monitoring equipment.

Answer 269

►C

The nature of the maternal infection (primary versus recurrent) is the most important predictor of maternal-fetal transmission of HSV-2. In mothers with a primary infection, the risk of transmission is 25-50%. In mothers experiencing a recurrent infection, the risk is 2-5%

Question 270

271 -Contagious pustular dermatitis (Orf) is caused by a:

A. Herpesvirus
B. Poxvirus
C. Gram-positive spore-forming rod
D. Paramyxovirus
E. Papovavirus

Answer 270

►B

Orf is caused by orf virus (OV), a poxvirus of the genus Parapoxvirus.

Question 271

272- The treatment of choice of cat-scratch disease is:

A. Azithromycin
B. Ceftriaxone
C. Trimethoprim-sulfamethoxazole
D. Itraconazole
E. Mebendazole

Answer 271

►A

Cat-scratch disease is caused by Bartonella henselae, which is spread among cats by fleas. The hallmark of the disease is unilateral and regional lymphadenopathy. The treatment of choice for cat- scratch disease is Azithromycin.

Question 272

273- The most likely target for exfoliative toxin A in bullous impetigo is:

A. Desmocollin
B. BPAG1
C. BPAG2
D. Desmoglein 1
E. Desmoglein 3

Answer 272

►D

Bullous impetigo is caused primarily by staphylococcus aureus phage type 71. This bacteria produces exfoliative toxin A binds to desmoglein 1 and produces produces the blisters characteristic of bullous impetigo.

Question 273

274- Which Rickettsial infection has a negative Weil-Felix test?

A. Rocky Mountain Spotted Fever (R. rickettsii)
B. Mediterranean fever (R. conorii)
C. Epidemic typhus (R. prowazekii)

D. Endemic typhus (R. typhi)
E. Rickettsialpox (R. akari)

Answer 273

►E

Rickettsia are short, gram-negative rods which are strict intracellular parasites. The bacteria is transmitted via tick which much be attached for more than 6 hours. The Weil-Felix test exploits cross-reactivity between the Proteus vulgaris antigen and RIckettsia.

Question 274

275- Most common causative organism of the attached picture is

A. Corynebacterium minutissimum
B. Corynebacterium tenuis
C. Micrococcus sedentarius
D. Staphylococcus
E. Streptococcus

Answer 274

►C

The image shows Pitted keratolysis. It is a non-inflammatory bacterial infection caused by microcolonies of Micrococcus sedentarius or Corynebacterium species that produce a specific proteolytic enzyme which digests the stratum corneum. It consists of small crater-like depressions in the stratum corneum, and usually appear on the weight-bearing regions of the soles of the feet, but can occur in other non weight-bearing areas as shown in image. This was confirmed with shave biopsy of epidermis that is step-sectioned and stained with methenamine silver as this is found to be more helpful than a punch biopsy. The disease usually goes unnoticed by patients and is most often an incidental finding. Hyperhidrosis and malodor of the skin are very common findings. Corynebacterium minutissimum is the causative agent for erythrasma, and Corynebacterium tenius causes trichomycosis Axillaris.

Question 275

276- All of the following are features of scarlet fever except:

A. Pharyngitis

B. Pastia‟s lines
C. S. aureus infection
D. Circumoral pallor
E. Sandpaper-like texture

Answer 275

►C

Scarlet fever is primarily a disease of children with most cases occurring between the ages of 1 and 10 years of age. Streptococcus pyogenes is the causative organism. It produces the
streptococcus pyrogenic exotoxin which elicits the cutaneous manifestations by enhancing delayed type hypersensitivity to streptococcal products. Clinical findings include fever, sore throat, headache, chills, sandpaper rash on the trunks, strawberry tongue, and Pastia‟s lines (linear petechial streaks found in flexural locations).

Question 276

277- What is the most common cause of erythema multiforme?

A. Herpes simplex virus
B. Mycoplasma pneumonia
C. Amoxicillin
D. Ibuprofen
E. Cytomegalovirus

Answer 276

►A

The most common cause of erythema multiforme (EM) is herpes simplex virus, which may not be active at the time of the EM eruption. Patients with recurrent EM are typically treated with acyclovir or valacyclovir. Mycoplasma pneumonia is a cause of EM, but is not the most common. Amoxicillin, ibuprofen, and cytomegalovirus may cause EM, but are not as common.

Question 277

278- The patient in this photograph has claw hands, hypoesthesia of the distal extremities, madarosis and leonine facies. What type of leprosy does she have?

A. Lepromatous leprosy
B. Tuberculoid leprosy
C. Borderline leprosy
D. Erythema nodosum leprosum
E. Lucio phenomenon

Answer 277

►A

Hansen’s disease (aka Leprosy) is a chronic granulomatous disease principally affecting the skin and peripheral nervous system, caused by Mycobacterium leprae. Lepromatous leprosy is described where there is low immune response to the bacteria. The areas most commonly affected are the superficial peripheral nerves, skin, mucous membranes of the upper respiratory tract, anterior chamber of the eyes, and testes. These areas tend to be cool parts of the body. Tissue damage depends on the degree to which cell-mediated immunity is expressed, the type and extent of bacillary spread and multiplication, the appearance of tissue-damaging immunologic complications (ie, lepra reactions), and the development of nerve damage and its sequelae. The late complications of lepromatous leprosy include madarosis = loss of eyebrows, leonine facies, stockin gglove neuropathy and lagopthalmosis.

Question 278

279- This is the term that is used from tuberculosis of the skin and is spread by hematogenous, lymphatic, or contiguous spread. The clinical characteristic is brownish red plaque, apple jelly color on diascopy.

A. Lupus vulgaris
B. Scrofuloderma
C. Tuberculous Gumma
D. Tuberculosis verrucosa cutis
E. Tuberculosis cutis orificialis

Answer 278

►A

Lupus vulgaris spreads from hematogenous, lymphatic, or contiguous spread from distant site of tuberculous infection. It is sensitizes the host with moderate to high immunity. It is pauci bacillarry. It also involved the head/neck in 90% of cases.

Question 279

280- Which of the following diseases is caused by a virus?

A. Rocky Mountain spotted fever
B. Human monicytic ehrlichiosis
C. Colorado tick fever
D. Boutonneuse spotted fever
E. Q fever

Answer 279

►C

Rocky Mountain spotted fever is caused by Rickettsia rickettsii. Human monicytic ehrlichiosis is caused by Ehrlichia chaffeensis. Colorado tick fever is caused by Reoviiridae. Boutonneuse fever is caused by Rickettsia conorii. Q fever is caused by Coxiella burnetti.

Question 280

281- Which of the following statements best describes the pathogenesis of scrofuloderma?

A. Hematogenous spread of M. tuberculosis from a distant site of infection
B. Autoinoculation of M. tuberculosis from advanced pulmonary tuberculosis
C. Contiguous spread from an underlying focus of tuberculous lymphadenitis
D. Primary incoculation of M. tuberculosis in a sensitized host
E. An cutaneous manifestation of military tuberculosis

Answer 280

►C

Scrofuloderma is the result of contiguous spread onto skin from an underlying focus of tuberculous infection. This typically occurs in a sensitized host with low immunity.

Question 281

282- Which of the following tests is a specific test for infection with Treponema pallidum?

A. RPR
B. VDRL
C. FTA-ABS
D. CBC
E. Darkfield microscopy

Answer 281

►C

The FTA-ABS test measures the presence of antibodies in the patient‟s serum to the syphilis antigens, either on spirochetes or on attached red blood cells. The RPR and VDRL are non specific tests that rely on cross-reactive anti-phospholipid antibodies. Darkfield microscopy is not specific to
T. pallidum, but will identify other spirochetes also. A CBC would not be specific for T. pallidum.

Question 282

283- What percentage of patients undergoing stem cell transplantation for leukemia will develop herpes zoster within the first year?

A. 5%
B. 30%
C. 50%
D. 70%
E. 90%

Answer 282

►D

The risk of developing herpes zoster following stem cell transplantation for leukemia is quite high, approaching 70% in some studies.

Question 283

284- Herpes simplex virus infection and this condition has been linked to which HLA type?

A. HLA Cw6
B. HLA B15

C. HLA B27
D. HLA B51
E. HLA DR3

Answer 283

►B

HSV related erythema multiforme has been associated with an increased frequency of HLA-B15.

Question 284

285 -Heck‟s disease is associated with which of the following types of human papillomavirus?

A. 1
B. 3
C. 7
D. 6/11
E. 13/32

Answer 284

►E

Heck‟s disease (focal epithelial hyperplasia) is caused by HPV 13 and 32 infections. These lesions are multiple circumscribed papules on the oral mucosa that may resemble oral condyloma. They are not pre-cancerous. HPV-1 is associated with plantar warts, while HPV-3 is associated with flat warts. HPV-7 cause “butcher‟s warts” and are believed to be acquired from handling meat, poultry and fish.

Question 285

286- What is the first-line recommended therapy for orf?

A. Penicillin
B. Erythromycin
C. Doxycycline
D. Bactrim
E. No therapy is needed since the condition is self-resolving

Answer 285

►E

No therapy is needed, since orf is usually a benign, self-resolving infection. Orf is caused by a parapoxvirus, often associated with sheep and goats. The infection undergoes 6 different stages of evolution: the papular, target, acute, regenerative, papillomatous, and regressive stages.

Question 286

287- A patient with hypertophic plaques on the external nares with Mikulicz cells seen on histopathology is infected with:
A. Klebsiella pneumoniae rhinoscleromatis
B. Streptobacillus moniformis
C. Erysipelothrix rhusiopathiae
D. Bukholderia mallei
E. Pseudomonas aeruginosa

Answer 286

►A

This patient has rhinoscleroma, which looks like hypertrophic plaques on external nares. The causative organism is Klebsiella pneumoniae rhinoscleromatis. Mikulicz cells are seen on histopathology and the treatment is ciprofloxacin.

Question 287

288- This is the cause of bacillary angiomatosis:

A. B. burgdorferi
B. B. henselae and B. quintana
C. B. bacilliformis
D. B. dammini
E. B. pacificus

Answer 287

►B

Bacillary angiomatosis is caused by both B. henselae and B. quintana. The vector is unknown and the treatment is erythromycin and doxycycline.

Question 288

289- The usual culture medium for mycobacteria is:

A. Chocolate agar in 10% CO2
B. Lowenstein-Jensen
C. New York City
D. Sheep”s blood agar
E. Agar supplemented with heme and nicotinamide

Answer 288

►B

The Lowenstein-Jensen medium is used to culture mycobacteria most commonly. Neisseria gonorrheae is be grown on chocolate agar in 10% CO2. Thayer “Martin, Martin-Lewis or New York City medium also allow for N. gonorrheae growth. Agar supplemented with heme (x factor) and nicotinamide (v-factor) is needed for Hemophilus influenzae cultures. Sheep”s blood agar is useful for identifying hemolytic strains of streptococcus and staphylococcus.

Question 289

290- Herpangina is caused by which of the following?

A. Group A coxsackievirus
B. Epstein Barr Virus
C. Parvovirus B19
D. Human Herpesvirus 6 (HHV-6)
E. Human Herpesvirus 6 (HHV-7)

Answer 289

►A

Herpangina is caused by Group A coxsackievirus.

Question 290

291 -What is the most common site of infection from Streptococcus Iniae?

A. Lower leg
B. Face
C. Hand
D. Foot
E. Nails

Answer 290

►C

Streptococcus iniae most commonly causes bacteremic cellulitis of the hand in persons who have recently handled fresh fish. S. iniae is a fish pathogen that causes sporadic infection in tilapia, yellowtail, rainbow trout, and coho salmon. Treatment of choice is with penicillin antibiotics.

Question 291

292- An HIV infected male, presents with a two-week history of a painless 2 cm ulcer on the penile shaft, with associated inguinal lymphadenopathy. What is the best treatment?

A. Valacyclovir
B. Benzathine penicillin G
C. Ceftriaxone
D. Doxycycline
E. Azithromycin

Answer 291

►B

A painless ulcer in an HIV patient is most likely a syphilitic chancre. The treatment of choice is benzathine penicillin G in patients without a penicillin allergy. Alternative agents in allergic patients include doxycycline, tetracycline, erythromycin, and ceftriaxone. Valacyclovir would be the treatment of choice for genital herpes, which is typically painful. Azithromycin in a single 1 g oral dose is effective for chancroid, which is painful.

Question 292

293- All of the following statements are true of Bacillus anthracis infection except:

A. Spores remain stable for decades
B. 20% mortality rate in untreated cutaneous infections
C. Inhalation, GI and cutaneous forms exist
D. Ciprofloxacin and doxycycline are first line treatments
E. All statements are true

Answer 292

►E

Anthrax can present in three different clinical forms: cutaneous, inhalational, and gastrointestinal.
The cutaneous form appears as a painless vesicle that later forms an eschar
(malignant pustule). The cutaneous form has a mortality rate of less than 1% if treated an up to 20% if untreated.

Question 293

294- This animal is a nonhuman source of infections for patients for Mycobacterium leprae:

A. Armadillos
B. Horses
C. Tic
D. Fleas
E. Pigs

Answer 293

►A

Leprosy is caused by mycobacterium leprae. Armadillos are a source of nonhuman source for leprosy. They are also transmitted from human to human most likely from respiratory secretions.

Question 294

295- These are all old world Leishmaniasis except for:

A. L. mexicana
B. L. major
C. L. tropica
D. L. aethiopica
E. L. infantum

Answer 294

►A

The organisms that are responsible for old world Leishmaniasis are L. major, L. tropica, L. aethiopica, L. infantum, L. donovani. Those that are responsible for new world Leishmaniasis are in south and central America which are L. mexicana, L. braziliensis, and L. amazonensis.

Question 295

296- Which subtype of the human papilloma virus is most likely to have caused this infection?

A. HPV, type 1
B. HPV, type 2
C. HPV, type 3
D. HPV, type 5
E. HPV, type 6

Answer 295

►E

The human papilloma virus is a member of the Papovavirus family, a double-stranded DNA virus. HPV, type 6 has been implicated in giant conduloma of Buschke and Lowenstein and anogenital condyloma.

Question 296

297- Streptococcus Iniae has been shown to cause:

A. Perianal dermatitis in neonates
B. Necrotizing fasciitis
C. Bullous impetigo
D. Hand cellulitis in fish handlers
E. Perineal erysipelas in postpartum women

Answer 296

►D

Streptococcus iniae has been demonstrated to cause hand cellulitis from puncture wounds sustained form the dorsal fin, fish bone or knife of usually a tilapia. Treatment with PCN is curative. Group A Streptococci are the most common cause of perianal dermatitis. Many different bacteria have been implicated in necrotizing fasciitis. Bullous impetigo is most frequently caused by phage type 71 S. aureus or a related group 2 phage type. Group B streptococcus is most often responsible for perineal erysipelas in postpartum women.

Question 297

298- Which of the following organisms is spread by non-sexual person-to-person contact?

A. Treponema carateum
B. Chlamydia trachomatis types I, II & III
C. Hemophilis ducreyi
D. Calymmatobacterium granulomatis
E. Treponema pallidum

Answer 297

►A

Treponema carateum is the cause of Pinta which is primarily transmitted by direct contact. Occasional insect vectors have also been implicated, but sexual contact is not the primary cause of spread. The other options (C. trachomatis, H. ducreyi, C. granulomatis and T. pallidum) are all venereal diseases.

Question 298

299- A patient has a painless, soft erosion that heals spontaneously. The p atient also has secondary inguinal adenopathy with fluctuant, tender nodes above and below Poupart’s ligament. This patient most likely has:

A. Lymphogranuloma venereum
B. Granuloma inguinale
C. Chancroid
D. Chancre
E. Tertiary syphillis

Answer 298

►A

The patient has lymphogranuloma venereum that is caused by Chlamydia trachomatis L1, L2, L3. It is a painless soft erosion that heals spontaneously. Serologic diagnosis is by complement fixation test. The treatment is doxycycline.

Question 299

300- A 52-year old male develops a brownish-red plaque on his forehead. The lesion has an “apple jelly” color on diascopy, and the patient has a positive PPD skin test. What is the most likely mechanism of disease in this patient?

A. Spread from a distant site
B. Exogenous re-infection
C. Primary inoculation
D. Contiguous spread to skin from underlying infection
E. Id reaction

Answer 299

►A

This patient has lupus vulgaris, a pauci-bacillary manifestation of tuberculosis infection. Lesions occur in sensitized patients with a moderate to high immune response and are due to hematogenous, lymphatic, or contiguous spread from a distant site of infection. Lesions typically occur on the head and neck. “Apple jelly” color on diascopy is described in lupus vulgaris, but can also be seen in cutaneous lesions of sarcoidosis.

Question 300

301- A patient has palpable purpura, arthralgias and glomerulonephritis and is diagnosed with cryoglobulinemia. The most common infection associated with this is:

A. Hep C
B. Hep A
C. Hep B
D. Epstein Barr Virus
E. CMV

Answer 300

►A

This patient has cryoglobulinemia. This is associated with HCV infection. Approximately 80% of cases of mixed cryoglobulinemia are associated with HCV infection.

Question 301

302- A patient presents with painful vesicles in a dermatomal distribution on his forehead and on the tip of his nose. He is sent by his ophthalmologist who diagnosed ophthalmic zoster. Which nerve branch is involved?

A. Ophthalmic

B. Nasal
C. Infraorbital
D. Supraorbital
E. Temporal

Answer 301

►A

The ophthalmic branch of the trigeminal branch is involved in ophthalmic zoster. This presentation accounts for 10-15% of all cases of VZV. The other nerve branches listed are not involved in ophthalmic zoster.

Question 302

303- Coxsackievirus A16 is implicated in the pathogenesis of which of the following dieases?

A. Exanthem subitum
B. Fifth disease
C. Papular purpuric “gloves and socks” syndrome
D. Erythema infectiousum
E. Hand-Foot-and-Mouth disease

Answer 302

►E

Hand-Foot-and-Mouth disease is caused by coxsackievirus A16. Group A coxsackievirus infection is also associated with herpangina.

Question 303

304- A patient is diagnosed with hepatitis C. The most common associated autoimmune disorder associated with hepatitis C is:

A. autoimmune thyroiditis
B. aplastic anemia
C. autoimmune thrombocytopenic purpura
D. Peripheral neuropathy
E. Arthralgias

Answer 303

►A

The most common associated autoimmune disorder is autoimmune thyroiditis. The others can be associated with hepatitis C extra systemic manifestation but is not as common.

Question 304

305- A middle aged man of southern-eastern european heritage has red to blue-black patches on the feet. The most likely cause of this disease is:

A. HHV-8
B. HHV-7
C. HHV-6
D. HHV-5
E. HHV-4

Answer 304

►A

This patient above has classic kaposi’s sarcoma. It is caused by HHV-8 that causes the abnormal vascular proliferation associated with this condition. Classic KS is seen in middle aged men from southern-eastern european heritage.

Question 305

306- Which of the following is a gram positive rod?

A. Meningococcemia
B. Gonorrhea
C. Glanders
D. Melioidosis
E. Anthrax

Answer 305

►E

Anthrax is a gram positive, spore-forming rod. Meningococcemia, gonorrhea, Glanders, and Meloioidosis are all gram negative. Infection with anthrax initially begins after skin onoculation or may follow after ingestion or inhalation of spores. Cutaneous anthrax initially begins as a localized

infection and subsequently evolves to toxemia. It appears as a painless papule that ay later become hemorrhagic or nerotic. It produces two exotoxins: edema toxin and lethal toxin. Edema toxin is comprised of edema factor and protective antigen. Lethal toxin is composed of lethal factor and protective antigen.

Question 306

307- The vector of Trench Fever is the:

A. Human body louse (Pediculus humanus corporis)
B. Cat flea (Ctenocephalides felis)
C. Sandfly (Phlebotamus perniciosus)
D. Rat flea (Xenopsylla cheopis)
E. Trombiculid mite

Answer 306

►A

The human body louse (Pediculus humanus corporis)is the vector of Trench Fever, Epidemic Typhus, and Relapsing Fever.

Question 307

308 -The causative organism for Brucellosis is which of the following:

A. Gram positive rod
B. Gram positive cocci
C. Gram negative rod
D. Gram negative cocci
E. Acid fast bacilli

Answer 307

►C

Brucella species which cause Brucellosis are gram negative rods. Brucellosis, aka undulant fever, is characterized by an acute febrile illness with headache and joint pain. CNS and cardiac manifestations can also occur. It is acquired by contact with infected animals or contaminated dairy products. Treatment is with doxycycline and rifampin.

Question 308

309- What is the treatment for secondary syphillis in a penacillin allergic patient?

A. Penicillin
B. Doxcycyline
C. Rifampiin
D. Clindamycin
E. Ceftriaxone

Answer 308

►B

Secondary syphillis is caused by the spirochete, T. pallidum. Penicillin is the treatment of choice for secondary syphillis. In penicillin allergic individuals, doxycyline may be used. Treatment for neurosyphilis, congenital syphilis and syphilis in pregnant women is desensitization to penicillin and then treatment with pcn.

Question 309

310- A 27 year-old man with a 1-month history of bilateral inguinal lymphadenopathy and a positive “groove sign”. What is the most likely diagnosis?

A. Syphilis
B. Herpes simplex
C. Chancroid
D. Lymphogranuloma venereum
E. Gonorrhea

Answer 309

►D

Inguinal adenopathy with fluctuant, tender nodes above and below Poupart”s ligament - referred to as “groove sign” - is a characteristic clinical feature of lymphogranuloma venereum.

Question 310

311- A 45 year old septic female develops symmetric, large ecchymotic areas with irregular borders on the extremities, ears, and nose. Laboratory testing reveals the patient has disseminated intravascular coagulation. Which of the following is the most common underlying infection associated with this condition?

A. Group A streptococcus
B. Meningococcus
C. Staphylococcus
D. Pseudomonas
E. Mycobacterium

Answer 310

►B

Purpura fulminans is an oftentimes dramatic presentation of large ecchymotic areas of the skin, favoring acral sites including the extremities, ears, and nose. The underlying pathophysiology is hemorrhagic infarction of the skin due to disseminated intravascular coagulation. Meningococcal infection is the leading underlying infection associated with sepsis and purpura fulminans. When Kids develop purpura fulminans after an infection the most common cause is group A Strep.

Question 311

312- What characteristic color is seen on diascopy of this lesion?

A. Apple jelly
B. Blue
C. Orange
D. Red
E. Coral red

Answer 311

►A

Leishmaniasis recidivans is a type of Old World leishmaniasis. Clinically, it appears as a red papule covered with white scale. On diascopy, it has a characteristic apple jelly color.

Question 312

313- Neisseria gonorrheae would be identified with:

A. Sheep”s blood agar
B. Agar supplemented with heme and nicotinamide
C. Chocolate agar with 10% CO2
D. Chocolate agar

E. Darkfield microscopy

Answer 312

►C

Neisseria gonorrheae should be grown on chocolate agar in 10% CO2. Thayer”Martin, Martin- Lewis or New York City medium also allow for N. gonorrheae growth. Agar supplemented with heme (x-factor) and nicotinamide (v-factor) is needed for Hemophilus influenzae cultures.
Darkfield microscopy is helpful in diagnosing infections with Treponema pallidum (syphilis). Sheep”s blood agar is useful for identifying hemolytic strains of streptococcus and staphylococcus.

Question 313

314 -A patient from South America develops a recurrent fever after living in crowded conditions with multiple roommates having known human body louse infestation. A diagnosis of louse-born Relapsing Fever is made. Which of the following is the implicated organism?

A. Borrelia recurrentis
B. Borrelia duttonii
C. Borrelia hermsii
D. Borrelia burgdorferi
E. Streptobacillus moniliformis

Answer 313

►A

Louse-born relapsing fever is caused by Borrelia recurrentis. It is seen in Africa and South America, and is spread by the human body louse (Pediculus humanus). Symptoms include paroxysmal fevers, headache, myalgias, and petechial macules on trunk and extremities. Borrelia burgdorferi causes Lyme disease; Borrelia duttonii and Borrelia hermsii cause tick-born Relapsing Fever; Streptobacillus moniliformis causes Rat-bite fever.

Question 314

315-A 27 year-old woman who is 30 weeks pregnant presents with erythema migrans. The treatment of choice for this patient is:

A. Doxycycline

B. Erythromycin
C. Chloramphenicol
D. Clindamycin
E. Amoxicillin

Answer 314

►E

In the setting of pregnancy, amoxicillin is the treatment of choice for Lyme Disease since doxycycline is contraindicated.

Question 315

316 -Which of the following HPV types causes a ridged wart?

A. HPV 1
B. HPV 7
C. HPV 11
D. HPV 18
E. HPV 60

Answer 315

►E

HPV 60 infection leads to a particular type of plantar wart called the ridged wart. HPV 1 leads to plantar warts and myrmecia. HPV 7 causes butcher’s warts. HPV 11 along with 6 causes anogenital condyloma and giant condyloma of Bucke and Lowenstein (verrucous carcinoma). HPV 18 causes anogenital dysplasia and neoplasms.

Question 316

317- The most common extracutaneous complications of varicella zoster virus is:

A. Lymphoreticular
B. Musculoskeletal
C. Cardiovascular
D. Central nervous system
E. Genitourinary

Answer 316

►D

Zoster usually resolves without sequelae in children and young adults with intact immune systems. However, the pain, cutaneous eruption and complications of zoster become more severe with increasing age and immune compromise. Complications of zoster include post-herpetic neuralgia (PHN), secondary bacterial infection, scarring, ophthalmic zoster, Ramsay-Hunt syndrome, meningoencephalitis, motor paralysis, pneumonitis and hepatitis.

Question 317

318- Which of the following is a pox virus?

A. Molluscum contagiosum
B. Herpes simplex virus
C. Pediculosis capitis
D. Sarcoptes scabei
E. Human immunodeficiency virus

Answer 317

►A

Of the answer choices, molluscum contagiosum is the only pox virus. Pediculosis capitis, the cause of lice, and sarcoptes scabei, the cause of scabies are not viruses. Herpes simplex virus is a herpes virus and HIV is a lentivirus.

Question 318

319- Where do you see Gamma-Favre bodies?

A. Granuloma inguinale
B. Lymphogranuloma venereum (LGV)
C. Syphilis
D. Chancroid
E. Herpes virus

Answer 318

►B

LGV is a sexually transmitted disease that is characterized by suppurative inguinal adenitis with matted lymph nodes, inguinal bubo with secondary ulceration, and constitutional symptoms. It is caused by Chlamydia trachomatis serotypes L1, L2, and L3. First line treatment is doxycycline 100mg bid for 3 weeks as well as treating the sexual partners. Gamma-Favre bodies are found in histiocytes in LGV.

Question 319

320- An otherwise healthy six-day-old boy is brought into clinic by his mother with the complaint of tiny thin-roofed vesicles with a rim of inflammation and a few lesions covered with a “honeycolored” crust. Which organism is the most likely cause in this newborn?

A. Listeria monocytogenes
B. Group B streptococcus
C. Group D streptococcus
D. Staphylococcus Aureus
E. Lancefield type O organisms

Answer 319

►B

Group B streptococcus is S. agalactae, commonly isolated from normal vaginal mucosa. In neonates, impetigo caused by group B streptococci may develop. Listeria monocytogenes is a small, gram-positive organism that may present as petechial, papular or pustular eruptions in acutely ill infants, usually those that were meconium stained at birth. The usual cause of ecthyma is Group A streptococcus, though other organisms can occasionally cause similar cutaneous infections. Group D streptococcus/Lancefield type O organisms are enterococci. S. aureus can secondarily infect a lesion of ecthyma but is not the usual cause of this condition.

Question 320

321- The leading infectious cause of deafness and mental retardation in the U.S. is:

A. Congenital Rubella
B. Congenital varicella
C. Congenital Cytomegalovirus (CMV)
D. Congenital syphilis
E. Congenital herpes simplex

Answer 320

►C

Congenital CMV is the leading infectious cause of deafness and mental retardation in the U.S.

Question 321

322- A patient with AIDS develops umbilicated papules consistent with molluscum contagiosum. What anatomic sites are favored for molluscum papules in patients with HIV?

A. Face and genitalia
B. Head and neck
C. Abdomen and back
D. Upper and lower extremities
E. Chest and shoulders

Answer 321

►A

Molluscum contagiosum is a common opportunistic infection of HIV patients. Lesions can be seen anywhere, but the most common locations are on the face and genitalia.

Question 322

323- A 56 year old homeless man has many waxy concretions on his axilla and groin hairs. Which of the following organisms is the likely cause?

A. Corynebacterium afermentans
B. Corynebacterium tenius
C. Corynebacterium diptheriae
D. Micrococcus sedentarius
E. Corynebacterium minutissimum

Answer 322

►B

This condition described is trichomycosis axillaris. Despite the “mycosis” in the name, it is not fungal in etiology, but caused by C. tenius. Treatment is topical erythromycin or simply shaving the infected hairs. The other listed organisms do not cause this type of infection.

Question 323

324- Herpes-associated erythema multiforme is most commonly associated with which HLA type?

A. HLA B27
B. HLA DR2
C. HLA DR3
D. HLA B15
E. HLA B8

Answer 323

►D

Recurrent erythema multiforme (EM minor) is usually caused by recurrent herpes simplex, most commonly HSV-1 orolabial disease. This is more correctly now called herpes-associated erythema multiforme(HAEM) and has been more commonly associated with people with HLA type B15.

Question 324

325 -A patient presents with fever, irritability and a scarlatiniform erythema with accentuation in the flexural areas. Nikolsky positive blisters develop within 48 hours. Which of the following would predict the best outcome?

A. Frequent NSAID use
B. Normal renal function
C. Normal immune system
D. Age < 5 years old
E. Age > 18 years old

Answer 324

►D

Staphylococcal scalded skin syndrome is described in the question. This is predominantly a disease of young children, < 5 years old. The mortality is low in children, but in adults it exceeds 50% due to sepsis and electrolyte and fluid imbalance. NSAID use may predispose patients to a poorer outcome. Normal renal function and immune system are helpful, but do not predict the best outcome.

Question 325

326- The most common bacterial cause of purpura fulminans is:

A. S. aureus
B. P. aeruginosa
C. H. influenza
D. E. coli
E. Group A streptococcus

Answer 325

►E

Group A streptococcus and Neisseria meningitidis are the leading bacterial causes of purpura fulminans.

Question 326

327- Which of the following mycobacterial organisms is classified as a photochromogen?

A. M. Kansasii
B. M. grodonae
C. M. fortuitum
D. M. ulcerans
E. M. tuberculosis

Answer 326

►A

M. Kansasii, M. marinum, and M. simiae are photochromogens. They form pigment when exposed to light.

Question 327

328- Which of the following serologic tests for syphilis is the most specific early-on in the disease course?
A. RPR
B. FTA-Abs
C. MHA-TP
D. ELISA - Captia (IgM) EIA
E. VDRL

Answer 327

►D

ELISA - Captia (IgM) EIA is 100% specific for treponemes and is the serology of choice in early primary or congenital syphilis because it is the first to become reactive. FTA-Abs is the most sensitive serologic test for syphilis and MTA-TP stays positive for life (but is less sensitive than FTA-ABs during early disease). The two nontreponemal tests for syphilis include VDRL and RPR. VDRL is used to follow response to therapy.

Question 328

329- A 36 year-old homeless man presents with a tender suppurative nodule on the mandible. “Sulfur granules” are present on microscopy. The most likely diagnosis is:

A. Actinomycetoma
B. Actinomycosis
C. Anthrax
D. Acne Conglobata
E. Aspergillosis

Answer 328

►B

The presentation of a suppurative nodule discharging sulfur granules on the jawline of a patient with poor oral hygeine is characteristic of actinomycosis - caused by the anaerobic gram-positive rod, Actinomyces israelii. This differs from Actinomycetoma, which is a slowly progressive subcutaneous infection characterized by tumefaction, draining sinuses, and an exudate containing grains on microscopy. Unlike Eumycetomas - caused by fungi - Actinomycetomas are bacterial infections. The foot is the most common location, followed by the thoracic area.

Question 329

330- A child presents with fever, cutaneous tenderness and erythema of flexural and periorifacial areas. Within 24 hours the erythema progresses to flaccid blisters and erosions. No organisms are cultured and Nikolsky’s sign is positive. What is the most likely diagnosis:

A. Staph scalded skin syndrome
B. Bullous impetigo
C. Fogo selvagem
D. Pemphigus
E. Pemphigoid

Answer 329

►A

Staph scaled skin syndrome is caused by exfoliative toxins A and B (ET-A and ET-B) produced by
S. aureus (phage group II, types 71 and 55 most common). Histopathology of the skin shows superficial intraepidermal splitting without epidermal necrosis with very few inflammatory cells. Desmoglein 1 is the specific receptor for exfoliative toxin A cleavage. Desmoglein 1 is the antigen targeted in Fogo selvagem, the vector for which is the black fly. Bullous impetigo is caused by Staph and is a subgranular blister with bacteria and neutrophils on histopahtology. Pemphigoid and pemphigus would be less likely in a child.

Question 330

331- Which antibiotic is best to treat this condition caused by Bartonella hensalae.

A. Erythromycin
B. Ceftriaxone
C. Clindamycin
D. Trimethoprim/sulfamethoxasole
E. Fluconazole

Answer 330

►A

Bartonella hensalae is the causative agent of bacillary angiomatosis. The differential diagnosis of bacillary angiomatosis may include pyogenic granulomas and Kaposi’s sarcoma. The treatment of choice is erythromycin.

Question 331

332- Most common causative agent for the lesion immunocompetent man is shown in image for this 34-year old

A. Staphaylococcus aureus
B. Group A Beta hemolytic streptococcus
C. Pseudomonas aeruginosa
D. Klebsiella
E. Proteus

Answer 331

►B

Ecthyma is a deep or ulcerative type of pyoderma commonly seen on the lower extremities and buttocks and caused most often by GABHS, in addition to staphyloccous aureus which also can be involved in the infection. Ecthyma can present as small punched-out ulcers or a deep spreading ulcerative process. The disorder begins in the same manner as impetigo, often following infected insect bites or minor trauma, but penetrates through the epidermis to produce a shallow ulcer. The initial lesion is a vesiculopustule with an erythematous base and firmly adherent crust. Removal of the crust reveals a lesion deeper than that seen in impetigo, with an underlying saucer-shaped ulcer and raised margin. The lesions are painful and heal slowly over a few weeks, often with scar formation. Ecthyma gangrenosum is a cutaneous finding that may be seen in patients with Pseudomonas aeruginosa bacteremia. Most of the affected individuals have an underlying immunodeficiency (either congenital or acquired) or a history of cancer chemotherapy. Neutropenia may be a risk factor for ecthyma gangrenosum

Question 332

333- Unilateral palpebral and periorbital edema is characteristic of which of the following infectious diseases?

A. African trypanosomiasis
B. American trypanosomiasis
C. Amebiasis
D. Schistosomiasis
E. Onchocerciasis

Answer 332

►B

American trypanosomiasis (Chagas‟ disease) is caused by infection with Trypanosoma cruzi via Triatoma arthropod vectors (reduviid bugs) and is prevalent predominantly in Central and South America. Transmission of this protozoal infection may occur following the bite of an infected reduviid bug, who then defecates on human skin after feeding, allowing the metacyclic trypomastigotes entry into the bite wound. Alternatively, infected feces may gain direct entry through mucosal surfaces, including the conjunctivae. When the latter occurs, characteristic unilateral palpebral and periorbital edema ensues, known as “Romana‟s sign.” Entry into the skin may result in a localized plaque of erythema and induration with regional lymphadenopathy, termed a “chagoma.” Other systemic complications resulting from chronic infection include cardiac arrhythmias, congestive heart failure, megacolon, and megaesophagus. Treatment is with nifurtimox or benznidazole.

Question 333

334- What is the following is the best choice for treatment of herpes zoster?

A. Ganciclovir
B. Foscarnet
C. Valacyclovir
D. Gabapentin
E. Cidofovir

Answer 333

►C

First line treatment of herpes zoster (shingles) is with valacyclovir, acyclovir, or famciclovir. Gabapentin may be used for post-herpetic neuralgia. Cidofovir and ganciclovir are treatment options for cytomegalovirus. Foscarnet is used to treat acyclovir resistant herpes simplex infections.

Question 334

335- Which of the following is true regarding the Gardasil vaccine?

A. It is a live vaccine
B. It is FDA approved for females aged 18 to 25
C. It protects against HPV 16 and 18 only
D. It can be administered regardless of history of abnormal pap smear

E. It does not protect against genital warts

Answer 334

►D

Gardasil is a quadrivalent vaccine containing HPV types 6, 11, 16 and 18. It is approved for females ages 9 to 26. Neither HPV testing nor pap smears are necessary before vaccine administration. It is recommended for the prevention of cervical, vaginal, and vulvar cancers, as well as for genital warts.

Question 335

336- Non tuberculosis mycobacterial infections include M. marinum treatment would include:

A. Clarithromycin
B. Cephalosporin
C. Penicillins
D. Quinolones
E. Azithromycin

Answer 335

►A

M. marium is also known as fish tank granuloma. Empiric therapy is suggested with M. marinum infection and the first line treatment is minocycline, #2 is clarithromycin.
c

Question 336

337 -American trypanosomiasis is transmitted by humans via reduviid or kissing bugs. It is caused by:
A. Trypanosome cruzi
B. Toxoplasma gondii
C. Pneumocystis carinii
D. Entamoeba histolytica
E. Tamandua tetradactyla

Answer 336

►A

African trypanosomas is also known as sleeping sickness and is caused by Trypanosoma brucei and transmitted by the tsetse fly Glossina. It can occasionally have cutaneous manifestations such as chancre and trypanids.

Question 337

338- Streptobacillus moniliformis is the causative organism of which infectious disease?

A. Rat-bite fever (Haverhill fever)
B. Scrub typhus
C. Tularemia
D. Glanders
E. Cat scratch disease

Answer 337

►A

Rat-bite fever (Haverhill fever) is caused by Streptobacillus moniliformis.

Question 338

339- Which of the following is the causative organism of Tularemia?

A. Burkholderia mallei
B. Streptobacillus moniliformis
C. Francisella tularensis
D. Orientia tsutsugamushi
E. Klebsiella pneumoniae
c

Answer 338

►C

Tularemia is caused by infection with Francisella tularensis - most commonly acquired after contact with infected rabbits (e.g. hunters).

Question 339

340- A woman who handles fish tanks develops a slow-growing cluster of papules on the hand. What temperature (Celsius) is most optimal for this organism’s growth?

A. 25 degrees
B. 30 degrees
C. 37 degrees
D. 40 degrees
E. 42 degrees

Answer 339

►B

This patient most likely has contract Mycobacterium marinum, otherwise known as “fish tank granuloma.” On primary isolation M. marinum grows best at 30-33 degrees C in 7-21 days. Unlike Mycobacterium tuberculosis, most strains of M. marinum will not grow at the usual incubation temperature of 37 degrees C. Dimorphic fungi have both yeast and fungal forms: hyphae morphology at 25 degrees C and yeast phase at 37 degrees C.

Question 340

341- A patient recently had pharyngitis and now has an eruption of guttate psoriasis. Which of the following tests would be helpful in determining that this patient had a Streptococcal infection?

A. A complete blood count
B. FTA-ABS
C. U1-RNP
D. DNAse B
E. Serum calcium

Answer 340

►D

The DNAse B, hyaluronidase or streptolysin O (ASLO) antibodies in serum can be helpful for confirming streptococcal infection in situations where streptococci cannot be isolated. The FTA ABS is used for detecting syphilis, and is the only test that is positive in the first 14 days of infection. U1-RNP is an extractable nuclear antibody which is a marker for Mixed Connective Tissue Disease.

Question 341

342- At what rate of speed does this parasite migrate through the skin?

A. 0.1 cm/day
B. 1 cm/day
C. 2 cm/day
D. 10 cm/day
E. 100 cm/day

Answer 341

►C

The infection depicted is larva migrans or creeping eruption which is caused by Ancylostoma braziliense. This nematode is typically a hookworm of cats and dogs. It migrates at a rate of 2 cm/ day. Larva currens migrates at a rate of 10 cm/day.

Question 342

343- A male patient experiences painful vesicles on the palate, tongue, and ipsilateral eardrum. Additionally, he complains of vertigo and difficulty with speaking and eating. Involvement of what anatomic structure is responsible for this constellation of symptoms?

A. Geniculate ganglion
B. Dorsal root ganglion
C. Hippocampus
D. Basal portion of pons
E. Hypoglossal nerve

Answer 342

►A

The question stem describes Ramsay-Hunt syndrome, which is characterized by unilateral vesicles on palate, tongue, earlobe, and eardrum, in association with neurologic symptoms including vertigo, difficulty speaking, difficulty eating, hearing loss, and facial droop. The syndrome is caused by varicella-virus infection of the geniculate ganglion.

Question 343

344- A 37-year-old man presents with a red, tender papule on his lateral right hand that subsequently becomes necrotic with regional lymphadenopathy. An exanthem is also present. Which animal was this individual hunting?
A. Rabbits
B. Grouse
C. Squirrels
D. Deer
E. Moose

Answer 343

►A

The presentation described above is that of Tularemia, caused by Francisella tularensis. The most common form of Tularemia is the ulceroglandular form, which is described above. Infected animals, most commonly rabbits, transmit the organism though occasionally tick bites or deer flies may be the vector. Squirrels may be the vector of bubonic plague in endemic areas. The other animals would not cause a syndrome as described.

Question 344

345- Which of the following Rickettsial diseases would be rarely positive on Weil-Felix test?

A. Rocky Mountain Spotted Fever
B. Epidemic Typhus
C. Rickettsial pox
D. Endemic typhus
E. Scrub Typhus

Answer 344

►C

Rickettsial pox is diagnosed by clinical suspicion and confirmatory biopsy, the Weil -Felix test is rarely positive. The other listed Rickettsial diseases will have positive Weil-Felix tests. The Weil- Felix test makes use of the cross-reaction between antigens from the gram-negative Proteus vulgaris species and Rickettsia spp. It is not specific and rising titers in the appropriate clinical presentation is necessary for confirmation. The Proteus antigens OX-K, OX-19 and OX-2 are employed.

Question 345

346- A 10 year-old with a 3-day history of fever and headache presents to the clinic with multiple erythematous papulopustules on his extremities, many of which have central eschars. The most likely diagnosis is:

A. Lyme disease
B. Rickettsialpox
C. Erlichiosis
D. Rocky mountain spotted fever
E. Meningococcemia

Answer 345

►B

Rickettsialpox is an acute febrile illness caused by the bacteria Rickettsia akari, a member of the spotted fever group. R. akari is transmitted by the house mouse mite, Liponyssus sangineus. Clinically, patients have an eschar at the inoculation site with a subsequent papulovesicular rash, fevers, headache, chills, diaphoresis, myalgia, and anorexia.

Question 346

347- There are four clinical signs of granuloma inguinale and one can see Donovan bodies on microscopy. Granuloma inguinale is caused by:

A. Klebsiella granulomatis
B. Chlamydia trachomatis
C. H. ducreyi
D. T. pallidum
E. Pseudomonas aeruginosa

Answer 346

►A

Granuloma inguinale is caused by Klebsiella (old name: Calymmatobacterium) granulomatis. The primary lesions are pseudobubo or ulcer. There are four clinical forms: ulcerovegetative, nodular, hypertrophic, and cicatricial. Donovan bodies are seen on microscopy.

Question 347

348- The usual cause ecthyma is:

A. Group A streptococcus
B. Group B streptococcus
C. Group D streptococcus

D. Staphylococcus Aureus
E. Lancefield type O organisms

Answer 347

►A

The usual cause of ecthyma is Group A streptococcus, though other organisms can occasional ly cause similar cutaneous infections. Group B streptococcus is S. agalactae, commonly isolated from normal vaginal mucosa. Infections can be problematic for neonates, but not a frequent cause of ecthyma. Group D streptococcus/Lancefield type O organisms are enterococci. S. aureus can secondarily infect a lesion of ecthyma but is not the usual cause of this condition.

Question 348

349- Which of the following is the vector for Dengue fever?

A. Phlebotomus papatasii
B. Culex mosquito
C. Aedes aegypti
D. Lutzomyia verrucarum
E. Xenopsylla cheopis

Answer 348

►C

Dengue fever also known as “break-bone” fever is characterized by sudden high fever, backache, retro-orbital pain, bone/joint pain, weakness, and malaise. It is caused by an arbovirus (RNA virus) which is transmitted by Aedes aegypti, a species of mosquito.

Question 349

350- What is the most common cause of focal epithelial hyperplasia?

A. Ebstein Bar virus(EBV)
B. Pachyonychia Congenita
C. human immunodeficiency virus(HIV)
D. human papilloma virus(HPV)
E. Dyskeratosis Congenita

Answer 349

►D

Focal epithelia hyperplasia, also known as Heck’s disease, is caused by HPV types 13, 32 and 57. It is most commonly found on the lower lip but also on the buccal mucosa, gums and tongue. It is mainly a disease of native Americans and Greenlander Eskimos. EBV causes an oral hairy leukoplakia in patients with AIDS. Pachyonychia Congenita patients commonly develop a benign oral leukoplakia, while Dykeratosis Congenita patients develop a premalignant oral leukoplakia.

Question 350

351- Tricomycosis axillaris is caused by:

A. Burkholderia mallei
B. Proteus species
C. Corynebacterium tenuis
D. Micrococcus sedentarius
E. Corynebacterium minitissimum

Answer 350

►C

Corynebacterium tenuis is the causative organism associated with most cases. Although up to 33% of adults have colonization by this bacterium in the inguinal or axillary regions, factors such as hyperhidrosis predispose to more extensive growth and resultant clinical manifestations.

Question 351

352- What is the classic CXR finding of a patient with inhalational anthrax?

A. Alveolar infiltrates
B. Increased interstitial markings
C. Pleural effusions
D. Widened mediastinum
E. Normal x-ray

Answer 351

►D

Inhalation anthrax is the most lethal form of anthrax. Other forms include cutaneous anthrax and GI anthrax. The classic radiographic finding is a widened mediastinum.

Question 352

353- A 21 year old female with a family history of C8 complement deficiency presents with sparsely distributed hemorrhagic vesiculopustules on the palms, soles, and over joints. She has associated fever, chills, arthralgias, and malaise. What is the treatment of choice for disseminated gonococcemia?

A. Ceftriaxone IV
B. Penicillin IM
C. Piperacillin-tazobactam IV
D. Levofloxacin PO
E. Azithromycin

Answer 352

►A

Gonococcemia is characterized by sparsely distributed hemorrhagic vesiculopustules on the palms, soles, and over joints with associated fever, chills, arthralgias, and malaise. Recurrent cases associated with complement deficiencies (C5-C8). Treatment is with IV ceftriaxone.

Question 353

354- What is the most common single nerve involved with herpes zoster?

A. Facial nerve
B. Trigeminal nerve
C. Spinal nerve C7
D. Spinal nerve T4
E. Spinal nerve T10

Answer 353

►B

While herpes zoster can be seen in the dermatome of any cranial or spinal nerve, the most common single nerve involved is the trigeminal nerve.

Question 354

355- Hebra nose deformity is characteristic of infection with which organism?

A. Klebsiella pneumoniae
B. E. coli
C. Streptococcus pyogenes
D. Haemophilus influenzae
E. Serratia marcesens

Answer 354

►A

Hebra nose deformity is seen in Rhinoscleroma which is caused by Klebsiella pneumoniae subspecies rhinoscleomatis.

Question 355

356- A 52 year-old butcher presents with a tender lesion on his left hand as shown. The treatment of choice for this condition is:

A. Penicillin
B. Azithromycin
C. Ciprofloxacin
D. Tetracycline
E. Chloramphenicol

Answer 355

►A

The clinical description and lesion shown in the image suggest a diagnosis of erysipeloid, caused by Erysipelothrix rhusiopathiae. The treatment of choice is penicillin.

Question 356

357- A laboratory worker undergoes injection of vaccinia virus for vaccination against smallpox. What type of reaction is needed to ensure adequate development of immunity?

A. Vesicle or ulcer surrounded by 4 cm of erythema
B. Lichenoid plaque
C. Development of vesicles at site separate from injection
D. Targetoid plaque
E. Systemic flu-like reaction with fever and myalgia

Answer 356

►A

Vaccinia virus is used to vaccinate high-risk individuals against smallpox virus. Development of a vesicle or ulcer with 4 cm of surrounding erythema is a reaction considered to have a high rate of adequate immunization.

Question 357

358- What is the risk of transmission of HSV from active cervical lesions when a C-section is performed?

A. 1%
B. 8%
C. 17%
D. 31%
E. 43%

Answer 357

►A

When a C-section is performed in the setting of active cervical lesions of HSV, the risk of maternal- fetal transmission is decreased to 1%. If a child were delivered

Question 358

359- A pool worker develops these painful erythematous nodules with ulceration on his fingers and then his arms. The antibiotic of choice to treat this infection is:

A. Penicillin
B. Ceftriaxone
C. Minocycline
D. Trimethoprim-sulfamethoxasole
E. Cephalexin

Answer 358

►C

Sporotrichoid spread may be seen in cutaneous leishmaniasis, actinomycosis, atypical mycobacterial infections, deep fungal infection, and melanoma. Mycobacterium marinum is associated with skin injury followed by exposure to contaminated water, usuall y from an aquarium, lake, or pool. The treatment of choice for M. marinum infections is minocycline.

Question 359

360- A 25-year old male from Egypt complains of slowly enlarging chronic growths on his external nares that are causing nasal obstruction. Biopsy reveals Mikulicz cells on histopathology. Which of the following medications would be most appropriate for treatment of these lesions?

A. Ciprofloxacin
B. Penicillin
C. Erythromycin
D. Trimethoprim-Sulfamethoxazole
E. Imipenem

Answer 359

►A

This patient has rhinoscleroma, a chronic granulomatous infection of the nose and upper respiratory tract by Klebsiella pneumoniae rhinoscleromatis. The disease is endemic in Africa, Southeast Asia, Mexico, Central and South America, and Central and Eastern Europe and is rarely reported in the

United States. Presentation may vary from rhinitis to diffuse airway obstruction. Mikulicz cells are foamy, vacuolated macrophages seen in rhinoscleroma. Antibacterial therapeutic choices include ciprofloxacin, tetracycline, and rifampin. Surgical treatment may be required for obstructive lesions.

Question 360

361 -A patient has a granulomatous plaque that is diagnosed as swimming pool granuloma. The treatment for this is:

A. Minocycline
B. Ampicillin
C. Thalidomide
D. Penicillin
E. Rifampin

Answer 360

►A

Swimming pool granuloma or fish tank granuloma is caused by M. marinum and begins as a small plaque at the site of inoculation and evolves to a granulomatous plaque. It occurs as a sporotrichoid spread. The treatment is minocycline.

Question 361

362 -Pediculus humanus corporis can transmit:

A. Murine typhus
B. Epidemic typhus
C. Scrub typhus
D. Endemic typhus
E. Oriental typhus

Answer 361

►B

The body louse or Pediculus humanus corporis transmits Rickettsia prowasekii the organism responsible for epidemic typhus. Endemic typhus or murine typhus is caused by R. typhi that is transmited by the rat flea/Xenopsylla cheopis. Scrub typhus is caused by R. tsutsugamushi and is transmitted by chiggers or trombiculid mite larvae.

Question 362

The causative organism in Whitmore disease is which of the following?

A. Streptobacillus moniliformis
B. Vibrio vulnificus
C. Klebsiella pneumoniae
D. Pseudomonas aeruginosa
E. Burkholderia pseudomallei

Answer 362

►E

Whitmore disease also known as Melioidosis is characterized by pulmonary disease, septicemia, and miliary abscesses. It is caused by Burkholderia pseudomallei.

Question 363

364 -All of the following are features of the Ramsay Hunt Syndrome EXCEPT:

A. Tinnitus
B. Facial paresis
C. Vesicles on the external ear
D. Herpes simplex infection
E. Infection of the geniculate ganglion

Answer 363

►D

Ramsay Hunt syndrome results from varicella zoster virus infection of the geniculate ganglion of the seventh cranial nerve (CN VII). It is characterized by vesicles on the external ear or ear canal, tinnitus and/or other auditory symptoms, and ipsilateral facial paresis.