Infectious disease Chapter 5 Flashcards
Phenolic glycolipid-1 is important in identification of?
Mycobacterium Leprae
In patients with hepatitis C viral infections treated with interferon, appearance of what skin disease has been most commonly reported?
Sarcoidosis
Components in HPV important for binding/
entering epithelial cells?
L1 (major structural protein) and L2 (minor structural protein)
What proteins are responsible for HPV DNA replication and keratinocyte immortalization?
Early proteins E1–E7
What HPV proteins are expressed in superficial epidermis and encode structural proteins required for virion formation?
Late proteins (L1–L2)
What strains are in Butchers warts?
HPV-7 and HPV-2
HPV high-risk mucosal subtypes?
E6 and E7 in high-risk mucosal subtypes are oncoproteins.
- E6 -> ubiquitin-mediated p53 destruction -> decrease apoptosis, increase replication, increase mutations
- E7 -> binds RB -> loss of inhibition of E2F transcription factor -> increase expression of genes important for DNA replication
Which genus of HPV is mucosal , cutaneous and which is epidermal
Genus alpha (most of the mucosal and cutaneous HPV types) and beta (epidermodysplasia verruciformis [EV]- associated HPV types)
Palmar/plantar warts, HPV?
HPV-1, HPV-2, -4*, -27, and -57. Vs flat/plane (3,10,28)
Histology: “church spire” papillomatosis + hyperkeratosis, acanthosis (with elongated rete ridges), hypergranulosis, koilocytosis (granular layer); h dermal vessels
Flat/plane warts, HPV?
HPV-3, -10, -28, and -29.
Ridged warts retain normal dermatoglyphics strain?
HPV-60
Autosomal recessive disorder where host has susceptibility to genus b HPV types (HPV-3, -5, -8, -9, -12, -14, -15, -17, -19–25, -36–38, -47, -49)?
Epidermodysplasia verruciformis; mutations in TMC6 (EVER1) and TMC8 (EVER2) (encode transmembrane proteins in endoplasmic reticulum, which interact with Zn transporter 1 -> decreases Zn intracellularly -> decreases Zn-associated transcription factors); Acquired form may be seen in HIV
What is WHIM syndrome?
Immunodeficiency caused by a CXCR4 mutation— Autosomal dominant
Warts
Hypogammaglobulinemia
Infections (bacterial)
Myelokathexis (= a defective release of BM cells into the peripheral blood; causing neutropenia)
What is WILD syndrome?
Warts
Immunodeficiency
Lymphedema
Dysplasia
Dew drop on a rose petal is seen in:
Chicken pox
What is Buschke-Lowenstein tumor?
HPV-6 and HPV-11, cauliflower-like tumors that infiltrate deeply on external genitals and perianally
Red smooth plaque on glabrous penis/vulva that is HSIL or SCCIS; increased risk of progression to invasive SCC; has high-risk HPV types, called?
Erythroplasia of Queyrat
Epithelioma cuniculatum?
Is a keratinizing carcinoma the sole, HPV-2, -11, and -16
Heck’s disease?
HPV-13 and 32
How does HSV evade the immune system?
HSV decreases expression of CD1a by antigen-presenting cells [APCs], increases Langerhans cells apoptosis, decreases TLR signaling, interferes w/ MHC class I/II); CD8+ T cells and TLRs control infection
Herpes gladiatorum?
HSV-1 infection 2° to athletic contact, classically on lateral neck, side of face and forearm.
Branching dendritic corneal ulcer?
Ocular HSV
Biologic associated with increased risk of HSV encephalitis?
Natalizumab - indicated for Crohn’s + MS
Bodies seen in HSV?
Cowdry A inclusions = eosinophilic inclusion
bodies
Tx of acyclovir-resistant HSV?
Foscarnet or cidofovir
HHV-3 causes?
Varicella (chickenpox) and Herpes zoster (shingles)
Death in disseminated herpes zoster immunocompromised patients?
SIADH development
Which CN is affected by herpes zoster that results in hearing impairment or deafness?
CN-VIII - Vestibulocochlear nerve
Ramsay Hunt syndrome affects which nerve?
Disease of the geniculate ganglion of facial nerve (CN-VII). Causing ipsilateral facial nerve paralysis, dry mouth/ eyes, anterior two thirds of the tongue taste loss, and auditory (e.g., deafness and tinnitus).
Hutchinson’s sign in herpes zoster ophthalmicus is?
Involvement of the side and tip of nose indicates disease of the external division of the V1 nasociliary branch
Reye’s syndrome?
Encephalitis + fatty liver, with
concomitant aspirin use
What type of HHV is EBV?
HHV-4; Causes infectious mononucleosis, oral hairy leukoplakia, hydroa vacciniforme, Gianotti-Crosti syndrome, genital ulcers, Burkitt’s lymphoma, NK/T-cell lymphoma, post- transplant lymphoproliferative disorder, and nasopharyngeal carcinoma.
How is EBV transmitted?
Saliva and blood. EBV infects B cells via CR2/CD21 receptors.
Gianotti-Crosti syndrome and papular-purpuric glove and socks syndrome due to what virus?
More common w/ parvovirus B19, may occur in setting of Epstein-Barr virus (EBV) infection
What does Monospot test detect?
IgM heterophilic antibodies which are often present in EBV infection and may persist for months after infection; Positive heterophilic antibody (>1:40) and >10% atypical lymphocytes suggests acute infection
What is HHV-5?
Cytomegalovirus
First -line for CMV?
Ganciclovir (IV) and valganciclovir (oral)
HHV-6?
Roseola infantum
assoc. w/ Pityriasis Rosea, Rosai-Dorfman and DRESS syndrome
DRESS syndrome associated with?
HHV-6, EBV, CMV and HHV-7
HHV-8 etiologic factor for?
Kaposi sarcoma, multicentric Castleman disease, primary effusion lymphoma, and paraneoplastic pemphigus
S/E of smallpox vaccine?
LAD, ocular vaccinia, generalized vaccinia, single crusted papule at vaccination site, vesiculopustular, urticarial/morbilliform eruption, eczema vaccinatum (patients with atopic dermatitis, Darier, or Hailey- Hailey disease), EM/SJS, postvaccinial CNS disease, and progressive vaccinia (immunosuppressed patients; can cause death)
Cowpox vs. Orf?
Cowpox - Orthopox
Orf - Parapox
Orf paradox 6 lesions stages?
1- Maculopapular (umbilicated)
2- Targetoid
3- Acute (weeping nodule)
4- Regenerative (nodule w/ thin crust and black dots)
5- Papillomatous
6- Regressive (crust overlying resolving lesion) then self-resolves
Histology of Orf?
Intracytoplasic eosinophilic inclusion bodies, keratinocyte vacuolization, epidermal necrosis, finger-like acanthosis
What are Milker’s nodules?
“Pseudocowpox” papules at the site of contact (usually muzzles of calves and teats of cows
Chikungunya virus?
Single-stranded +sense RNA virus belonging to Togaviridae family
Chikungunya virus transmitted by?
Aedes aegypti
Chikungunya virus px?
High fever, marked joint symptoms, “Chikungunya” is an African word for “crooked/bent joints”, and neuropathic acral findings.
Skin: morbilliform eruption, mucosal aphthous-like ulcers, postinflammatory pigmentation of face/extremities
Zika virus?
ssRNA virus within the Flaviviridae family
Zika virus transmitted by?
A. aegypti and A. albopictus mosquitos
Classic cutaneous manifestation of Hepatitis B?
Polyarteritis nodosa. Also, Urticarial vasculitis, Urticaria, Erythema multiforme, Porphyria cutanea tarda, Pruritus
HIV is?
ssRNA in retroviridae family (HIV-1 > HIV-2 in causing AIDS)
Tx of choice for Erythema elevatum diutinum?
Dapsone
HIV most at risk of developing which carcinoma?
BCC > SCC > melanoma
HIV-associated disorders CD4+ <50?
Giant Mollusca, MAC, CMV-perianal ulcers, Large non-healing mucocutaneous HSV, papular pruritic eruption
HIV-associated disorders CD4+ <250?
Bacillary angiomatosis, Eosinophilic folliculitis, Seborrheic dermatitis, Cryptococcosis, Histolasmosis, Coccidioidomycosis, Botrymycosis, extensive Mollusca, Disseminated HSV
HIV-associated disorders CD4+ <500?
Kaposi sarcoma, Oropharyngeal candidiasis, herpes zoster, psoriasis, eruptive atypical melanocytes nevi
filler types for HIV-associated facial lipoatrophy?
Poly-L-lactic acid and calcium hydroxylapatite are approved for tx
Most common antiretroviral to cause DRESS?
Abacavir, others include: efavirenz, nevirapine, TMP-SMX, and dapsone
HLA associated with Abacavir HSRxn?
HLA-B*5701, screen patients before initiating therapy
Bullous impetigo is due to?
Phage group II (types 55* and 71*) S. aureus produces exfoliatoxins A and B (ETA and ETB) cleaveing desmoglein 1 causing subcorneal/ intragranular acantholysis
Acquired hypertrichosis lanuginosa is associated with?
Lung cancer, Colon cancer, Breast cancer and Plamoplanter keratoderma
The Brunsting- perry variant of cicatricial pemphigoid:
Is localized to the head and neck
Langerin stain AKA?
CD207 NOT CD117 (mast cells)
Tx of widespread Bullous impetigo?
Oral b-lactamase–resistant PCN or first- generation cephalosporin (CSN; clindamycin or clarithromycin if PCN-allergic)
Non-bullous impetigo caused by?
S. pyogenes serotypes 1, 4, 12, 25, and 49. Poststreptococcal glomerulonephritis in 5%.
Name given to superficial form of S. aureus folliculitis?
Bockhart’s impetigo: small papulopustules on erythematous background
Name given to deep form of S. aureus folliculitis?
“sycosis barbae”: large red papulopustules +/– plaques with small pustules
Tx for pseudomonal folliculitis, from poorly chlorinated hot
tubs?
self-resolves; ciprofloxacin if severe
Gram -ve folliculitis tx?
Isotretinoin
Primary site for furuncles?
Head and neck
Definition of carbuncle?
Collection of furuncles, often deeper w/ multiple draining sinuses; most often affects thick skin of posterior neck, back, and thighs. Tx: doxycycline, TMP-SMX, and clindamycin.
MRSA pathogenesis?
Resistance: specific mecA genes* (from SCCmec types I–VI, mobile genetic elements) encodes mutated penicillin- binding protein, PBP2a* decreasing affinity for b-lactams
Virulence factor in community-associated MRSA?
Panton-Valentine leukocidin (PVL) virulence factor
Pathogenesis of Staphylococcal toxic shock syndrome (TSS)?
Production of toxic shock syndrome toxin-1 (TSST-1) by certain strains of S. aureus. TSST-1 acts as superantigen, binding to Vb region of TCR and class II MHC on APCs. Nonspecific activation of T cells 1 cytokine storm (increased TNF-a, IL-1, IL-6, TLR2, and TLR4)
Toxic shock syndrome (TSS)? tx?
b-lactamase–resistant antibiotics, clindamycin (suppresses toxin production)
What’s Pyomyositis?
S. aureus infection of skeletal muscle; usually have predisposing factors (immunosuppression, diabetes, trauma, and intravenous drug abuse [IVDA])
How to dx Pyomyositis?
MRI
What’s Botryomycosis?
Deep granulomatous and suppurative infection most frequently caused by S. aureus
Splendore-Hoeppli phenomenon?
Seen in histology of botromycosis. Histology: large granules w/ basophilic center (non-filamentous bacteria) and eosinophilic/hyaline periphery (Splendore-Hoeppli phenomenon; composed of IgG and C3 deposits), granules are surrounded by abscess and granulomatous inflammation, granules are PAS+, Giemsa+, and Gram+
Ecthyma is?
Deep variant of impetigo; most common in children; caused by S. pyogenes
p/w few vesicopustules, most commonly on legs n develop into “punched-out” ulcers with purulent base and hemorrhagic crust n slowly self-resolves w/ scarring
Tx for Perianal streptococcal skin infection?
Oral cefuroxime (1st-line) or PCN (slightly less effective)
Erythrasma is caused by?
Corynebacterium minutissimum (Gram- positive filamentous rod) vs. Corynebacterium tenuis seen in Trichomycosis axillaris
Erythrasma fluoresces “coral red” w/ Wood lamp due to?
Coproporphyrin III production
Pitted keratolysis is caused by?
Kytococcus sedentarius
Microbiology of Actinomyces israelii?
Gram-positive, non-acid fast, and anaerobic filamentous bacteria
Microbiology of Nocardiosis?
Gram-positive, weakly acid-fast, filamentous bacteria, AFB+, Fite > Ziehl-Neelsen and GMS+
Microbiology of Bacillus anthracis?
Gram-positive, spore-forming rod
Px of Bacillus anthracis?
“malignant pustule” that drains serosanguinous fluid, vesicle ulcerates to form painless/black/necrotic eschar w/ satellite vesicles and edema
The green in green nail syndrome?
Pyocyanin pigment production
Blue-green purulent exudate, “moth-eaten” appearance to skin surface, with “mousy” or “grape-like” odor?
Pseudomonal pyoderma
Cutaneous lesion indicative of P. aeruginosa septicemia?
Ecthyma gangrenosum
Dense neutrophilic infiltrate, and extra- and intracellular organisms (within endothelial cells—Rocha-Lima inclusions) seen w/ Warthin-Starry stain is?
Bacillary angiomatosis and verruga peruana
Culturing Bartonella?
B. bacilliformis—PCR, culture, immunologic testing
B. henselae and B quintana—PCR assay (rapid, sensitive), serologies (sensitive, specific; not for B. quintana), chocolate agar culture (slow!)
Typhus group?
R. typhi and R. prowazekii
Scrub typhus?
R. tsutsugamushi
Spotted fever group?
R. rickettsii, R. conorii, R. akari, R. africae, R. japonica, and R. australis
Tx for Carrion’s disease?
= Bartonellosis, 1st-line Chloramphenicol plus b-lactam antibiotic
Mediterranean spotted fever vector?
Rhipicephalus sanguineus (brown dog tick)
Tx for pregnant woman with RMSF?
Chloramphenicol is treatment of choice for pregnant patients but risk of “gray baby syndrome”
Rickettsialpox vector?
Liponyssoides sanguineus (house mouse mite). Px w/ papulovesicle at bite site then progresses to eschar then widespread cutaneous eruption
Epidemic typhus vs. Endemic typhus vector?
Epidemic - Pediculus humanus var. corporis (human body louse)
Endemic - Xenopsylla cheopis (Oriental rat flea)
p/w Fever + similar systemic symptoms as spotted fever group + erythematous macules and papules initially on axillae?
Typhus group always starts in axilla. This px is specifically Endemic typhus
Tx for typhus?
Doxycycline in all types of typhus
Scrub typhus AKA?
Orientia tsutsugamushi transmitted by the Larval trombiculid mites* “chiggers”
Most common in Southern United States; p/w fever, myalgias, thrombocytopenia, leukopenia, and maculopapular or petechial rash (30%–40%) most commonly on trunk, extremities?
Human monocytic ehrlichiosis (HME)
(Ehrlichia chaffeensis) <– this is a rickettsia-like bacteria
Reservoir for Human monocytic ehrlichiosis (HME) (Ehrlichia chaffeensis)?
white-tailed deer (no eschar seen)
Ixodes scapularis and Ixodes pacificus (same as Lyme and Babesiosis) also transmit?
Human granulocytic anaplasmosis (Anaplasma phagocytophilum)
Q fever AKA?
Coxiella burnetii - transmitted by sheep and cattle
Main virulence factor in mennigiococcemia?
polysaccharide capsule* and the endotoxin* causes septic shock and purpura fulminans
Neisseria meningitides (gram-negative diplococcus) Quadrivalent vaccine protects against?
Types A/C/Y/W-135
Microbiology of Brucellosis (Malta fever)?
Gram-negative coccobacillus
What can you get from infected horses, mules, or donkeys?
Glanders caused by gram-negative bacillus, Burkholderia mallei.
What are the 4 forms of Glanders?
1- “Localized” - hemorrhagic, ulcerative papulopustule at inoculation site
2- “Chronic” - multiple soft tissue nodules “farcy buds”* on skin overlying lymphatics
3- “Septicemic form” - mortality rate 95% without treatment and 50% w/ treatment
4- “Pulmonary form—mortality similar to septicemic form
Gram-negative bacillus Burkholderia pseudomallei causes?
Melioidosis caused by direct contact w/ contaminated water or soil
Risk factors of Melioidosis?
Diabetes, CKD, immunosuppression, and IV drug abuse
Chronic granulomatous infection as a result of the inability of macrophages to kill phagocytosed E. coli, usually in immunocompromised, causes?
Malakoplakia
Malakoplakia usually affects what areas?
Most commonly affects GU tract; may affect skin of perianal/genital region (ulcerated abscesses and soft polypoid lesions)
Michaelis-Gutmann bodies seen with granulomatous malakoplakia around the “von Hanzemann cells” stain with?
Von Kossa, PAS, Perls, Giemsa
Von Hanzemann cells stain CD68, lysozyme, alpha-1-antitrypsin
What are von Hansemann cells vs. Michaelis-Gutmann bodies?
von Hansemann cells are large macrophages w/ eosinophilic cytoplasm and Michaelis-Gutmann bodies: round, laminated, calcified basophilic intracytoplasmic inclusions; comprised of incompletely killed bacteria within calcified phagolysosomes
Tularemia microbiology?
Gram-negative coccobacillus
Tx for Tularemia (Francisella tularensis)?
Streptomycin
H. influenza microbiology?
Gram-negative coccobacillus
What is Rhinoscleroma?
Chronic granulomatous infection of nose and upper respiratory tract
Microbiology of Rhinoscleroma?
Gram-negative rod, non-motile
Mikulicz cells?
Seen in Rhinoscleroma that is caused by klebsiella = macrophages with phagocytose bacteria
Phases of Rhinoscleroma?
Three clinical phases:
○Catarrhal phase - rhinitis, obstruction from soft tissue edema
○Granulomatous/infiltrative phase - granulomatous nodules in upper respiratory tract, epistaxis, dysphonia, anesthesia of soft palate, and Hebra nose
○Sclerotic phase - extensive scarring requires tracheotomy and nasal reconstruction
Hx of Rhinoscleroma?
Dense pan-dermal infiltrate of Mikulicz cells containing bacteria (seen w/ Warthin-Starry, Giemsa) and Russell bodies
Rat-bite fever (“Haverhill fever”) is caused by?
Streptobacillus moniliformis
Classic triad of rat bite fever?
Paroxysmal fever, migratory polyarthritis,
and acral rash
Gram-negative bipolar bacillus?
Yersinia pestis –> Plague shows characteristic “safety pin” appearance of bacteria on gram or giemsa stain
Most commonly affects men >40 years old who have predisposing factors: liver disease (hemochromatosis, cirrhosis, or alcoholism), diabetes?
Vibrio vulnificus from shellfish
Vibrio vulnificus px with?
Hemorrhagic bullae; Tx: doxycycline
Organisms from dog bites?
Pasteurella multocida, Pasteurella canis, or Capnocytophaga canimorsus
Organism from cat bites?
P. multocida
Organisms from human bites?
Eikenella corrodens (a/w chronic
infections), S. aureus (a/w severe infections), Peptostreptococcus, Enterococcus, and Bacteroides
Features of second stage of Lyme disease “Early disseminated”?
Early disseminated stage is a result of hematogenous spread of spirochetes if initial phase untreated
♦Borrelial lymphocytoma strongly a/w B. afzelii* and B. garinii* p/w firm, plum-colored tender nodule on earlobes (children), or nipple/areola (adults)
♦Arthritis (60%): monoarticular (knee)
♦Neurologic abnormalities (10%): Bell’s palsy
♦Cardiac complications (5%): AV block, myopericarditis
Features of third stage of Lyme disease “Chronic”?
♦Acrodermatitis chronica atrophicans strongly a/w B. afzelii* and B. garinii* occurs months to years after initial infection in middle-aged women; two clinical phases: erythematous plaques with “doughy”/ swollen skin on distal extremities (early phase; easily treated/reversible) n progresses to atrophic “cigarette-paper” skin w/ telangiectasias and subcutaneous fibrous nodules overlying joints
♦Other: encephalopathy, neuropathy, and chronic arthritis
What are the non-venereal treponematoses?
Yaws, pinta, and endemic syphilis (bejel)
All caused by Treponema pallidum subspecies
Yaws is caused by?
T. pallidum pertenue
Yaws is characterized by how many stages?
1° stage: indurated, red, painless papules that enlarges to 1–5 cm, then ulcerates (“Mother Yaw”); occurs at site of inoculation; lower extremities most common
2° stage: multiple, smaller, symmetrical, widespread eruption w/ “daughter yaws” face and intertriginous most common; hyperkeratotic plaques on soles (“crab yaws”); osteoperiostitis, polydactylitis, periosteal thickening
3° stage: necrotic and ulcerative abscesses that heal with severe/deforming scars; palmoplantar keratoderma; bony damage
“Skin + bone disease” “Yaws = Jaws”
Pinta is caused by?
T. pallidum carateum
Pinta stages?
1° stage: legs w/ papules surrounded
by red halo; enlarges to 10 cm plaques
2° stage: smaller scaly papules and psoriasiform plaques erupt (“pintids”) and change in color from red to blue to brown
to gray/black
3° stage: symmetric vitiligo-like lesions over bony prominences w/ atrophic epidermis; palmoplantar hyperkeratosis;
Endemic syphilis/“bejel” is caused by?
T. pallidum endemicum (mucosal disease “ENDemic syphilis attacks ENside surfaces”)
Early congenital syphillis features <2 years old?
Snuffles, perioral fissures, dactylitis, Parrot’s pseudoparalysis, syphilitic pneumonitis, epiphysitis, marasmic syphilis, pemphigus syphiliticus, and hepatitis
Late congenital syphillis features >2 years old?
Keratitis, mulberry molars, Hutchinson’s teeth (notched/peg-shaped incisors), rhagades (linear scars at angles of mouth), saddle nose, Higoumenakis syndrome, Clutton’s joints, optic atrophy, corneal opacities, and eighth nerve deafness
Treponemal and non-treponemal serologic studies?
Treponemal - FTA-ABS, MHA-TP, FTA-ABS-19S-IgM, SPHA
Non-treponemal - RPR, VDRL; IgG/IgM to cardiolipin
First serologic test to become positive in syphilis?
RPR and VDRL
What stains spirochetes?
Warthin-Starry stain
What “bodies” are seen in chlamydia?
“Gamma-Favre bodies” in macrophages on Giemsa stain
What “bodies” are seen in Granuloma inguinale?
“Safety pin” Donovan bodies on Wright or Giemsa stain of smears.
Granuloma inguinale is caused by intracellular Gram-negative bacillus
What is TB verruca cutis?
Reinfection via inoculation, in patients w/ previous infection w/ moderate to high immunity; #1 form of cutaneous TB; warty/verrucous, growing papule may heal over years
Hematogenous dissemination from lung, most often in immunosuppressed patients; pinpoint blue-red crusty papules n small scars
Acute miliary TB
Hansen’s disease = ?
Leprosy
Microbiology of leprosy?
Obligate intracellular, weakly acid-fast bacillus that parasitizes macrophages and Schwann cells
Leprosy cultures on?
Cannot be cultured in vitro n must be cultivated in mouse footpads or in armadillos
What is the Ridley-Jopling scale?
Divides leprosy into two polar forms (Lepromatous/LL [Th2 response] and Tuberculoid/ TT [Th1 response]), and three borderline forms (BL, BB, and BT)
Severe necrotizing vasculitis w/ thrombosis in patients from Mexico and South America with diffuse lepromatous leprosy is called?
Lucio phenomenon
Names of the 2 reactions states in leprosy?
Type 1 (reversal reaction; Th1) and Type 2 (erythema nodosum leprosum; Th2)
Ulceration of existing leprosy lesions and preferential targeting of nerves is called?
A type 1 reversal reaction, Th1, cell-mediated reaction (in BL).
Tx: Prednisone
Multisystem vasculitis and EN-like lesions scattered at previously unaffected leprosy skin sites is called?
Type 2, erythema nodosum leprosum reaction, highest risk with BL and LL patients receiving antimicrobial therapy; treatment = thalidomide
Leprosy type that has a grenz zone?
Lepromatous leprosy LL
Culturing M. marinum?
M. marinum grows best at 31°C (3 weeks required for growth), as opposed to the usual 37°C for most other mycobacteria
Rapid growing mycobacteria?
Mycobacterium fortuitum, chelonae, and abscessus
Nonfluorescent dermatophytes?
T. mentagrophytes, T. rubrum, M. nanum, T. megninii, T. gypseum, and T. verrucosum
Favus?
T. schoenleinii
Kerion caused by?
M. canis, T. verrucosum, T. mentagrophytes, and T. tonsurans
Majocchi granuloma and Tinea corporis caused by?
T. rubrum
What causes Tinea barbae?
T. verrucosum, T. mentagrophytes,
T. tonsurans, and T. rubrum
Tinea cruris caused by?
T. rubrum, E. floccosum, and
T. interdigitale
What causes vesiculobullous tines pedis?
T. mentagrophytes
What causes black piedra?
Piedra hortae
What causes white piedra?
Trichosporon asahii (most strongly linked to white piedra; may cause disseminated disease in immunocompromised patients), T. ovoides, T. inkin, and T. cutaneum
Tinea nigra is caused by?
Hortaea werneckii
Sporotrichoid spread mnemonic?
“No SALT”
Nocardia, Sporotrichosis, Atypical mycobacteria, Leishmaniasis, Tularemia
Cigar-shaped budding yeast?
Sporotrichosis from soil; Tx of choice: Itraconazole
“pop bead” or “chain of coins” appearance seen in?
Lobomycosis with species: Lacazia (Loboa loboi)
Px of Lobomycosis?
Keloid-like verrucous fibrotic nodules that can ulcerate; ear helix #1 site; men>women
Actinomycetoma different grain colors?
white grains > N. asteroides
red grains > A. pelletieri
yellow grains > Streptomycin somaliensis
Actinomycetoma tx?
Streptomycin/amikacin 1 TMP-SMX
Eumycetoma tx?
Surgical debridement
Fonsecaea pedrosoi causes?
Chromoblastomycosis
Pseudoepitheliomatous hyperplasia (PEH), granulomatous dermal inammation with medlar bodies (pigmented muriform cells, “copper pennies”) is seen in?
Fonsecaea pedrosoi
Diseases with parasitized macrophages?
tuberculoid granuloma with
intracellular 2 to 4 mm yeast in histiocytes (looks like leishmaniasis, but see yeast have surrounding halo and are more evenly distributed throughout histiocyte cytoplasm; lacks “marquee sign” and kinetoplast seen in?
Histoplasmosis; geographically: Ohio and Mississippi River valley from inhaled bird and bat droppings
Granulomatous dermal inflammation
with unipolar budding yeast (8–18 mm) (broad-based
buds
Blastomycosis; Geography: Eastern USA, Great Lakes, Ohio, and Mississippi River valleys
Coccidioidomycosis geography?
Desert Southwest United States (esp. Central Valley/San Joaquin Valley, California), Mexico, and Central America
VS. Paracoccidioidomycosis which is SOUTH America and Mexico
Microscopy of coccidioidomycosis?
Large (up to 100 mm) spherules
containing endospores; also has PEH and granulomatous inflammation
Px of Coccidioidomycosis?
Face #1 site; verrucous nodules or papules (can be molluscum-like), pustules, abscesses, or ulcerative lesions but Pulmonary manifestations are most common presentation
Microscopy: PEH, granulomatous dermal inflammation w/ multipolar budding yeast, mariner’s wheel or Mickey Mouse?
Paracoccidioidomycosis
Paracoccidioidomycosis px?
Granulomatous ulcerative oropharyngeal and perioral involvement in 70% of adults; cutaneous lesions can be contiguous, hematogenous, or via inoculation; clinical appearance of ulcers with infiltrated borders (verrucous) and hemorrhagic dots, and associated LAD (can be massive)
Candida species in chronic paronychia?
C. parapsilosis
Candida species with fluconazole resistance?
C. glabrata and C. krusei
Candida species with oropharyngeal candidiasis in HIV patients?
C. dubliniensis
Candida microscopy?
KOH = yeast and pseudohyphae
What allows candida to adhere to mucosal surfaces?
Chitin, mannoprotein, and glucan
“Median rhomboid glossitis” caused by mucocutaneous candida
“erosio interdigitalis blastomycetica” caused by candida usually affects third web space of fingers; also fourth web space of toes
Microscopy: single-celled sphere with a double cell wall and thick capsule (“halo” appearance), may have one or more buds (blastoconidia); collections of organisms look like soap bubbles is?
Cryptococcosis; C. neoformans and C. gattii
Stains for cryptococcosis?
India ink, PAS, mucicarmine, GMS, and Fontana-Masson
Virulence factor for cryptococcosis?
Glucuronoxylomannan polysaccharide capsule
Septate hyphae with 45° angle
branching?
Aspergillosis and Fusarium
Most common species of Aspergillosis?
Aspergillus fumigatus most common
A. flavus second most common
A. niger causes otomycosis
Most common fungus cultured in burn patients?
Fusarium solani
What can be acquired by inhalation or possibly abrasions with bamboo rat exposure as a risk factor?
Penicilliosis
* Species: P. marneffei is only pathogenic species
* Geography: Southeast Asia
Penicilliosis lesions?
Papules with central necrosis and molluscum-like lesions; face, arms, and
trunk
Broad ribbon-like nonseptate hyphae with 90° angle branching?
Zygomycosis i.e. mucormycosis
Phaeohyphomycosis is due to?
Dematiaceous (pigmented) fungi: Exophiala jeanselmei
Hyphae are pigmented/brown, and stain positive with Fontana-Masson?
Phaeohyphomycosis
Introduced into skin via trauma in contaminated water. Microscopy shows organisms with a morula-like appearance on H&E is?
Protothecosis
* Species: Prototheca wickerhamii, not a fungus but an algae. Px: olecranon bursitis
Very large, up to 300 mm sporangia
containing trophozoites in dermis, is most likely?
Rhinosporidiosis
Rhinosporidiosis px with slow-growing friable, red-purple, soft, lobulated, mucosal polyps, particularly on nose (associated with epistaxis), and conjunctivae in young men
Dermatobia hominis, human botfly causes?
Myiasis
Vector for leishmaniasis?
Sandflies, Phlebotomus (old world) or Lutzomyia (new world)
New World leishmaniasis?
L. mexicana, L. amazonensis, L. braziliensis (mucocutaneous)
Most common agent in diffuse cutaneous leishmaniasis, usually in immunocompromised?
L. amazonensis (Americas), L. aethiopica (Africa)
What is kala-azar?
Visceral leishmaniasis, old > new world most commonly L. donovani (India, Sudan, Bangladesh; most common cause in adults), L. infantum (Europe; often a/w HIV), L. chagasi
Kala-azar or black fever will present with?
Specific: papules, ulcers at bite site
Non-specific: purpura, hyperpigmentation (“black fever”), kwashiorkor changes (brittle hair
w/ discoloration), purpura
Leishmaniasis culture?
Novy-McNeal-Nicolle medium
PCR is most sensitive and specific test
Lesions arising up to 20 years after presumed recovery from untreated visceral leishmaniasis as nodules, verrucous papules, or hypopigmented macules, is?
Post-kala-azar dermal leishmaniasis
“Marquee sign” = amastigotes with kinetoplasts are arrayed around periphery of parasitized histiocyte cytoplasm
Leishmaniasis tx?
■ Cutaneous and mucocutaneous leishmaniasis: pentavalent antimony (e.g., sodium stibogluconate), miltefosine, pentamidine, intralesional 0.2% ciprofloxacin 1 long-pulsed Nd:YAG
■ Visceral leishmaniasis: amphotericin B (ToC)
Trypanosomiasis is caused by?
T. brucei gambiense - West Africa
T. brucei rhodesiense - East Africa
Vector: tsetse fly (Glossina)
What is trypanids?
Erythematous, urticarial or macular diffuse eruptions [6–8 weeks] seen in Trypanosomiasis
Trypanosomiasis tx?
Suramin or pentamidine if early Melarsoprol (E. African) or eflornithine (W. African) if CNS involvement
Ancylostoma braziliense cause?
Cutaneous larva migrans
Strongyloides stercoralis causes?
Larva current, moves 5–10 cm/hr, (cutaneous larva migraines moves slower 1-3cm/hr
Loeffler’s syndrome is?
= chronic strongyloidiasis which affects
lungs and GI tract and eosinophilia
Simulium fly, leopard skin, onchocercomas, causes?
Onchocerciasis (“River blindness”)
In Onchocerciasis, “River blindness”, if given diethylcarbamazine and an itchy eruption develops shortly after giving med in infected patient, is called?
Mazzotti reaction
Visible worms in adult eyes is called?
Loiasis
Chronic—granulomatous reaction in lymphatics causing lymphedema, elephantiasis, hydrocele causes?
Filariasis
Edwardsiella lineata (sea anemone) and Linuche unguiculata (thimble jellyfish cause?
Seabather’s eruption
Schistosoma, during the cercarial stage (snails are a vector) cause?
Swimmer’s itch, “cercarial dermatitis”
Primary dermatologic manifestation is periorbital edema (as a result of type I allergic reaction) and petechiae during parasite migration (esp. splinter hemorrhages) with peripheral eosinophilia and IgE are clues; muscle biopsy is diagnostic are indicative of?
Trichinosis
What can you get by eating raw sushi?
Gnathosomiasis
Gnathosomiasis px as?
GI symptoms + fever early on;
nodular migratory panniculitis
Free-living amoeba that can cause chronic ulcers?
Acanthomoeba
Free-living amoeba that can cause painless, red, and granulomatous plaque on central face?
Balamuthia
Free-living amoeba that can cause fulminate, fatal acute necrotizing meningoencephalitis?
Naegleria
GI-associated amoeba causing amebic colitis, +/- liver, lung involvement?
Entamoeba histolytica
Toxin in Fire ants?
Solenopsin D (piperidine alkaloid)
Bed bugs?
Cimex lectularius
Exaggerated bite reactions occur with?
CLL, chronic EBV
Immune reaction substance in bed bugs?
Nitrophorin
B. henselae causes?
B. quintana causes?
B. henselae -> cat scratch disease, bacillary angiomatosis
B. quintana -> bacillary angiomatosis
Train-track appearance of urticaria or hemorrhage and ophthalmia nodosa are seen in?
Lepidopterism (caterpillar dermatitis) due to direct contact with hairs and toxin-mediated reactions
