Infectious Derm II Flashcards
What are the three major variants of impetigo?
- Non-bullous
- Bullous
- Ecthyma
What are the top two causes of impetigo in order?
S. aureus
S. Pyogenes
What is the age range that is generally affected with impetigo?
2-5 years
What is the treatment for impetigo?
Topical abx
What is ecthyma? What does it look like?
- Ulcerative form of impetigo–lesions extend into the dermis
- Appear as punched out ulcers surrounded by raised margins, covered with yellow crust
punched out ulcers surrounded by raised margins, covered with yellow crust = ?
Ecthyma
Where on the body does ecthyma usually occur?
Distal extremities, with regional LAD present
What are the preventative measures for impetigo?
Good handwashing
What is the oral treatment for impetigo? Topical?
oral abx like dicloxacillin or cephalexin
Topical mupirocin
Hot tub folliculitis = ?
Pseudomonas
What is the usual infectious agent that cause folliculitis?
Staph aureus
What is the treatment for folliculitis?
cleanse 3x/day and oral anti staph
What is a furuncle?
Staph infection of an obstructed hair follicle
-Presents as a red, TTP, inflamed nodule that becomes fluctuant with central suppuration
What is the treatment for a furuncle?
I and D
What are carbuncles?
Coalesced furuncles–large abscesses that are usually of staph orign
What is the treatment for a carbuncle?
I and D, maybe oral abx
What is hidradenitis suppurativa?
Chronic suppurative infection of apocrine sweat glands, most often d/t staph
-Leads to recurrent abscesses
What is the treatment for hidradenitis suppurativa?
Moist compresses and I and D
What, generally, is cellulitis?
- Infection of the dermis that often begins at a wound.
- Presents as a spreading, red, nonfluctuant, TTP, plaque, that has a poorly defined border
Where on the body is cellulitis usually found?
Legs
What are the associated signs of cellulitis?
Lymph streaking
What is characteristics of cellulitis if caused by strep?
Bullous lesions may form
spreading, red, nonfluctuant, TTP, plaque, that has a poorly defined border = ?
Cellulitis
What are the risk factors for cellulitis?
Preexisting skin infection or trauma
What usually causes cellulitis?
Gram positive organisms
What is the causative agent of animal bite and human bite cellulitis?
Animal = pasteurella multocida Human = Eikenella Corrodens
What is the treatment for purulent vs nonpurulent cellulitis?
Purulent = treat for MRSA Non-purulent = GAS
What are the causes of HA-MRSA? (3)
- Abx use
- Surgical site infection
- ICU
What are the causes of CA-MRSA? (3)
- proximity to others with MRSA
- Skin trauma
- Shaving
What causes erysipelas, and where does it tend to occur?
GAS
Legs or face
What, generally, is erysipelas?
Superficial cellulitis with marked dermal lymphatic involvement
What are the systemic symptoms of erysipelas?
Fevers
Leukocytosis
HA
Emesis
What is the major difference between cellulitis and erysipelas?
Erysipelas is sharply demarcated, while cellulitis is not
What causes the rash with scarlet fever?
Strep exotoxin
Where does the rash begin with scarlet fever? How does it progress?
- Face
- Neck
- Upper chest
- Progresses downward
What are the oral findings of scarlet fever? (2)
- Strawberry tongue
- Perioral pallor
What are the palpable characteristics of the rash with scarlet fever?
Feels like sandpaper
What are the pastia’s lines that can be seen with scarlet fever?
a clinical sign in which pink or red lines formed of confluent petechiae are found in skin creases, particularly the crease in the antecubital fossa
Does the rash with scarlet fever blanch?
Yes
What areas are spared with scarlet fever?
Peri-oral area
Where is the rash accentuated with scarlet fever?
Antecubital areas
Axillary folds
What happens to the scarlet fever rash?
After 4 days, there is extensive desquamation of the skin
What is the treatment for scarlet fever?
PCN
What is Ritter’s disease?
SSSS
What causes SSSS?
Exfoliative exotoxin of staph aureus
What is SSSS called in neonates?
Pemphigus neonatorum
What is the progression of the rash with SSSS?
Within 24 hours, large clear bullae develop which gradually shed, leaving a red, denuded base
What causes toxic shock syndrome?
one or more exotoxins of staph aureus
What are the s/sx of toxic shock syndrome?
- n/v
- Hyperemia of the oral
- Kidney failure
- Hepatitis
True or false: bacteremia is not a feature of toxic shock syndrome
True
What is the treatment for toxic shock syndrome?
Abx, but more so aggressive supportive therapy
What part of the skin is affected with necrotizing fasciitis?
Fascia just above the muscle
What is the appearance of the skin with necrotizing fasciitis?
Rapidly expanding dusky, edematous, red plaques with blue discoloration.
Expanding dusky, edematous, red plaques with blue discoloration. = ?
Necrotizing fasciitis
What are the symptoms of nec fash?
Anesthesia of the skin
What is the treatment for nec fash?
WIdespread debridement and broad spectrum abx
What are types I - III of Necrotizing fasciitis?
Type I = poly microbial
Type II = GAS
Type III = Gas gangrene or Clostridial
What is Fournier’s gangrene?
Necrotizing fasciitis of the perineum and scrotum
What are the x-ray findings that may be present with Necrotizing fasciitis?
gas
What area of the body is particularly bad for Necrotizing fasciitis?
Abdomen
Over what age is a bad prognostic factor for Necrotizing fasciitis?
50
What diseases are bad prognostic signs for Necrotizing fasciitis? (2)
- Atherosclerosis
- DM
Which neisseria meningitidis strain is there no vaccine available for?
B
What is the rash that is seen with meningococcemia?
Erythematous macules, with brown stained appearance. Later lesions become purpuric with an irregular edge
True or false: the petechia with meningococcemia always spares the conjunctiva?
False-it can
What is the treatment for meningococcemia?
PCN
True or false: there is meningococcus in the rash with meningococcemia
True–don’t touch it
What are the three types of fungi, based on their location/source?
Geophilic
Zoophilic
Anthrophilic
What are the three major genera of fungi that infect humans?
- Epidermophyton
- Microsporum
- Trichophyton
What area of the body do dermatophytes infect? What allow them to infect this area?
- Keratinized tissue
- Have keratinase that allows them to live there
Yeasts are more likely to infect what parts of the body?
Deep skin or mucous membranes
What is the cause of tinea versicolor? What is the appearance with KOH prep?
Malassezia furfur
Spaghetti and meatballs
What is the causative agent of tinea pedis?
Trichophyton rubrum or mentagrophytes
What are the three major clinical patterns of tinea pedis? Which is most common?
- Interdigital
- Moccasin
- Vesiculobullous
What is the moccasin type of tinea associated with?
Onychomycosis
What are the findings of tinea manus?
Whiteness in the creases of the hand
What are the characteristics of the vesiculobullous type of tinea?
Grouped, 2-3 mm vesicles, often on the arch of the instep of the foot
What are the topical agents for tinea?
Azoles
Terbinafine
What is the best way to diagnose tinea?
KOH prep
What are the characteristics of tinea corporis?
Sharply marginated annular plaque with central clearing and scaling at the edges
Sharply marginated annular plaque with central clearing and scaling at the edges
Tinea corporis
Where in the lesion of tinea corporis is the fungi most active, and thus where you should take a sample from for dx?
Margins
What should always be assessed for with tinea corporis?
Tinea pedis
What is the usual fungi involved with tinea corporis?
Trichophyton rubrum
What are the usual fungi involved with tinea cruris? (2)
Epidermophyton floccosum
Trichophyton rubrum
What is the treatment for tinea corporis? When is systemic therapy indicated?
Topical antifungals
-systematic if poor response to topical, or large surface area
What are the two types of tinea on the face? How does each appear?
- Tinea faciei = corporis on the face
- Tinea barbae = multiple pustules around hair follicles
What is the fungus usually responsible for tinea barbae?
Trichophyton mentagrophytes
What is the usual presentation of tinea capitis?
Patch of alopecia with black dots, which are hairs that have broken off at the skin
What are the fungi that cause tinea capitis?
Microsporum canis, audouninii
Who usually gets tinea capitis?
School aged children
What is a kerion?
Pustules of the hair shaft with tinea capitis develop, forming an inflammatory nodule
What is the treatment for tinea capitis?
Topical agents not effective–oral griseofulvin
What is the treatment for onychomycosis?
Oral terbinafine x 12 weeks
What is the usual presentation of tinea versicolor?
Well demarcated hyper and hypopigmentation
What is the treatment for tinea versicolor?
Selenium shampoos, ketoconazole
What is the appearance of intertrigo?
Sharply defined red plaques involving skin folds with surrounding satellite macules
What is the usual cause of diaper dermatitis, and what does it look like?
- Beefy red plaques with white scales
- Candida
Is a diaper rash does not improve with barrier creams like Zn oxide, what pathogen should be suspected?
candida
What is the treatment for candidal diaper rashes?
Nystatin
Cradle cap in infants = ?
Seborrheic dermatitis
What causes seborrheic dermatitis?
Increased sebaceous gland activity causes an inflammatory reaction to malassezia species
What does seborrheic dermatitis look like?
Ranges from fine white scale to erythematous patches and plaques with greasy yellow scales
What is the fungal infection commonly seen with PD?
Seborrheic dermatitis
What is the treatment for seborrheic dermatitis?
Ketoconazole
What are the symptoms of candidal vulvovaginitis?
Creamy white d/c with pruritis
What is candidal paronychia? What is the risk that this presents?
Fungal infection of the nail folds
secondary infection with bacteria
What is the lepromatous form of TB?
Infiltrative cutaneous lesions will ill-defined borders
What is the tuberculoid leprosy?
Benign course, but with cutaneous lesions that are frequently erythematous with elevated border
What is the treatment for lepromatous and tuberculoid leprosy?
- lepromatous = Dapsone, RIPE
- tuberculoid = excise +systemic therapy
What is the parasite that causes pediculosis (lice)?
Pediculus humanus
Where is the most common place to find head lice on the head?
retroauricular and occipital scalp
What is the treatment for head lice?
Permethrin or malathion
What is the usual presentation of scabies?
Multiple erythematous papules on trunk, extremities, and genitals
Burrows are pathognomonic
What is the best way to diagnose scabies?
skin scrapings and microscopy
What is the treatment for scabies?
Oral ivermectin
What is Norwegian scabies?
Scabies + hyperkeratosis
What is pediculosis pubis? Treatment?
Pubic lice
Ivermectin
What is the usual presentation of bed bugs?
Clusters of Pruritic, erythematous and edematous papules
What is the parasite that causes bed bugs?
Cimex lectuularis
What is the treatment for bed bugs?
Topical steroids and antihistamines
Burn everything
What causes rocky mountain spotted fever? Presentation?
Rickettsia rickettsii
ILI + centipedal rash
What are the lab abnormalities that may be seen with RMSF?
Hyponatremia and thrombocytopenia
