Skin Infections

Question 1

morphology of varicella

Answer 1

vesicle, pustule with secondary morphology of crusting and erosion

acute viral illness secondary to primary exposure to human herpes virus 3

Question 2

how does varicella present?

Answer 2

fever, malaise and myalgia, then eruption begins on face and scalp within 24-48hr as crops of erythematous papules w/ central vesiculation

older lesions develop into pustules then crust to heal in 7-10 days

virus reamins in dormant in nerve ganglia for reactivation

Question 3

what results as a reactivation of dormant varicella?

Answer 3

herpes zoster

pattern of skin dermatomes

Question 4

what sequelae of varicella requires opthalmologic consult?

Answer 4

facial involvement of 1st branch of trigeminal nerve

evaluate for corneal involvement

Question 5

what is the morphology of HSV lesions?

Answer 5

grouped vesicles evolving into pustules

Question 6

Tx of HSV

Answer 6

antivirals PO

acyclovir, famciclovir, valacyclovir

Question 7

what is this a presentation of?

Answer 7

HSV on finger; appear deeper due to increased thickness of stratum corneum on palmar aspect of finger

Question 8

what is this a presentation of?

Answer 8

erythema multiforme (EM)

papules, vesicle

target lesions

precipitated by infection

minor and major; minor has no mucosal involvement

Question 9

what is the presentation of scabies?

Answer 9

pruitic dermatitis

caused by scabiel var. hominis

burrow sign (wavy, thread-like, grayish-white)

Question 10

what is the timeline of scabies infestation?

Answer 10

30-day life cycle of mites

incubation period before symptoms develop can range from days to months

2-6 weeks before sensitization

Question 11

Tx for scabies

Answer 11

two topical treatments 1 wk apart

applied overnight from head to toe

permethrin cream

for children under 2 and pregnant women, sulfur in petrolatum

Question 12

what precautions should you take in a household with scabies outbreak?

Answer 12

no need to treat pets

all family members and close contacts

Question 13

dx of head lice

Answer 13

presence of 0.8mm eggs (nits) attached to scalp hairs

Question 14

Tx for head lice

Answer 14

topical pediculoside

2 applications, 1 week apart

Question 15

what is this a presentation of?

Answer 15

malassezia furfur causing tinea versicolor

well demarcated brown scaling patches that cause temporary hypopigmentation

Question 16

morphology of thrush

Answer 16

primary: erosion
secondary: macerated white scale

Question 17

what is this a presentation of?

Answer 17

candida intertrigo

primary morphology: patch, pustules, papules

secondary morphology: erosions, scale

diaper rash is form of intertrigo (superinfected with candida)

Question 18

what is this a presentation of?

Answer 18

dermatophytoses

three genera: microsporum, trichophyton, epidermophyton

Question 19

what is the morphology for all forms of tinea?

Answer 19

primary: annular plaque, patch, vesicle
secondary: scale, fissure

Question 20

what is this a presentation of?

Answer 20

tinea pedis

Question 21

this pattern of thicken stratum corneum is called

Answer 21

moccasin pattern

Question 22

what is this a presentation of?

Answer 22

tinea cruris (jock itch)

Question 23

what is this a presentation of?

Answer 23

tinea unguis

Question 24

what is this a presentation of?

Answer 24

molluscum contagiosum

morphology: umbilicated papule, pearly, waxy papules

resolve spontaneously

Tx with curettage, manual expression, cryotherapy

Question 25

what is this a presentation of?

Answer 25

HPV wart papule, plaque, verrucous hyperkeratotic, exophytic, dome-shaped punctuate black dots (thrombosed capillaries)

Question 26

what is this a presentation of?

Answer 26

flat warts

Question 27

Tx for HPV warts

Answer 27

cryotherapy

Question 28

what is this a presentation of?

Answer 28

impetiginization excoriation of antecubital fossae honey colored, sticky crusts

Question 29

what is this a presentation of?

Answer 29

folliculitis pustule erythematous rim shaving exacerbates folliculitis

Question 30

what is this a presentation of?

Answer 30

furuncle/carbuncle (contiguous collection of boils) boils collection of pus walled off from surrounding tissues Tx with PO cephalosporin

Question 31

what is this a presentation of?

Answer 31

staphylococcal scalded skin syndrome patch, dcaling or desquamation is secondary morphology primarily disease of infants and young children flexual areas

Question 32

what is TTS caused by

Answer 32

S. aureus exotoxin sudden onset of high fever diffuse erythema, scarlatiniform exanthem Tx with beta-lactamase resistant Abx

Question 33

what is this a presentation of?

Answer 33

erysipelas superficial variant of cellulitis caused by strep 10-14 day penicillin

Question 34

what is this a presentation of?

Answer 34

cellulitis rubor (erythema) calor (warmth) dolor (pain) tumour (swelling)

Question 35

Tx for cellulitis

Answer 35

10-day course of Abx (cephalexin, clindamycin, dicloxacillin)

Question 36

what is this a presentation of?

Answer 36

necrotizing fasciitis rapidly progressive necrosis severe pain out of proportion ot skin findings does not respond to Abx