Vesiculobulous eruptions

Question 1

Herpes histology

Answer 1

Necrosis of all epidermal cell types
multinucleated keratinocytes
dermal inflammation

Question 2

Herpes clinical features

Answer 2

grouped vesicles on an erythematous base

Labialis usually HSV1, urogenital HSV2 but many overlap

Question 3

Herpes Dx

Answer 3

based on morphology
Tzank smear
viral culture
antibody testing
skin biopsy

Question 4

Varicella etiology

Answer 4

caused by Varicella-Zoster virus
Hematogenous spread (Christmas tree distribution)

Question 5

Varicella histology

Answer 5

necrosis of all epidermal cell types
multinucleated keratinocytes
dermal inflammation

Question 6

Varicella clinical features

Answer 6

“dewdrop on a rose petal”
initial lesions are papules which become vesicles
eventually crust over, may heal with scarring

Question 7

Herpes etiology

Answer 7

most adults have been exposed
virus persist in sensory ganglia
ppt by UV, menses, fever, URTI, immunodeficiency

Question 8

Varicella Dx

Answer 8

viral culture
Tzank smear
skin biopsy

Question 9

Herpes Zoster etiology

Answer 9

recurrent varicella-zoster virus

Question 10

Herpes zoster histology

Answer 10

necrosis of all epidermal cell types
multinucleated keratinocytes
dermal inflammation

Question 11

Herpes zoster clinical features

Answer 11

prodome of neuritic pain for days to weeks
acute vesicles, then crusted papules
distribution is unilateral and dermatomal
grouped vesicles on erythematous base

Question 12

Herpes zoster Dx

Answer 12

viral culture
Tzank smear
skin biopsy

Question 13

Nonbullous impetigo etiology

Answer 13

superficial infection of epidermis caused by GAS or staphy aureus

Question 14

Nonbullous impetigo histology

Answer 14

neutrophils gathering beneath stratum corneum

Question 15

Nonbullous impetigo clinical features

Answer 15

scalling
honey-crusted
non-bullous

Question 16

Nonbullous impetigo dx

Answer 16

gram stain and culture

biopsy usually not required for dx

Question 17

Bullous impetigo etiology

Answer 17

bacterial skin infection caused by staph aureus

Question 18

Bullous impetigo histology

Answer 18

neutrophils gathering beneath stratum corneum

Question 19

Bullous impetigo clinical features

Answer 19

vesicles and bullae
easily breakable
clear/slightly yellow fluid
shallow erosions form if bullae break

Question 20

Bullous impetigo dx

Answer 20

gram stain and culture

biopsy usually not required for dx

Question 21

Arthropod bites etiology

Answer 21

impossible to differentiate creature;
mites, ticks, spiders, centipedes, millipedes, mosquitos, black flies, sand flies, bedbugs, ants, bees, wasps, hornets, fleas

Question 22

Arthropod bites clinical features

Answer 22

grouped papules or vesicles
"breakfast-lunch-dinner" pattern
pruritic/urticarial papules
may be painful
often only one person in each group is bitten

Question 23

Bedbug etiology

Answer 23

red-brown, size of ladybug, not disease vectors
nocturnal
not confined to beds

Question 24

bedbug clinical features

Answer 24

erythematous papules, vesicle,s nodules

bites on body and head and neck