091914 infections

Question 1

impetigo

Answer 1

common superficial bacterial infection
most common in kids
highly infectious (direct contact)
Staph aureus (less commonly Strep pyogenes)
small vesicles that burst, replaced by thick yellowsih crust that is honey colored

mouth, nose, extremities

Question 2

bullous impetigo

Answer 2

blisters because the connections btwn keratinocytes are destroyed

Question 3

histology of impetigo

Answer 3

crust right at stratum corneum-will see serum and neutrophils

Question 4

staphlylococcal scalded skin syndrome

Answer 4

infant and children
toxin mediated type of exfoliative dermatitis
toxigenic strains of Staph aureus
two exotoxins (epidermolytic toxin A and epidermolytic toxin B)

causes intraepidermal splitting through granular layer. large, flaccid bullae

Question 5

SSSS occurs where

Answer 5

face
neck
trunk (includes axillae and groins)

Question 6

what is important to remember about where SSSS doesn’t involve?

Answer 6

doesn’t involve mucous membranes

Question 7

difference btwn kids and adults in terms of SSSS?

Answer 7

in adults, a septicemia may ensue

Question 8

cellulitis

Answer 8

deep pyogenic infection
diffuse inflam of connective tissue of skin and, or the deeper soft tissues/fat
expanding area of erythema

beta hemolytic strep, coagulase positive staph, other organisms

Question 9

where is cellulitis more common

Answer 9

legs

Question 10

erysipelas

Answer 10

distinctive type of cellulitis-upper dermis
bacterial skin infection involving upper dermis (superficial cutaneous lympathics)

prevalent in elderly

s pyogenes is most common causative agent

Question 11

what does erysipelas look like clinically

Answer 11

sharply outlined
edema
erythematous
tender
painful plaque

Question 12

histology of erysipelas

Answer 12

lot of white space due to fluid in dermis

increased amt of neutrophils

Question 13

verrucae

Answer 13

warts
HPV (most caused by low risk HPV)
verruca vulgaris (anywhere, commonly on hands), plantar warts, anogenital warts

regress spontaneously

Question 14

histology of verrucae

Answer 14

papillomatous, hyperplasia of epidermis. filiform
prominent granular cell layer (has enlarged clumps of irregular basophilic keratohyaline granules)

large cells with prominent vacuolated cytoplasm(koilocytosis) and small nucleus are seen in upper layers of epidermis

Question 15

condyloma accuminatum

Answer 15

wart on genital areas
caused by HPV 6 and 11
cauliflower lesions with stalk

Question 16

acanthosis

Answer 16

diffuse epidermial hyperplasia

Question 17

HSV lesions look like

Answer 17

clear vesicles, heal w/o scar

Question 18

what lesions are usually seen with varicella?

Answer 18

lesions develop in successive crops, so rash usually has pocks at different stages of development (papules, vesicles, pustules, crusted lesions, healing lesions)

Question 19

herpes zoster presents usually in what regions of the body

Answer 19

thoracic or lumbar, or facial

Question 20

histophatology of herpes zoster vs herpes simplex

Answer 20

virtually indistinguishable

Question 21

how does varicella spread

Answer 21

respiratory

Question 22

histopathology of HSV

Answer 22

epidermal acantholysis

several multinucleated keratinocytes with glassy intranuclear inclusions (Cowdry type A) and ballooning degeneration

Question 23

tzank smear

Answer 23

fast cytological diagnosis
make a smear from the base of a freshly opened vesicle and stain it with Giemsa stain

not as sensitive
for testing to see if it’s herpes

Question 24

moluscum contagiosum

Answer 24

cuteaneous infection
caused by brick shaped DNA poxvirus
transmitted by direct skin contact btwn children

solitary or multiple dome shaped, UMBILICATED, waxy papules

in adults, can be sign of sexual transmission or immunosuppression

Question 25

histoly of molluscum contagiosum

Answer 25

inverted lobules of acanthotic and hyperplastic epidermis

eosinophilic inclusion bodies in the cytoplasm of keraticnocytes just above basal lyaer (Henderson Patterson or molluscum bodies)

Question 26

scabies

Answer 26

caused by mite Sarcoptes scabiei
acquired through close contact
hands and feet, penis
extremely pruritic
papulovesicular

Question 27

histology of scabies

Answer 27

eggs in burrows in epidermis-stratum corneum

Question 28

dermatophytoses

Answer 28

group of related fungi
invade keratinized tissues
cause ringworm/tinea

epidermophyton, microsporum, trichophyton

clinical appearances are quite variable-scaly erythematous plaques, often annular

Question 29

epidermophyton invades what

Answer 29

epidermal keratin

Question 30

microsporum and trichophyton invade what?

Answer 30

epidermal keratin and also hair

Question 31

tinea capitis

Answer 31

scaly patches on scalp

Question 32

tinea corporis

Answer 32

scaly, annular, erythematous patches on body

Question 33

tinea manuum and pedis

Answer 33

erythema and scale of hands or feet

Question 34

tinea cruris

Answer 34

erythematous, macerated patches of groin

Question 35

tinea unguium (onchomycosis)

Answer 35

thickened yellow nails

Question 36

histology of dermatophyte infec

Answer 36

wide range of changes, including:
presence of neutrophils
sandwich sign (hyphae in btwn normal stratum corneum and lower layer of stratum ocrneum with either orthokeratotic or parakeratosis)

PAS stain can reveal fungus

Question 37

KOH prep rapid test

Answer 37

can find branching hyphae of fungal infec

Question 38

tinea versicolor

Answer 38

worldwide but more common in tropical climates

majority caused by yeast Malassezia globosa

clinical pres: multiple irregular areas of hypo or hyperpigmentation, which are circular and macular, may become confluent

Question 39

histology of tinea versicolor

Answer 39

stratum cornuem has round budding yeasts and short septated hyphae–sphagetti and meatballs. clearly seen in H & E