skin disorders

Question 1

melanosomes in blacks

Answer 1

present throughout the epidermal layers, unlike whites where melanosomes are mainly located on S. basale

Question 2

Rubeola (measles)

Answer 2

RNA paramyxovirus

prodrome: Cough, Coryza (runny nose), conjunctivitis–> 3C’s

Koplik spots on buccal mucosa

rash after koplik spots: CD8 damage endothelial cell containing virus, begins at head then to trunk and extremities, they can become confluent

complications: giant cell pneumonia, acute appendicitis, otitis media, encephalitis

not teratogenic

Question 3

Rubella (german measles or 3 day measles)

Answer 3

RNA togavirus

dusky red spots (Forchheimer spots) on posterior soft/hard palate, develop at beginning of rash

maculopapular rash with discrete lesions, not confluent that last for 3 days

painful postauricular lymphadenopathy

teratogenic

Question 4

polyarthritis in adults

Answer 4

rubella and parvovirus

Question 5

roseola infantum (6th disease)

Answer 5

HHV-6

most common viral exanthum in children<2

red macules on soft palate 48 hours before rash

macupapular rash occurs abruptly after 3-7 days of high fever–> febrile seizure

Question 6

Patient with chickenpox or varicella is infectious

Answer 6

week before rash, week after rash until vesicles become crusted

complications: Reye syndrome, cerebellitis, adult pneumonia, encephalitis, hepatitis

Question 7

hidradenitis suppurativa (caused by S. aureus)

Answer 7

chronic infection

swollen, painful, inflamed apocrine glands usually in axilla or groin

can involve adjacent subcutaneous tissue and fascia

hallmark is presence of sinus tracts

must aspirate and culture pus

difficult to treat

Question 8

Rx for impetigo

Answer 8

Mupirocin ointment+dicloxacillin

Question 9

erysipelas

Answer 9

cellulitis with raised borders

common on face and lower extremities

treat with PCN G if on extremities,vanco if on face

caused by S. pyogenes

Question 10

tuberculoid type of leprosy

Answer 10

granuloma, intact cellular immunity, +lepromin skin test

digital autoamputation, hypopigmented skin

treat with dapsone and rifampin

Question 11

lepromatous type of leprosy

Answer 11

organisms present, impaired cellular immunity, -lepromin test, no granulomas

leonine facies: nodular lesions on face

treat with dapsone+rifampin+clofazimine

Question 12

most common fungal infections in decreasing order

Answer 12

tinea (worm) pedis–> tinea unguim (nail)–> tinea versicolor (color variations)–> tinea cruris (groin)

Question 13

wood’s lamp and KOH-treated skin scrappings

Answer 13

UVA detects flurescent metabolites produced by organisms. it identifies yeasts and hyphae in S corneum or hair shafts

Question 14

Trichophyton tonsurans

Answer 14

common cause of scalp infection in blacks

-wood’s lamp

Question 15

Microsporum canis/audouinii

Answer 15

most common causes of scalp infection in whites

+wood’s lamp

Question 16

tinea capitis

Answer 16

treat with oral terbinafine

topical imidazoles don’t work

Question 17

trichophyton rubrum

Answer 17

is most common cause of all other tineas except versicolor

Question 18

tinea versicolor

Answer 18

hypopigmentation= decrease in melanin synthesis

hyperpigmentation= enlargement of melanosomes

caused by malassezia furfur

spaghetti (hyphae) and meatballs (yeast)

treat with oral ketoconazole

Question 19

intertrigo by candida albicans

Answer 19

erythematous rash in body folds

Question 20

solar lentigo

Answer 20

liver spots, common in elderly

increased number of melanocytes

freckles have increased melanosomes and not melanocytes

Question 21

types of malignant melanoma

Answer 21

superficial= most common, lower extremities, arm and upper back

lentigo maligna melanoma=common in elderly, extension of intraepidermal lesions into dermis, on part of face most exposed to sun, least likely to have vertical phase

nodular phase= vertical phase only

acral lentiginous melanoma

Question 22

keratoacanthoma

Answer 22

crateriform tumor with central keratin plug

looks similar to basal cell carcinoma. however, appears rapidly and spontaneously resolves with scarring

Question 23

fibroepithelia tag

Answer 23

fleshcolored tag of skin with a stalk

common in elderly

Question 24

Ichthyosis vulgaris

Answer 24

most common inherited skin disorder

AD

increased stratum corneum

absent stratum granulosum

hyperkeratotic dry skin on palms, soles and extensor areas

Question 25

xerosis

Answer 25

most common cause of dry skin in elderly

decrease in skin lipids

Question 26

Atopic dermatitis

Answer 26

type I IgE mediated hypersensitivity

Question 27

Lupus skin involvement

Answer 27

DNA-anti-DNA Ab complexes deposit along basement membrane–> degeneration of basement membrane and hair shaft–> alopecia

Treat with anti-malarial drugs

Question 28

Pityriasis rosea

Answer 28

initially present as a single large, oval, scaly, rose-colored plaque on trunk (herald patch)–> days or weeks later papular erruption on trunk–> rash follows the lines of cleavage–> christmas tree destribution

pruritic

remit spontaneously

Question 29

erythema multiforme

Answer 29

triggered by infection

mycoplasma, HSV, drugs

rash has targetoid appearance

palmar involvement

Question 30

erythema nodosum

Answer 30

inflammatory lesion of subcutaneous fat (panniculitis)

more common in women

raised, painful and red nodules on anterior shins

associated with coccidiomycoses, histoplasmosis, TB, leprosy, sarcoid, pregnancy, OCP

Question 31

granuloma annulare is associated with

Answer 31

DM

Question 32

pyoderma gangrenosum

Answer 32

ulcerative cutaneous disease associated with systemic disease like UC/Crohn, RA, MPD

Due to dysregulation of immune system