skin disorders Flashcards
melanosomes in blacks
present throughout the epidermal layers, unlike whites where melanosomes are mainly located on S. basale
Rubeola (measles)
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
Rubella (german measles or 3 day measles)
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
polyarthritis in adults
rubella and parvovirus
roseola infantum (6th disease)
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
Patient with chickenpox or varicella is infectious
week before rash, week after rash until vesicles become crusted
complications: Reye syndrome, cerebellitis, adult pneumonia, encephalitis, hepatitis
hidradenitis suppurativa (caused by S. aureus)
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
Rx for impetigo
Mupirocin ointment+dicloxacillin
erysipelas
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
tuberculoid type of leprosy
granuloma, intact cellular immunity, +lepromin skin test
digital autoamputation, hypopigmented skin
treat with dapsone and rifampin
lepromatous type of leprosy
organisms present, impaired cellular immunity, -lepromin test, no granulomas
leonine facies: nodular lesions on face
treat with dapsone+rifampin+clofazimine
most common fungal infections in decreasing order
tinea (worm) pedis–> tinea unguim (nail)–> tinea versicolor (color variations)–> tinea cruris (groin)
wood’s lamp and KOH-treated skin scrappings
UVA detects flurescent metabolites produced by organisms. it identifies yeasts and hyphae in S corneum or hair shafts
Trichophyton tonsurans
common cause of scalp infection in blacks
-wood’s lamp
Microsporum canis/audouinii
most common causes of scalp infection in whites
+wood’s lamp
tinea capitis
treat with oral terbinafine
topical imidazoles don’t work
trichophyton rubrum
is most common cause of all other tineas except versicolor
tinea versicolor
hypopigmentation= decrease in melanin synthesis
hyperpigmentation= enlargement of melanosomes
caused by malassezia furfur
spaghetti (hyphae) and meatballs (yeast)
treat with oral ketoconazole
intertrigo by candida albicans
erythematous rash in body folds
solar lentigo
liver spots, common in elderly
increased number of melanocytes
freckles have increased melanosomes and not melanocytes
types of malignant melanoma
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
keratoacanthoma
crateriform tumor with central keratin plug
looks similar to basal cell carcinoma. however, appears rapidly and spontaneously resolves with scarring
fibroepithelia tag
fleshcolored tag of skin with a stalk
common in elderly
Ichthyosis vulgaris
most common inherited skin disorder
AD
increased stratum corneum
absent stratum granulosum
hyperkeratotic dry skin on palms, soles and extensor areas
xerosis
most common cause of dry skin in elderly
decrease in skin lipids
Atopic dermatitis
type I IgE mediated hypersensitivity
Lupus skin involvement
DNA-anti-DNA Ab complexes deposit along basement membrane–> degeneration of basement membrane and hair shaft–> alopecia
Treat with anti-malarial drugs
Pityriasis rosea
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
erythema multiforme
triggered by infection
mycoplasma, HSV, drugs
rash has targetoid appearance
palmar involvement
erythema nodosum
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
granuloma annulare is associated with
DM
pyoderma gangrenosum
ulcerative cutaneous disease associated with systemic disease like UC/Crohn, RA, MPD
Due to dysregulation of immune system
