Derm Flashcards
what is hyperkeratosis
increase in stratum corneum / increased keratin
what is parakeratosis
nuclei in stratum corneum
what is acanthosis
thickened (increase) in stratum spinosum > darkening of skin
what is acantholysis
decreased cohesions between keratinocytes
what is spongiosis
intracellular odema
what is lentiginous
linear pattern of melanocyte proliferation within pidermal basal cell layer
explain general prsentation of psoriasis
well demarcated red scaly plaques
explain chronic plaque psoriasis
salmon pink plaques with silver scales
affect extensor aspects of knees, elbows, scalp
what occurs if you rub psoriasis
rubbing causes pin-point bleeding (Auspitz’ sign)
WHat is Koebner phenomenon
lesions form at site of trauma
what are histological features of psoriasis
parakeratosis, loss of granular layer, clubbing of rete ridges giving test tubes in a rack appearance
what does guttate psoriasis occur after
after group A strep throat
explain nail changes in psoriasis
POSH
Pitting
Onycholysis
Subungal hyperkeeratosis
explain presentationo of LIchen planus
Pruritic Purple Polygonal Papules Plaques
with
- mother of pearl sheen
- fine white network on surface called Wickam’s striae
where does lichen planus occur
on inner wrists OR oral mucous membrane
what does erythema multiforme occur in response to
Viral: HSV, mycoplasma
Drugs: SNAPP (Sulphonamide, NSAID, Allopurinol, Penicillin, Phenytoin)
what are seborrhoeic keratoses
rough plaques, waxy, stuck on
in middle aged/elderly
what are. actinic solar /senile keratoses
rough sandpaper like scaly lesions on sun exposed areas
what is a keratoacanthoma
rapidly growing dome shaped nodule
develops a necrotic, crusted centre
grows over 2-3 weeks tgen clears
what does bowens disease look like
flat, red scaly patches on sun exposed areas
how is the basement membrane in bowrens
INTACT - non invading the dermis
what is Bowens disease
intra-epidermal squamous cell carcinoma in situy
when does epithelial SCC occur
when Bowens invades the BM, speading to dermis
describe a BCC
RODENT ULCER
Rolled pearly edge, telangectasis, with central ulcer
what is the msot important prognostic factor for melanoma
Breslow thickness
what are the four subtypes of melanoma and when do they occur
- superficial preading: irregular bordr with variation in colour
- nodular: spreads deep
- acral lentigionous: on palms and soles of afro-carribeans
. lentigo maligna: on sun exposed area of elderly caucasian, flat and slow growing
What does SJS > TEN occur due to
drugs e.g. sulphonamides, anticonvulsants
how are SJS and TEN different
amount of skin detachment
<10% body surface on SJS
>30% body surface in TEN
what sign occurs in SJS/TEN
Nikolsky positive
