histo derm Flashcards
define hyperkeratosis
increase in keratin increase instratum corneum
what is parakeratosis
increase in nuclei of stratum corneaum
what is acanthosis
increase in stratum spinosusm
what is acantholysis
reduction in cohesions between keratinocytes
what is spongiosis
intercellular oedema
define lentiginous
linear pattern of increase in melaocyte proliferation within epidermal basal cell layer
histology of acute dermatitis
dilated dermal capiliiaries spongiosis inflammatory infiltrate into dermis
histology of chronic dermatitis
acanthosis crusting/ scaling
type of reaction for chronic dermatitis
type IV
what is the pathology of seborrhoeic dermatitis
allergic reaction toalassezia yeast affect face, eyebrow, ant chest, ear
histology of psoriasis
loss of granular cell layer munroes microabscesses “test tubes in a rack” clubbing of rete ridge parakeratosis
what is auspitz’s sign
psoriasis rubbling the lesion causes pinprick bleeding
what is koener phenomenon
psoriasis trauma causes a plaque to develop
nail changes in psoriasis
pitting onchylysis subungal hyperkeratosis
subtypes of psoriasis
guttate flextural plaque pustular
when does guttate psoriasis develop
in children 2 weeks after strep throat raindrop appearance
lichen planus lesion appearance
purple pruritic polygonal plaque papules mother of pearl sheen
what is wickham’s striae
white lacy overlying pattern on lichen planus papules
where does lichen planus occur
inner wrists and oral mucosa
histology of lichen planus
basal cell degeneraton saw toothing of rete ridges
appearance of erythema multiforme
annular target lesions on extensor surfaces
drugs causing erythema multiforme
Sulphonamides NSAIDS Allopurinol Phenytoin Penecillin
dermatitis herpetiformis pathology
IgA binds to basement membrane and forms subepidermal bullae
dermatitis herpetiformis presentation
itchy vesicles on extensor surfaces of elbows and buttocks
histologyo fdermatitis herpetiformis
microabscesses coalesce to form subepidermal bullae neutrophil and IgA are deposited at tip of dermal papillae
pemphigoid pathology
linear deposition of IgG which binds to hemidesmosomes on the the basememnt membrane
histology of pemphigoid
IgG deposition in a linear pattern along basement membrane subepidermal bullae with eosinophils
presentation of pemphigoid
large tense bullae on erythematous base often ofn forearms, axillae, groin of elderly patients
pathology of pemphigus
IgG antibodies bind to desmosomal proteins and form intrapidermal bullae
hisotlogy of pemphigus
intraepidermal bullae netlike deposition of intercellular IgG
sebhorroeic keratosis
rough plaques waxy middle aged pt
actinic keratosis histology
Solar elastosis Paraketaosis Atypia Inflammation Not full thickness
actinic keratosis presentation
rough sandpaper like scaly lesion on sun exposed area
presentation of keratoacanthoma
rapidlly growing dome shaped nodule with a necrotic crushed centre grows over 2-3 weeks and clears spontaneously
histology of keratoacanthoma
like SCC
bowen’s disease histology
full thickness dysplasia BM intact
presentation of bowen’s disease
intra epidermal squamous cell carcinoma in situ red flat and scaly on sun exposed areas
SCC
dysplasia nuclear crowding spead through BM into dermis
BCC appearance
pearly telangectasi palisading mass of basal cells pushing into dermis
types of malignant melanoma
lentigo maligna melanoma superfical spreading nodullar acral lentiginous
most important prognostic factor in malignant melanoma
breslow tihckness
histology of malignant melanoma
atypical melanocytes theat grow horizontally then vertically buckshot appearance- pagetoid cells
three types of benign melanocytic naevi
compound intradermal junctional
lentigo maligna melanoma
slow growing black lesion on sun exposed areas of casacioan
superficial spreading melanoma
irregular borders and irregular colour variation
nodular melanoma
in young
acral letiginous melanoma
palms, soles and subungal
stephens johnsons sndrome
<10% skin detachment in sheets nikolsky sign positive if mucosa involved
cuases of stephens johnons syndrome
sulfonamides abx anticonvulsants
pityriasis rosea
slamon pink herald patch followed by christmas tree distribution
causes of pityriasis rosea
viral illness resoves spontaneously