Dermatology Flashcards
pathophysiology of capillary haemangioma
abnormal regulation of vascular stem cells - comprised of proliferating endothelial cells
classification of capillary haemangioma
superficial - upper dermis
deep - lower dermis & subcutaneous tissue
stages of a capillary haemangioma
proliferative - over 8-10m
stabilisation - growth plateaus
regression - lesion involutes over a few years
Rx of capillary haemangioma if near eye
oral propranolol (only after being seen by opthal)
what is morphoea
localised scleroderma
very firm white patches, most commonly thighs, trunk, upper arms
what causes a port wine stain
benign capillary proliferation
when to suspect sturge weber syndrome if patient has a port wine stain
if it is in the distribution of the 1st branch of the trigeminal nerve
presentation sturge weber syndrome
focal epilepsy
LD
glaucoma
stroke-like episodes
Ix for sturge weber syndrome
MRI - will show leptominingeal angiomata
what is HSP
small vessel non granulomatous vasculitis (IgA mediated)
presentation pityriasis rosacea
‘herald patch’ with smaller lesions in a christmas tree distribution (follow the dermatomes)
what is erysipelas
a superficial form of cellulitis
pathophysiology of eczema
? mutation in filaggrin gene - thought to impair skin barrier function
What is seen on histology in eczema
mast cell infiltrates
s/e of topical steroids
telangiectasia
thinning of skin»_space; easy bruising
skin atrophy and thinning
striae
localised hypertrichosis
periorifical dermatitis
pathophysiology of staphylococcal scalded skin syndrome
exotoxin-mediated epidermolysis (toxins A & B)
disrupt the area between the stratum spinosum and the stratum granulosum, causing blistering of the skin
nikolsky’s sign
seen in SSSS
epidermal separation on light pressure with no subsequent scarring
pathophysiology of pemphigus
autoantibodies against desmogleins - molecules attaching adjacent epidermal cells together forming part of the desmosome structure
most common immunoglobulin subtype in pemphigoid
IgG4
what is piebaldism
congenital leucoderma
inheritance of piebaldism
AD
presentation piebaldism
hyperpigmented macules with normal pigementation within the leucoderma
sparing of hands and feet
histological appearance of alopecia areata
T cells within the peribulbar infiltrate
pathophysiology of psoriasis
capillary dilatation within the dermis
T cell mediated cytokines causing overproduction of keratinocytes
what does a skin biopsy in psoriasis show
acanthosis & parakeratosis
Rx psoriasis
- emollients
- tar based bath emollients
- tar and salicylic acid ointments
- vit d analogues
- mild potency topical steroid
presentation dermatitis herpetiformis
itchy papulovesicular rash symmetrically affecting extensor surfaces + back
disease associated with dermatitis herpetiformis
coelaic
Ix for dermatitis herpetiformis
anti-transglutaminase blood test - will be +ve for IgA and IgG antibodies
ichythosis vulgaris presentation
diffuse and persistent scaliness, white to dirty grey colour
extensor surfaces most common
pompholyx presentation
sudden onset of clear vesicles affecting Sides of fingers, toes, palms, soles
presentation epidermolysis bullosa
simplex is reserved to sites of friction e.g palms and soles when starts to walk or crawl
whitehead aka
closed comedome
blackhead aka
open comedome
where are melanocytes found
epidermis
