Derm- blistering skin disorders Flashcards
what is a bullae
large, fluid filled blister on the skin
what is bullous pemphigoid
subepidermal blister caused by an autoimmune reaction
how old are patients typically who have bullous pemphigoid
elderly (>60)
which type of hypersensitivity reaction is bullous pemphigoid
type II
is bollous pemphigoid nikolsky sign positive or negative?
negative
in bollous pemphigoid- Which antibodies react with the antigen of hemidesmosomes that anchor basal cells to the basement membrane?
anti-hemimesmosome antibodies (igG)
main investigation for bollous pemphigoid
biopsy- immunofluorescence
management of localised bullous pemphigoid
High potency topical steroids at onset of symptoms e.g. itch
what is pemphigus vulgaris
One of the autoimmune blistering skin conditions characterised by flaccid intra-epidermal blisters
when does pemphigus vulgaris usually present
middle age
drug triggers of pemphigus vulgaris
ACEi
penicillamine
which type of hypersensitivity reaction is pemphigus vulgaris
type II
is nikolsky sign positive or negative with pemphigus vulgaris
positive
common sites for pemphigus vulgaris
mocosal surfaces
face
scalp
axillae
groin
trunk
biopsy Immunofluorescence shows what in pemphigus vulgaris?
IgG in “chicken wire” pattern
biopsy Immunofluorescence shows what in bullous pemphigoid?
linear band of IgG
which antibodies are likely to be present in a patient with bullous pemphigoid
Anti-BP180 and anti-BP230 antibodies
what is dermatitis herpetiformis
autoimmune bullous disorder associated with coeliac disease
pathophysiology of dermatitis hereptiformis
igA antibodies cross react with TTG
biopsy Immunofluorescence shows what in dermatitis herpetiformis?
granular deposits of IgA in dermal papillae
drug used to treat dermatitis herpetiformis
dapsone
pemphigUS and pemphiguS =
epidermUS
Superficial
pemphigoiD =
Deep
what type of hypersensitivity reaction is dermatitis herpetiformis
type III
what is Stevens-johnson syndrome
immune-complex-mediated hypersensitivity disorder. ranges from mild-severe with TEN being most severe form
predominant cause of SJS
adverse drug reaction
drugs that are most common cause of SJS adverse drug reactions
sulfonamides
beta-lactams (penicillins and cephalosporins)
antiepeleptics
allopurinol
NSAIDs
triggers of SJS
drug reactions
infections- HSV, HIV, influenza, Epstein barr virus, hepatitis
bacterial and fungal infections less common
Nikolsky sign positive/negative in SJS
positive
what is seen in at least two places with SJS
mucosal ulceration
mortality rate in SJS
10%
what is the definitive investigation to diagnose Stevens-johnson syndrome
skin biopsy
what shape are the lesions seen in SJS
target shaped
what is erythema multiforme
immune-mediated condition characterised by typical or atypical target lesions and potential blistering
most common cause of erythema multiforme
infections- most common hsv
which cell mediates erythema multiforme
delayed T cell mediated skin reaction
what is erythema multiforme minor
does not involve mucous membranes
usually triggered by an infection
what is erythema multiforme major
does involve mucous membranes
more commonly drug-induced
how many colours are typical erythema multiforme lesions
three
how many colours are atypical erythema multiforme lesions
two
where do erythema multiforme rashes usually develop before spreading to rest of body
palms and soles
