bullous disorders Flashcards
what is the primary feature of bullous disorders
blisters
how do you differentiate between bullous pemphigoid and pemphigus vulgaris
pemphigoiD = Deeper, through the dermal junction
pemphiguS= Shallow, Superficial , intra-epidermal
what are the investigations of bullous disorders
skin biopsy with direct immunofluorescence
indirect immunofluorescence
what is the treatment of bullous disorders
systemic steroids or other immunosuppressive agents
emollients
antisepsis/hygiene measures
describe bullous pemphigoid
sub-epidermal blisters with no evidence of acantholysis
what causes bullous pemphigoid
circulating IgG react with major and/or minor antigens of the hemidesmosomes anchoring basal cells to the basement membrane resulting in local complement activation and tissue damage
describe the appearance of bullous pemphigoid
localised to one area or widespread on trunk and proximal limbs
large, tense bull with erythematous base on normal skin
blisters burst to leave erosions but do not scar
urticated, itchy erythematous plaques and papules in early disease
what causes pemphigus vulgaris
IgG auto-antibodies against desmoglein 3
what is desmoglein 3 responsible for
maintaining desmosomal attachments
describe the appearance of pemphigus vulgaris
typically affects scalp, face, axillae and groin
flaccid vesicles/bullae, thin roofed
lesions rupture to leave raw areas
acantholysis
Nikolsky is positive
mucosal involvement is very common (e.g. eyes, genitals)
what is Nikolsky sign
top layers of skin will slip away from the lower layers when slightly rubbed. this indicated a plane of cleavage WITHIN the epidermis
what is the treatment of pemphigus vulgaris
normal bullous disorder treatment
what is dermatitis herpetiform
rare autoimmune bullous disease
what is dermatitis herpetiform strongly associated with
coeliac disease
what causes dermatitis herpetiform
IgA is deposited in the dermal papillae. the IgA antibodies target gliadin component of gluten but cross-react with connective tissue matrix proteins. immune complexes form in dermal papillae and activate complement to generate neutrophil chemotaxis
