Bullous disorders Flashcards
what are bullous disorders
autoimmune diseases with damage to adhesion mechanisms
diagnosis of bullous disorders
- Nikolsky’s sign
- skin biopsy with direct immunofluorescence
- indirect immunofluorescence
what does immunofluorescence of pemphigoid show
linear IgG and complement deposited around BM
bullous disorders management
systemic steroids
immunosuppressive agents
emollients, topical steroids and antiseptics
pemphigoid management
tetracycline
define pemphigus
autoimmune condition with IgG autoantibodies to desmolgein 3 which maintains desmosome attachments
immunology of pemphigus
immune complexes form on cell surface causing complement activation and protease release, end is acantholysis (loss of coherence between keratinocytes)
what happens when blisters rupture in pemphigus
cause shallow erosions
areas involved in pemphigus
scalp face axillae groin trunk mucosal surfaces e.g. mouth and respiratory tract
define pemphigoid
sub epidermal blisters with no acantholysis
immunology of pemphigoid
- circulating IgG react with antigens on hemidesmosomes anchoring basal cells to the basement membrane
- result is local complement activation and tissue damage
- blisters form between basal layer and dermal papillae
define dermatitis herpetiformis
autoimmune disease with strong association to Coeliac’s disease and HLA-DQ2
presentation of dermatitis herpetiformis
itchy
symmetrical lesions
elbows
knees
hallmark of dermatitis herpetiformis
papillary dermal micro abscesses with deposits of IgA
IgA in dermatitis herpetiformis
targets gliadin in gluten and cross-reacts with connective tissue matrix proteins causing immune complexes in dermal papillae and complement and neutrophil activation
