What is Pemphigus?
An autoimmune condition characterised by fluid filled blisters on skin (and eyes and genitals) can be fatal if extensive mucosal involvement
high mortality rate
What is the pathophysiology of pemphigus?
IgG autoantibodies are made against desmoglen 3 which maintains desmosomal attatchments.
Therefore immune complexes form on cell surface and complement is activated and proteases are released
This disrupts desmosomes and leads to acantholysis
What is nickolsklys sign?
when the skin is rubbed it falls away - acantholysis
Is pemphigus nickolskly sign positive or negative?
positive
How is pemphigus investigated?
skin biopsy with immunofloresence or indirect immunofloresence
How is pemphigus treated?
steroids - either topical or systemic
What is bullus pemphigoid?
subepidermal blister (in dermal-epidermal junction)
What is the pathophysiology of bullus pemphigoid?
circulating IgG antibodies react with antigens of hemidesmosomes which anchor basal cells to the basement membrane
This causes complement activation and tissue damage
How does bullus pemphigoid present?
itchy erythemous plaques and papules
mainly affects elderly
nickolsky sign negative
How is bullus pemphigoid treated?
tetracycline
What is dermatitis herpetiformis?
intensly itchy lesions on elbows, knees and buttocks
What is the hallmark of dermatitis herpetiformis?
papillary dermal microabscesses
What is dermatitis herpetiformis associated with?
coeliac disease and HLA-DQ2 haplotype
antibodies target gliadin component and cross react with connective tissue matrix proteins
immune complexes form in dermal papillae and generate neutrophil chemotaxis