Dermatitis herpetiformis-like changes in cutaneous leucocytoclastic vasculitis with IgA deposition.

Abstract

Summary Histopathological studies in a patient with cutaneous vasculitis revealed sub-epidermal micro-abscess formation as seen in dermatitis herpetiformis (DH). Direct immunonfluorescence of perilesional skin revealed granular IgA fluorescence at the dermo-epidermal junction and deposition of IgA and C3 within vessel walls, whereas immunofluorescence studies of uninvolved skin revealed IgA and C4 deposition within upper dermal vessels only. IgA containing complexes were detected in the serum, and evidence of classical pathway activation was provided by demonstrating CIq and C4 within vessel walls with absence of properdin. Prior to referral there had been a favourable therapeutic response to dapsone. This case illustrates that some forms of leucocytoclastic vasculitis may closely resemble DH and that direct immunofiuorescence of uninvolved skin is required to differentiate the two conditions.