A case of linear IgA disease presenting initially with IgG immune deposits

We describe a case of linear IgA bullous disease initially presenting with histopathologic and immunofluorescent findings consistent with bullous pemphigoid. Initial immunofluorescent studies demonstrated a predominance of linear IgG at the basement membrane zone (BMZ) of perilesional skin and a low titer circulating IgG anti-BMZ antibody. Repeat studies 3 years later revealed a predominance of linear IgA immune deposits at the BMZ and no circulating anti-BMZ antibody. Dapsone therapy was initiated at this time with a good therapeutic response noted. Suction blister studies, immunoelectron microscopy, split skin immunofluorescent studies and Western immune blot were performed and provided indirect evidence that the BMZ antigen in this case is distinct from the bullous pemphigoid antigen component of the BMZ.