Dermatitis herpetiformis and linear IgA bullous dermatosis

DH is an uncommon vesicular disease of the skin which has attracted great interest because of myriad clinical and laboratory findings believed to be related to its immunopathogenesis. Investigations have centered on its relationship to gluten intake, multisystem disease associations, pathognomonic patterns of IgA deposition, and impressive therapeutic response to gluten restriction and dapsone. However, a coherent theory of pathogenesis has not yet been established. The circulating antibody responsible for the IgA deposition has not yet been identified, and indirect IF is negative. LABD has now been separated from DH on the basis of its unique immunopathologic finding of linear IgA along the cutaneous basement membrane and the presence of circulating IgA anti-basement membrane antibody, which binds to a 97-kD protein found in normal human skin. It has been suggested that CBDC and LABD are expressions of the same disease process in different age groups rather than two distinct disease processes. Supporting evidence for this theory is based on immunopathologic findings. Linear deposition of IgA along the basement membrane of perilesional skin is identical to LABD and, in addition, a circulating IgA anti-basement membrane antibody is present in the serum of some patients which binds to the 97-kD antigen described in LABD.