IgA pemphigus: a case report and its characteristic clinical features compared with subcorneal pustular dermatosis.

We report a case of IgA pemphigus. A 35-year-old woman had vesiculopustular eruptions on her scalp, trunk, and extremities. Histologic examination showed a subcorneal pustule containing numerous neutrophils without acantholysis. Direct immunofluorescence revealed IgA deposits in the intercellular space throughout the epidermis, more intense in superficial layers and less intense in lower layers. The titer of circulating IgA antibodies was 1:160 in normal human skin as a substrate. Skin lesions responded to dapsone. The IgA autoantibody from this patient did not react with desmogleins or desmocollins when immunoblotting, enzyme-linked immunosorbent assay, or complement DNA transfection was used. We consider the characteristic clinical features that favor the diagnosis of IgA pemphigus rather than classic subcorneal pustular dermatosis as follows: (1) the lesions involve the scalp and/or face, and (2) the distribution of the lesions is more widespread.