Subcorneal pustular dermatosis associated with IgA myeloma and intraepidermal IgA deposits.

We report a 59-year-old woman who had subcorneal pustular dermatosis and IgA-kappa myeloma. Immunofluorescence tests showed intercellular IgA-kappa deposits in the upper portion of the lesional epidermis and circulating IgA-kappa anti-intercellular autoantibodies in a titer of 1:40. A combination chemotherapy for myeloma induced dramatic improvement of the skin lesions in accordance with a marked decrease in serum IgA levels as well as the disappearance of circulating anti-intercellular IgA autoantibodies, suggesting a pathogenetic link between skin lesions and IgA-kappa paraprotein produced by myeloma cells.