Bullous dermatosis associated with dysglobulinemia (two cases). Relationships with epidermolysis bullosa acquisita.

Two cases of bullous dermatosis with dysglobulinemia are described. The first one was associated with renal and neuromuscular amyloidosis and production of a monoclonal lambda IgG. Optical and electron microscopy showed amyloid deposits beneath basal lamina of the dermis. Results for direct and indirect immunofluorescence (IF) were negative. This bullous dermatosis is not an epidermolysis bullosa acquisita (EBA), in the strict sense, because the amorphous material deposited is amyloid. In the second case, associated with Waldenström's disease, there was no cutaneous or systemic amyloidosis. Direct IF was positive; linear IgM deposits were seen along the basal membrane of the bulla and the healthy skin. Indirect IF showed the presence of circulating antibodies against basal membrane zone. This bullous dermatosis is probably an EBA, despite the absence of IgG deposits. The absence of electron microscopy does not permit the confirmation of this diagnosis.