Intercellular IgA dermatosis of childhood. Selective deposition of monomer IgA1 in the intercellular space of the epidermis.

We describe a 7-year-old girl with recurrent pruritic vesiculopustular lesions involving the trunk, extremities, face, and oral mucosa. Histopathologic examination revealed intraepidermal bullae containing neutrophils and eosinophils, and direct immunofluorescence test showed the deposition of IgA in the intercellular space of the epidermis. Circulating IgA anti-intercellular antibodies were also detected by indirect immunofluorescence test. Immunofluorescence studies using monoclonal antibodies to human IgA subclasses showed that these IgA antibodies belonged to IgA1. Antisera against J chain and secretory component did not show any specific intercellular staining. Surface IgA(+)-B cells were transiently increased in the peripheral blood during the active stage of the disease. These results indicated the extragut origin of these IgA antibodies. Dapsone therapy was shown to be very effective.