IgA pemphigus foliaceus with a clinical presentation of pemphigus herpetiformis.
A patient with clinical features of herpetiform pemphigus of the foliaceus type had histologic findings consistent with pemphigus. Intercellular IgA deposits in a pattern like that of IgG in pemphigus were present. Circulating pemphigus-type IgA-class antibodies reacted first only with guinea pig and later in the disease also with monkey esophagus sections. IgG-class pemphigus antibodies were blocked by the IgA-class antibodies of this patient. In addition, the IgA-class pemphigus antibodies in this patient were blocked by the IgG-class pemphigus antibodies in tests on guinea pig and monkey esophagus. This indicates that the IgA-class antibodies in this patient were directed either to the same antigen as the IgG-class pemphigus foliaceus antibodies or to one that is close enough to it to give steric hindrance. The skin lesions responded poorly to systemic corticosteroid therapy. Dapsone therapy initially produced dramatic improvement, but the condition flared to the point that plasmapheresis, in addition to high doses of corticosteroids and cyclophosphamide, had to be used to control it.