Intercellular IgA dermatosis

We report three cases of intercellular IgA dermatosis (IAD) and review the literature. IAD is a spectrum of vesiculobullous or vesiculopustular diseases mediated by intercellular IgA deposition. The clinical picture may vary from a vesiculopustular eruption with centrifugal evolution mainly involving the trunk and extremities, to the typical picture of classic pemphigus variants (foliaceus, vegetans). Histologically, infiltrating polymorphonuclear cells (mainly neutrophils) are observed in the epidermis with formation of pustules and bullae at various levels. However cases with typical histological features of pemphigus (variants) are described. Direct immunofluorescence on perilesonal skin typically displays intercellular IgA deposition at different levels or throughout the epidermis and indirect immunofluorescence often detects low levels of circulating antibodies. The disease has been repeatedly reported in association with monoclonal IgA gammopathy. Most cases respond to dapsone. In some cases IgA is directed against known pemphigus antigens whereas their targets in other cases are newly discovered antigens (105 kD, 115 kD, 120 kD). We observe a heterogeneity within the clinical, histological and immunological characteristics of the disease. Many reported cases feature various combinations of these characteristics. We therefore consider IAD as a disease spectrum with IgA pemphigus (clinical and histological pemphigus) at one end and intercellular IgA vesiculopustular dermatosis at the other end.