Immunoglobulin A dermatoses

Immunoglobulin A (IgA) dermatoses are a diverse group of conditions in which the disease process occurs directly from IgA in the lesional or perilesional skin. This group of diseases has in common the presence of a neutrophil-rich inflammatory infiltrate and pharmacologic responsiveness to dapsone therapy. The cellular receptor for IgA (FcaR1) are of limited distribution (predominantly neutrophils), which may, in part, explain the neutrophil-rich infiltrates observed in these disorders. Engagement of the IgA receptor can activate neutrophils to degranulate, mediate cytotoxicity, develop a respiratory burst, and activate endocytosis. All of these activation processes are likely to play a role in the tissue damage that is observed in the IgA dermatoses. This group of diseases includes dermatitis herpetiformis, linear IgA bullous dermatosis, IgA pemphigus (both subcorneal and intraepidermal types), and Henoch-Schönlein purpura.