The clinical and histopathological spectrum of IgA‐pemphigus—report of two cases

Two new cases of neutrophilic bullous disease exhibiting bound and circulating intercellular IgA in viva in both direct and indirect immunofluorescence (IF), for which the term IgA‐pemphigus was recently proposed, are presented. The first case showed a unique constellation of clinical and histopathological features not previously described for IgA‐pemphigus, resembling both dermatitis herpetiformis and pemphigus, for which the designation IgA‐herpetiform pemphigus seems most appropriate. The second case showed clinical and histopathological features mimicking subcorneal pustular dermatosis for which the previously used term IgA‐pemphigus foliaceus seems most appropriate. The previously reported 11 cases showing similar direct IF findings, as well as our two patients, illustrate the main differences between IgA‐pemphigus and classic forms of this condition: (a) different clinical manifestations with the absence of Nikolsky's sign; (b) scanty acantholvsis; an abundance of neutrophils, with occasional neutrophilic spongiosis; (c) absence of C₃ on direct IF; (d) the lower sensitivity of indirect IF and low levels of circulating antibodies; (e) the relatively benign course of the disease; (f) the apparent responsiveness to sulphones in many cases. It is suggested that IgA pemphigus should he considered as an entity separate from, but closely related to, classic pemphigus.