Histopathologic findings in drug-induced pemphigus

Drug-induced pemphigus represents a diagnostic challenge, as usually no clinical feature differentiates it from its idiopathic counterpart. It was suggested recently that some histologic features may assist in diagnosing drug-associated diseases. The purpose of the study was to determine whether the histologic criteria suggested in the literature are specific enough to arouse suspicion of drug-induced pemphigus. Biopsy specimens of drug-induced and idiopathic pemphigus were reviewed by five dermatopathologists with no clinical data available about the patients. The sections were assessed for the presence of spongiosis with eosinophils, vacuolar degeneration, and the degree of acantholysis and cleavage level. Using the suggested criteria the reviewers were unable to confirm a diagnosis of drug-induced pemphigus. It is advisable to consider drug etiology in every case of newly diagnosed pemphigus based on clinical criteria and detailed drug consumption history, as histologic features do not differentiate between drug-associated and idiopathic disease.