Analysis of 6 cases of drug-induced pemphigus.

To study clinical and laboratory characteristics of drug-induced pemphigus. Using direct immunofluorescence (IF), indirect IF, ELISA and immunoblotting to characterize 6 patients with drug-induced pemphigus (DIP) and compared them with 20 cases of idiopathic pemphigus. All the 6 cases of DIP showed obvious itching (100%) and no damage to the oral mucosa. Five out of 6 DIP cases (83.33%) presented as pemphigus folicaeus (PF) since they contained circulating Dsg1-specific IgG, were sensitive to low doses of glucocorticoid, and had good prognosis. One case was showed as pemphigus vulgaris (PV). Dsg1-specific IgA was positive in peripheral blood of 4 cases (66.67%), and the antibody disappeared after treatment. In patients with idiopathic pemphigus, only 6 cases (30%) had mild itching, and 12 cases (60%) had oral mucosal lesions. Twelve cases (60%) were PV with anti-Dsg1 and -Dsg3 antibodies, and 8 cases (40%) were PF with anti-Dsg1 antibody only. One case (5%) had anti-Dsg1 IgA. Drug factors should be considered for pemphigus as some common antibiotics can cause pemphigus.