Cefadroxil-induced ampicillin-exacerbated pemphigus vulgaris: case report and review of the literature.

A 77-year-old patient is described who developed pemphigus vulgaris temporally with the administration of cefadroxil. The disease improved when the drug was discontinued but was exacerbated with the administration of ampicillin. This may be the first case of possible cefadroxil-induced and only the second case of ampicillin-induced pemphigus vulgaris reported. The pathophysiology, diagnosis, and treatment of pemphigus vulgaris is briefly described. Drug-induced pemphigus is reviewed. By far the most incriminated drug has been penicillamine. It is postulated that the sulfhydryl group of penicillamine alters the intercellular cement substance into an antigenic structure with subsequent antibody formation. The chemical similarity between penicillamine, the penicillins, and the cephalosporins is alluded to and the potential for cross-sensitivity between the penicillins and cephalosporins is emphasized. Although the pemphigus vulgaris could have occurred by chance, it seems probable that it was drug-induced.