Perforating dermatosis in a patient receiving azathioprine.

Azathioprine (AZA) is an imidazole derivative of mercaptopurine. It antagonizes purine metabolism, and it may inhibit synthesis of DNA, RNA, and proteins. The 6-thioguanine nucleotides appear to mediate the majority of AZAs immunosuppressive and toxic effects. While cutaneous adverse side-effects are not uncommon, perforating dermatosis has not been reported in association to AZA. We speculate that immunological disorders induced by AZA in susceptible individuals could be related to perforating dermatosis.