Pemphigus erythematosus induced by thiopronine.

A patient affected by rheumatoid arthritis developed pemphigus erythematosus after 14 months of treatment with thiopronine. The lesions healed spontaneously after 4 weeks' withdrawal of the drug. Whereas the pemphigus erythematosus induced by D-penicillamine is a quite rare but well documented side effect, we believe our case to be the first one reported as being due to thiopronine. It is very interesting to note that the two drugs are very similar with regard to chemical structure, mechanism of action, therapeutic indications and also side effects.