Dapsone syndrome in cutaneous lupus erythematosus.

Dapsone is increasingly used in the treatment of rheumatic diseases. It is indicated in many inflammatory skin conditions characterized by polymorphonuclear cell infiltration. Minor reactions to the drug are very common, but severe idiosyncratic reactions are rare considering the large number of patients taking this drug worldwide. We describe 2 patients with cutaneous lupus erythematosus who developed severe dapsone reaction after low dose therapy, with a fatal outcome in one. Physicians should be aware of the potentially lethal side effects of dapsone.