[Agranulocytosis induced by dapsone prescribed for dermatitis herpetiformis]

Dapsone is a drug widely prescribed in dermatology. It can lead to undesirable side effects including hematologic disorders.

A patient with dermatitis herpetiformis was treated with dapsone. Agranulocytosis developed 6 weeks later and was revealed by fever and pneumonia which resolved under antibiotics. The agranulocytosis regressed without specific treatment after drug withdrawal. Blood counts returned to normal 2 weeks later.

Dapsone-induced agranulocytosis is in common (1/10,000 to 1/20,000). The drug is widely prescribed, particularly for leprosy. Nevertheless, when dapsone is prescribed for dermatitis herpetiformis, the risk of agranulocytosis increases 25-fold reaching 1/400. The indication for dapsone must always made carefully, with surveillance of the blood counts every 15 days during the first 3 months of treatment for dermatitis herpetiformis.