Dapsone-Induced Motor Polyneuropathy: A Complication of Prolonged Treatment of Subcorneal Pustular Dermatosis

• A motor polyneuropathy developed in a woman with subcorneal pustular dermatosis of 16 years' duration, who had received at least 300 gm of dapsone over a five-year period and 80 gm during the four-month period of progression of her neurologic symptoms. Although the patient believed her muscle power had returned to normal four months after the drug was stopped, a slight peripheral neuropathy remained. Electrodiagnostic and clinical features during the period of greatest weakness and the subsequent 16 months were consistent with a polyneuropathy of the axonal type. The neurotoxicity of dapsone appears to be dosedependent, but the mechanism by which it occurs is unknown. ( Arch Dermatol 112:1158-1160, 1976)