Desensitization to Dapsone in HIV- Positive Patients

To the Editor.  —In a prospective randomized double-blind study reported by Medina et al¹ in The New England Journal of Medicine, dapsone in combination with trimethoprim was as effective as a combination of trimethoprim and sulfamethoxazole (TMP/ SMX) for Pneumocystis carinii pneumonia (PCP) treatment and significantly better tolerated (P =.025). Neutropenia and elevated transaminase levels were five times less frequent in the dapsone group, but cutaneous reactions and nausea and vomiting occurred in equal numbers of patients. For prophylaxis, we reported that oral dapsone (25 mg, four times daily) was equally effective as daily TMP/SMX in preventing PCP with adverse reactions in 10% of those receiving dapsone vs 38% of those receiving TMP/SMX.² These findings and the appearance of other reports of dapsone efficacy in PCP prophylaxis^3,4 prompted us to explore desensitization of patients with the acquired immunodeficiency syndrome (AIDS) demonstrating a clear sensitivity reaction to dapsone.