Dapsone for immune thrombocytopenic purpura in children and adults.

Dapsone is one of the second line treatments of immune thrombocytopenic purpura (ITP). Dapsone is cheap and has response rates comparable to other second line treatment options like azathioprine, danazol, cyclophosphamide, cyclosporine, and vincristine. This retrospective analysis includes 38 patients (out of total 313 patients) of ITP treated with dapsone from 2004 to 2012. All male patients were screened for G6PD deficiency before starting dapsone. Out of 38 patients (12 children and 26 adults), one was newly diagnosed ITP, seven were persistent ITP, and 30 were chronic ITP. Five patients had side effects of dapsone; two required discontinuation due to skin rashes. The average dose of dapsone was 1.57 mg/kg/day and time to response was 57 days (19-108 days). The response was irrespective of previous treatments and response to them. The response rate was 48.6% (complete response = 40.5%). Only two adult patients had sustained response (> 6 months) after dapsone discontinuation. There were no predictors identified for dapsone response. Dapsone is a safe and cheap second-line therapy for ITP with a response rate of about 50% (majority being CR). A response to dapsone is slow, sustained, and relapses are uncommon on therapy. Dapsone withdrawal leads to relapse in most of the patients.