Use of Dapsone in the Treatment of Chronic Idiopathic and Autoimmune Urticaria

Question  What is the efficacy and safety of dapsone in the treatment of chronic spontaneous urticaria?

Findings  In this medical record review, 79 patients with chronic idiopathic or autoimmune urticaria were treated with dapsone. Sixty-two patients experienced improvement, and of these, 29 achieved complete control.

Meaning  Dapsone is an effective and well-tolerated second-line therapy for the treatment of chronic spontaneous urticaria.

Importance  The first-line treatment for patients with chronic spontaneous urticaria (CSU), which is divided into idiopathic and autoimmune subtypes, consists of H₁-antihistamines. However, limited evidence guides the treatment of CSU after maximal therapy with antihistamines fails. Two randomized clinical trials suggest that dapsone may be a successful second-line therapy.

Objective  To evaluate the efficacy and safety of dapsone therapy in patients with CSU.

Design, Setting, and Participants  This retrospective medical record review included 79 patients with CSU treated with dapsone who presented to the tertiary care academic medical center at the New York University School of Medicine, New York, New York, from January 1, 2005, through April 15, 2017. Follow-up was completed on February 28, 2018. Data were analyzed from March 1 through May 31, 2018.

Exposures  Treatment with oral dapsone for CSU.

Main Outcomes and Measures  Efficacy of dapsone therapy for CSU was evaluated as improvement, complete response, and remission.

Results  Seventy-nine patients (65% women; mean [SD] age, 49.8 [16.1] years [range, 20-79 years]) were included in the analysis. Forty-five patients had chronic idiopathic urticaria and 34 had chronic autoimmune urticaria. Improvement in CSU was observed in 62 patients (78%) (36 [80%] with idiopathic and 26 [76%] with autoimmune disease) with dapsone. Mean (SD) time to improvement was 1.1 (1.0) months. A complete response was achieved in 29 (47%) of these 62 patients (16 [44%] with idiopathic and 13 [50%] with autoimmune disease). Mean (SD) time to complete response was 5.2 (5.2) months. Dapsone therapy was tapered in 21 patients after a mean (SD) of 2.4 (2.2) months and discontinued in 18. Ten patients experienced remission with no subsequent flares, even after dapsone therapy was discontinued with follow-up of 0.3 to 10.0 months. Sixteen patients experienced mild adverse effects. Two serious adverse effects were reported.

Conclusions and Relevance  Results of this study suggest that dapsone is a useful and well-tolerated second-line therapy for patients with CSU in whom antihistamines and other first-line agents have failed.