Dapsone for Chronic Urticaria

This drug might be an option for patients who don't respond to high-dose antihistamines.

Chronic spontaneous urticaria (CSU; also known as idiopathic urticaria) is characterized by recurring hives and angioedema for longer than 6 weeks. An allergic cause usually is not identified, and as many as 50% of CSU patients probably have an autoimmune cause (i.e., autoantibodies triggering mast cell release). Although such urticaria is self-limited, with a typical duration of 2 to 5 years, it negatively affects quality of life. Only about half of patients improve on high-dose antihistamines. About 60% of antihistamine nonresponders achieve improvement or complete remission with omalizumab (Xolair), which is FDA approved for CSU but is very expensive.

In a retrospective review, researchers analyzed 79 adults with CSU who were unresponsive to antihistamines and who were treated with dapsone. About three quarters of patients showed improvement in ≈1 month, and one third had complete remission at an average of 5 months. Ten patients had prolonged remission after treatment was stopped. Three patients developed anemia, one developed methemoglobinemia, and one had a drug reaction with eosinophilia and systemic symptoms (DRESS).

 Liang SE et al. Use of dapsone in the treatment of chronic idiopathic and autoimmune urticaria. JAMA Dermatol 2018 Nov 21; 155:90. (https://doi.org/10.1001/jamadermatol.2018.3715)