Chronic spontaneous urticaria is marked by recurrent bouts of hives. First line treatment is typically second-generation H1-antihistamines at up to four times the typical dose. But this therapy is unsuccessful in up to 50% of patients. Many other treatments have been tried for chronic spontaneous urticaria. Recently, a medical records review evaluated the use of dapsone in the treatment of chronic spontaneous urticaria. Dapsone is a sulfone antibiotic with both antimicrobial and inflammatory properties.
Among the 79 patients, improvement in chronic urticaria was noted in 62 patients treated with dapsone, with a complete response in 24 patients. Eighteen adverse events were reported, sixteen mild and two serious. Dapsone is well known to cause a decrease in hemoglobin levels, but this is considered a mild side-effect that can generally be managed.
In summary, dapsone can be considered for treatment of chronic urticaria in patients who have failed H1-antihistamine therapy. It has been shown to be an effective and well-tolerated therapy. Results may be seen as early as one month into treatment, but complete response typically took around five months.