Dapsone useful for chronic spontaneous urticaria

11/30/2018

By Marilynn Larkin

NEW YORK (Reuters Health) - Dapsone is an effective second-line treatment for chronic spontaneous urticaria (CSU) patients in whom antihistamines and other first-line therapies have failed, researchers say.

Research fellow Erik Peterson and colleagues at NYU Langone Health in New York City studied medical records of 79 patients (mean age, 50; 65% women) treated with dapsone for CSU from 2005 to 2017. Forty-five patients (60%) had chronic idiopathic urticaria and 34 had chronic autoimmune urticaria.

As reported online November 21 in JAMA Dermatology, dapsone resulted in improvement in CSU in 62 patients (78%): 36 (80%) with idiopathic and 26 (76%) with autoimmune disease. The mean time to improvement was about a month.

A complete response was achieved in 29 (47%) of the 62 responders: 16 (44%) with idiopathic and 13 (50%) with autoimmune disease. The mean time to complete response was 5.2 months.

Dapsone was tapered in 21 patients after a mean of 2.4 months and discontinued in 18. Ten patients followed for up to 10 months experienced remission with no subsequent flares, even after dapsone was discontinued.

Sixteen patients experienced mild adverse effects. Two patients had serious adverse events requiring cessation of therapy: one methemoglobinemia and one drug reaction with eosinophilia and systemic symptoms.

"As an efficacious, well-tolerated medication...dapsone merits further usage as a second-line therapy in the treatment of refractory CSU," Peterson said in an email to Reuters Health. "Comparative studies could evaluate dapsone's utility against other second-line agents, such as biologics like omalizumab, immunosuppressants like cyclosporine, or steroids like prednisone."

"However, many patients in our study had previously failed these second-line therapies and only achieved disease control with dapsone," he noted. "Furthermore, dapsone offers an advantage over other systemic medications due to its tolerability and low side-effect profile."

"Dapsone merits further investigation to determine the precise mechanism by which this anti-microbial agent can provide such a robust and durable response for patients suffering from CSU," he concluded.

Dr. Suzanne Friedler, a clinical instructor of dermatology at the Mount Sinai Health System in New York City, told Reuters Health by email, "Chronic idiopathic and autoimmune urticaria present a difficult therapeutic challenge when they do not respond to conventional therapy."

"Dapsone is an interesting alternative (to other second-line therapies) because it has anti-microbial and anti-inflammatory properties," she noted. "It is a fraction of the cost of biologic therapy and it may have lower side effects than long-term steroid use."

Because dapsone can cause a hemolytic anemia in patients with glucose 6 phosphate dehydrogenase deficiency, "patients are always screened for this before starting dapsone," she added.

SOURCE: http://bit.ly/2E7gAun

JAMA Dermatol 2018.

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