Dapsone in hidradenitis suppurativa: A case series of 56 patients.

Hidradenitis suppurativa (HS) is a chronic inflammatory disease with a challenging treatment. Current guidelines reserve dapsone as a third line agent for patients with mild to moderate HS. To our knowledge, only four small case series have been reported. The objective of this study was to assess the effectiveness and safety of dapsone in our clinical practice. A retrospective observational single-center study of 56 HS patients who underwent treatment with dapsone from May 1, 2015, to June 1, 2021, was performed. The Hidradenitis Suppurativa Clinical Response (HiSCR) scale was used to evaluate the response to treatment. Fifty-six patients were included, 66% of which were men, with a median age of 33 years. Most of them had mild or moderate disease and belonged to LC2 follicular phenotype. All patients had been refractory to first-line treatments. Dapsone was prescribed at doses of 50-150 mg/day. 62.5% of the patients achieved HiSCR after 12 weeks of treatment. No serious adverse reactions were detected. The median duration of treatment was 8 months. After multivariate analysis, an association was found between the presence of fistulous tracts and the risk of non-response to the drug. In four of the dapsone responders, oral retinoids were added to achieve a sustained response. Limitations include the retrospective and non-controlled nature of this study. In conclusion, dapsone is an effective and well-tolerated option for long-term HS treatment, and in this series, it was mainly chosen for patients with LC2 phenotype. It would be interesting to study combination with retinoids and other management options.