Supplementary Material for: Dapsone in a Large Tertiary Center: Outdated Therapeutic Option or Timeless Agent?

Background: The ancient drug dapsone has antimicrobial and anti-inflammatory features. In dermatology, dapsone is primarily used for neutrophil-dominant skin diseases. However, real-life data assessing the long-term efficacy of dapsone across multiple dermatological diseases is missing. ­Objectives: To determine the efficacy and safety of dapsone in patients with inflammatory skin diseases treated at the Department of Dermatology of the University Hospital Zurich. Methods: The hospital database was searched for patients treated with dapsone in the last 20 years (from January 1, 1998, to December 31, 2017). Overall, 175 patients were included in our study. Results: Thirty-four patients received dapsone for eosinophilic dermatoses, 82 for neutrophilic dermatoses and 59 for other dermatoses. After 3 months, 8% of all patients reached complete remission, 40.6% showed improvement, 30.3% had stable disease, and only 9.1% had disease progression. Final treatment evaluation revealed complete response in 13.2%, disease improvement in 47.4%, stable disease in 25.7% and disease progression in only 12.0%. Patients who showed remission or improvement after 3 months were significantly older than patients with stable or progressive disease. In addition, remission after 3 months was associated with a significantly lower dose of dapsone compared to improvement only. Hemolysis was the most common adverse event (21.7%). Conclusions: Our data show that dapsone is a valid treatment option in various dermatological diseases, leading to a favorable response in the vast majority of patients. In addition, it is well tolerated, safe and inexpensive. Randomized, controlled trials are needed to further elucidate the role of this high-potential drug.