Prospective randomized non‐blinded clinical trial on the use of dapsone plus antihistamine vs. antihistamine in patients with chronic idiopathic urticaria

Abstract Background Treatment of chronic idiopathic urticaria (CIU) is difficult. Objective The purpose of this study was to evaluate the efficacy and safety of dapsone in CIU. Methods The response to dapsone was evaluated in 65 CIU patients with a randomized, two armed study: 3‐month dapsone + desloratadin and 3‐month desloratadin. All were followed for up to 3 months and 3 months after; all took desloratadine 10 mg daily throughout the study. The primary measure of efficacy was a daily urticaria activity score (UAS) of weal numbers and itch (maximum score, 42 per week). Results Sixty‐five patients completed the randomized 3‐month trial medication. Mean reduction in UAS from baseline at 3 months was 7 [95% confidence interval (95% CI), 6.92–7.08] for active group and 5.77 (95% CI, 5.47–6.08) for control subjects ( P < 0.001). The reduction in visual analogue score (VAS) at 3 months for active group (mean, 2.58; 95% CI, 2.33–2.83) and control subjects (mean, 2.55; 95% CI, 2.38–2.73) was also significant ( P < 0.001). The reduction of UAS and VAS at 3 months compared between active group and control subjects showed no significant difference. Mean reduction in UAS from the end of the study at 3 months after was 1.16 and –4.8 for active and control subjects, respectively. These results were compared with each other, and it was statistically significant ( P ≤ 0.05). Limitations No placebo was used. The study was not blinded. Lack of blinding may have led to bias. The follow‐up period was short. Conclusion This study shows that dapsone leads to a persistent decrease in VAS and UAS and is associated with complete remission in some patients.