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

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
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.