A prospective, double-blind, placebo-controlled single-center, randomized controlled trial to evaluate the efficacy of a multi-strain probiotic on chronic spontaneous urticaria

Chronic spontaneous urticaria (CSU) is a chronic, immune-mediated dermatological disorder characterized by recurrent wheals and/or angioedema without identifiable external triggers. Its pathogenesis is predominantly driven by immune dysregulation, involving mast cell degranulation, histamine release, and autoimmune processes, including autoantibodies targeting IgE or its receptor. Emerging evidence suggests that probiotics may modulate immune responses through mechanisms such as gut microbiota regulation, reduction of systemic inflammation, and enhancement of regulatory T-cell activity, which could benefit patients with CSU. This prospective, single-center, double-blind, placebo-controlled randomized controlled trial aimed to evaluate the efficacy of a multi-strain probiotic as adjunctive therapy in patients with CSU. A total of 97 patients were randomized into two groups: the experimental group received levocetirizine with a multi-strain probiotic, while the control group received levocetirizine with a placebo. Patients intolerant to levocetirizine were administered Bilastine as an alternative. Clinical outcomes were assessed using validated measures, including itch severity, hives severity scores, and the Urticaria Control Test (UCT). Patients in the experimental group demonstrated superior control of itch severity compared to the control group. However, no statistically significant differences were observed in hives severity scores or UCT outcomes between the two groups. These findings suggest a specific benefit of probiotics in symptom reduction when used as an adjunct to standard antihistamine therapy. This study highlights the potential of probiotics as an adjunctive treatment in CSU, particularly in reducing itch severity. The immunomodulatory properties of probiotics provide a promising avenue for future therapeutic strategies in CSU management.