Objective: Although the role of oxidative stresses has been confirmed in the pathophysiology of allergic rhinitis and the protective effect of silymarin against oxidative stresses has been proven in different organs, no study has yet been conducted on the impact of silymarin on allergic rhinitis treatment.
Study design: A randomized clinical trial study.
Setting: Two tertiary referral centers with otorhinolaryngology-head and neck surgery and allergy and immunology departments.
Patients and methods: In a randomized clinical trial, 94 patients with the signs and symptoms of allergic rhinitis and a positive skin prick test were selected and randomly divided into 2 groups. Their signs and symptoms, eosinophil percentage on nasal smear, serum IgE, and interleukin (IL-4, IL-5, interferon-γ) levels were recorded. The study group was treated with silymarin, whereas the control group received placebo, both for 1 month, along with routine antihistamine treatment. At the end of the treatment course, clinical and laboratory findings were statistically analyzed.
Results: Sixty patients completed the trial. Based on the Sino-Nasal Outcome Test 20 (SNOT-20), a significant improvement in clinical symptom severity was observed in both groups (9.23 ± 5.14 vs 2.20 ± 2.69; P < .001), which was statistically significantly higher in the study group (P < .001). Posttreatment percentage of nasal eosinophils and cytokine levels showed no significant difference (P > .05). Rise in serum IgE level was seen after treatment with silymarin (P = .003).
Conclusion: Considering the statistically effective role of silymarin in alleviating the severity of allergic rhinitis symptoms, applying this herbal antioxidant along with other medications may result in better management.