Efficacy of Supportive Therapy of Allergic Rhinitis by Stinging Nettle (Urtica dioica) root extract: a Randomized, Double-Blind, PlaceboControlled, Clinical Trial

Abstract The aim of this study was to survey the exact benefit of this herb in the management of clinical and laboratory signs and symptoms of allergic rhinitis. In a randomized double blind clinical trial, 74 patients with the signs and symptoms of allergic rhinitis and a positive skin prick test were selected and randomly divided into 2 groups who were taken Urtica dioica 150-mg, Urtidin® F.C Tablet) or placebo for one month. Their signs and symptoms, eosinophil percentage on nasal smear, serum IgE, and interleukin IL-4, IL-5, interferon- γ) levels were recorded. Forty patients completed the trial. Based on the Sino- Nasal Outcome Test 22 SNOT-22), a significant improvement in clinical symptom severity was observed in both groups P < .001). Furthermore, a statistically significant reduction in mean nasal smear eosinophil count was observed after treatment with Nettle P < .01). However, the mean IgE and IL4 and IL5 levels in the study group before and after treatment with Nettle saw no significant changes P > .1). Intergroup pre- and post-treatment laboratory findings suggested that there was a significant difference in post-treatment changes of mean IFN γ levels between the study and placebo group P = 0.017). Although the current study showed certain positive effects of Nettle in the management of allergic rhinitis on controlling the symptoms based on the SNOT-22, similar effects were demonstrated by placebo as well. We believe that our limitations underscore the need for larger, longer term studies of Nettle for the treatment of allergic rhinitis.

Keywords: allergic rhinitis; Nettle; Urtica Dioica; cytokine