Herbal Medicines for Allergic Rhinitis: a Systematic Review and Meta-analysis.

PURPOSE OF REVIEW

To assess the effects of herbal medicine (HM) therapy in various durations and analyze the effects of HM separately by mechanism of action in the treatment of allergic rhinitis (AR).

RECENT FINDINGS

Thirty-two studies were included (2,697 patients, mean age 34.6 years). For the ≤ 4 weeks of treatment duration, HM brought greater benefits over placebo in reduction of total nasal symptoms score (standardized mean difference (SMD) -0.68; 95% confidence interval (CI) -0.98, -0.38; p <0.01) and improvement in Rhinoconjunctivitis Quality of Life Questionnaire score (SMD -0.53; 95% CI -0.81, -0.25; p <0.01). For the 4-12 weeks duration, total nasal symptoms score (SMD -0.22; 95%CI -0.4, -0.05; p =0.01) and Rhinoconjunctivitis Quality of Life Questionnaire score (SMD -0.48; 95% CI -0.89, -0.06; p =0.03) favored the HM. However, HM therapy for longer than 12 weeks was related to tachyphylaxis and showed no benefit over placebo in any outcomes. There was no difference between the HM and standard treatment on symptoms improvement. Anti-allergic effect, anti-inflammatory effect, anti-leukotriene effect, and anti-histaminic effect of HM were revealed. HM was safe and their adverse effects were comparable placebo. HM therapy is safe and provides better results than placebo in improving nasal symptoms and disease-specific quality of life in patients with AR. Its beneficial effects are demonstrated only in less than 12 weeks of treatment.

TRIAL REGISTRATION

PROSPERO ID: CRD42020168367.