Background: The symptoms of coronavirus disease 2019 (COVID-19) such as hyposmia, rhinorrhea, nasal obstruction, and cough are similar to those of chronic allergic rhinitis. Such symptoms can easily lead allergic rhinitis patients to unnecessary anxiety, misdiagnosis, and invasive diagnostic tests in the COVID-19 pandemic. Interleukin-6 (IL-6) is an important mediator for chronic allergic rhinitis and plays a crucial role in the inflammation of COVID-19.
Houttuynia cordata (HC) has been shown to reduce nasal congestion and swelling by suppressing the activation of IL-6 and is used to fight COVID-19. A novel HC-based Chinese herbal formula, Zheng Yi Fang, was developed to test effects on nasal symptoms of patients with allergic rhinitis in the COVID-19 pandemic.
Methods: Participants aged between 20 to 60 years with at least a 2-year history of moderate to severe perennial AR were enrolled. Eligible participants were randomly allocated to either the intervention group (taking Zheng Yi Fang) or the control group (using regular western medicine) for 4 weeks. The Chinese version of the Rhinosinusitis Outcome Measures was used to evaluate impacts on quality of life and nasal symptoms of participants with allergic rhinitis. In addition, the effect of Zheng Yi Fang on lipopolysaccharide (LPS)-induced IL-6 was investigated.
Results: Participants with allergic rhinitis taking Zheng Yi Fang improved their symptoms of nasal obstruction, nasal secretion, hyposmia, and postnasal drip in comparison with those of the control group. Meanwhile, Zheng Yi Fang exhibited inhibition of IL-6 secretion in the LPS-induced inflammatory model.