Mechanism of Lower Airway Hyperresponsiveness Induced by Allergic Rhinitis Yiting Liu

Allergic rhinitis affects up to 40% of adults and 25% of children globally, however its mechanisms are not yet well elucidated. The majority of people with allergic rhinitis also have lower airway hyperresponsiveness, and an allergic rhinitis occurrence can increase this hyperresponsiveness.

The aim of this review was to understand the mechanism of the effect of allergic rhinitis on the lower airways. The effects of allergic rhinitis on the lower airways were studied in terms of epidemiology, anatomy, pathophysiology, nasal function loss, inflammation drainage, nasobronchial reflex, and whole-body circulatory flow to elucidate the mechanisms involved and provide patterns for future diagnosis, treatment, and experiments.

Researchers concluded that these mechanisms cannot be explained by a single mechanism, but by an interaction of several ones. The hyperresponsiveness of the lower airway may be caused by the rhinopulmonary reflex, lower airway drainage of allergens and nasal obstruction. However, it may also be caused by circulating factors such as IL-5 that stimulate bone marrow cells to differentiate into eosinophils and for IL-4 and IL-13 to upregulate adhesion- and chemotaxis-related proteins. More studies are needed to design future diagnosis and treatment approaches.