Allergic rhinitis (AR) is a type I allergic reaction mediated by specific immunoglobulin E after exposure to allergens in atopic individuals. The main symptoms of AR are nasal congestion, nasal itching, sneezing and rhinorrhea, which are worse at night or early in the morning. The circadian clock is an endogenous timing system in the organism that produces an approximate 24-hour circadian rhythm. The temporal characteristics of the changes in the symptoms of AR coincide with the circadian clock, indicating a close relationship with the biological clock. Taking the biological clock into account during the treatment can be effective in improving symptoms and the quality of life. Intrinsic biological clock molecules in mast cell (MC) regulate its activation through both IgE-dependent and non-IgE-dependent pathways, leading to exacerbation of AR at night or in the early morning. Based on the understanding of the circadian clock, three treatment strategies have been proposed. Chronotherapy reduces side effects and increases efficacy by optimizing the dosing time. Combining chronotherapy with immunotherapy is expected to shorten the duration of treatment. Targeting specific biological clock molecules is expected to be a new option. Disruption of clock genes not only affects changes in the timing of the circadian clock, but can also enhances the severity of allergic reactions and even increases susceptibility to allergic diseases, therefore, lifestyle interventions to maintain intrinsic biological clock homeostasis are critical.

allergic rhinitis  /  circadian clock  /  mast cell  /  chronotherapy  /  immunotherapy