Allergic rhinitis is caused by a combination of factors, but mainly allergic reaction occurs when atopic constitution comes into contact with allergens, including inhalation allergens, food allergens and so on. The differences in individual constitution are manifested in certain differences in reactivity and adaptability to external stimuli under physiological state, as well as the susceptibility to certain pathogenic factors and the tendency of disease development in the process of pathogenesis. Atopic constitution is a kind of constitution or systemic state that is susceptible to allergic diseases. 1. Inhalation allergens: most of them are caused by allergens in the environment, such as dust mites, pollen, fungi, animal dander, etc., which may cause strong allergic reactions in the nasal mucosa. 2. Food allergens: There are also a few cases of allergic rhinitis caused mainly by food intake, such as allergy to nuts, peanuts, mangoes, etc., which trigger allergic rhinitis. Allergic rhinitis often leads to paroxysmal sneezing, watery, runny nose and other symptoms, once the onset of the need to cooperate with the doctor for timely treatment.