Allergic rhinitis, or allergic rhinitis, is a non-infectious inflammatory disease of the nasal mucosa in which the exposure of an atopic individual to an allergen results in the release of mediators (mainly histamine) mediated mainly by IgE, with the involvement of a variety of immunoreactive cells and cytokines, etc. There are 3 necessary conditions for its occurrence: the specific antigen, i.e., the substance that causes the immune response of the body; the atopic individual, i.e., the so-called individual differences, allergic body; and the encounter between the two, the specific antigen and the atopic individual. Allergic rhinitis is a global health problem that can lead to many diseases and loss of workforce. Etiology Allergic rhinitis is a multifactorial disease induced by the interaction of genes and the environment. Risk factors for allergic rhinitis may be present in all age groups. 1. Genetic factors Patients with allergic rhinitis have an atopic constitution and usually show familial aggregation, and certain genes have been found to be associated with allergic rhinitis. 2, allergen exposure Allergens are antigens that induce specific IgE antibodies and react with them. They are mostly derived from animals, plants, insects, fungi or occupational substances. Their composition is proteins or glycoproteins and very rarely polysaccharides. Allergens are mainly divided into inhalant allergens and food allergens. Inhaled allergens are the main cause of allergic rhinitis. (1) Mites: The most important mites in subtropical and tropical areas are house dust mites and dust mites. House dust mites feed on human dander and live mainly in mattresses, bed bottoms, pillows, carpets, furniture and plush toys. They reproduce fastest in hot (above 20°C) and humid (relative humidity >80%) environments. House dust mite allergens are contained in their excrement particles, which are exposed to the air and can be quickly re-deposited when the contaminated fabric is touched. The concentration of mite allergens in the air is associated with the onset of allergic rhinitis. (2) Pollen: Wind-borne pollen can affect people hundreds of kilometers away from the pollen source because of its huge dispersion and ability to travel long distances. Insect-borne pollen can only be sensitized by direct contact, such as agronomists and florists. The allergenic capacity of pollen varies with season, geographic location, temperature and plant species. Most pollen sensitizers will suffer from conjunctivitis. (3) Animal dander: Animal dander and secretions carry allergens. Cat and dog allergens are widely present in house dust and furniture decorations. (4) fungal allergens: molds release allergenic spores into the indoor and outdoor environment, and grow rapidly in hot and humid environments. (5) Cockroach allergens: Allergens are found in their feces and carapace, and the particles are large and not dispersed in the air. (6) Food allergens: When allergic rhinitis is not accompanied by other systemic symptoms, food allergic reactions are rare. On the other hand, food allergic reactions are common in cases where the patient has multiple organ involvement. In infants, most are caused by milk and soy; in adults, common food allergens include: peanuts, nuts, fish, eggs, milk soy, apples, pears, etc.