Allergic rhinitis, also known as allergic rhinitis, is an allergic reaction that occurs in the nasal mucosa and is a common manifestation of respiratory allergic reactions, sometimes coexisting with bronchial asthma. I. Etiology (a) Genetic factors. (B) nasal mucosal susceptibility susceptibility arises from the frequent stimulation of antigenic substances, but the degree of susceptibility depends on the number of mast cells and basophils in the nasal mucosal tissue and the ability to release chemical mediators. (C) antigenic substances stimulate the body to produce IgE antibodies to antigenic substances called allergens, the allergic substances again into the nasal mucosa, so that combined with the corresponding IgE and cause a metamorphic reaction. The allergens that cause this disease are divided into two categories: inhalational and food-based, according to the way they enter the body. (1) inhalation allergens: pollen, fungi, dust mites, feathers, etc.; (2) ingestion allergens: milk, eggs, fish and shrimp. (2) Pathogenesis: Actually, it is a class I allergic reaction. Clinical manifestations: 1. Treatment: 1. glucocorticoids; 2. antihistamines; 3. mast cell membrane stabilizers; 4. decongestants; 5. antihistamines.