Allergies are not infectious diseases and are not contagious, but are pathological reactions to certain otherwise harmless substances such as pollen, dust mites, molds, foods, medications, etc. Allergies are caused by both intrinsic and extrinsic environmental factors. The intrinsic factor is usually the patient’s own allergy. Allergy plays a leading role in the development of allergy, early and thorough desensitization is the key to treating allergy and preventing recurrence. There are also many external factors, including diet, inhalants, climate, contact with allergens and other factors, of which seafood, proteins, spicy foods, alcohol, inhalation of pollen, dust mites, cold weather, contact with chemicals, soaps, detergents and so on are the most common triggers of allergies. Once an allergy occurs, it is necessary to go to the allergy department of the hospital as soon as possible for allergen testing and treatment, and usually avoid contact with allergens; if the air quality is not good, wear a mask to reduce the stimulation of the respiratory tract; at the same time, it is necessary to carry out reasonable dietary adjustments, appropriate physical exercise, to ensure adequate sleep, and to improve the body’s immunity.