I. What is an allergen? The substance that induces an allergic reaction is called an allergen. There are hundreds of substances that cause allergic reactions. They can sensitize the body through inhalation, ingestion, injection or contact. Second, the type of allergens? 1, inhalation allergens: pollen, willow, dust, mites, animal dander, oil smoke, paint, car exhaust, gas, cigarettes, etc. 2. Ingested allergens: milk, eggs, fish and shrimp, beef and mutton, seafood, allogeneic proteins, alcohol, drugs, antibacterial agents, fragrance oils, flavors, onions, ginger, garlic, and some vegetables and fruits, etc. 3, contact allergens: cold air, hot air, ultraviolet light, radiation, cosmetics, shampoo, detergent, hair dye, soap, chemical fiber products, metal jewelry, bacteria, mold, viruses, parasites, etc. Third, what are the examination methods of allergens? 1, mainly by medical history, pay attention to the onset of the disease, environmental factors, dietary habits, the presence of animal breeding, etc.. It may be possible to find allergens. 2, in vivo allergen test, intradermal test is now commonly used to check allergens, this method requires patients to stop using anti-allergy drugs for more than 3 days, about half an hour out of the results, the price is relatively low, check the variety of up to 40 kinds. 3, in vitro serum specific immunoglobulin assay. By taking peripheral venous blood for examination, more than 20 kinds of allergens can be detected. But it is more expensive. The results are not available at the time. What is desensitization treatment? Desensitization treatment is the injection of specific allergen vaccine, starting from a small tolerated dose and regularly increasing the dose until the maximum tolerated amount, so as to achieve the purpose of no further exposure to allergens or significant reduction of symptoms. In principle, treatment usually lasts 2-3 years. Treatment is continued for one year after the disappearance of symptoms. The success rate of treatment for allergy to grass, tree and other plant pollen is about 90%, and for allergy to house dust mites about 70-80%. V. What are the advantages of desensitization treatment? 1. For allergens that cannot be avoided, desensitization therapy is the only allopathic treatment and the only possible cure. 2. It can avoid the development of allergic rhinitis into bronchial asthma in children. 3.To avoid the development from allergy to a single allergen to allergy to multiple allergens. 4.Side effects are rare. Long-term use of hormones and other side effects can be avoided. 5.Improve the quality of life. VI. What is the scope of application of desensitization therapy? Desensitization therapy is only applicable to allergic diseases, such as allergic rhinitis, conjunctivitis, allergic asthma, allergic eczema, urticaria, intestinal allergic diseases.