I am often asked by patients: Should I have desensitization therapy? My usual answer is: Not recommended. The following is the basic knowledge and personal understanding of desensitization therapy. 1.Introduction Desensitization therapy, also known as hyposensitization therapy, or specific immunotherapy method, is to make a certain concentration of leachate of the main antigenic substance that cannot be avoided and confirmed or suspected by skin test or other methods, and to inject, contain, or percutaneously infiltrate with gradually increasing doses and concentrations, so that by repeatedly feeding specific antigens to patients, the corresponding antibodies can be generated in the body, thus achieving immune tolerance. The common clinical desensitization therapies are: injection desensitization, sublingual desensitization, and desensitization patch. When these specific antibodies are raised in body fluids, such as when receiving foreign specific allergens again, these antibodies will first bind to them and compete with the original IgE antibodies in the body, thus producing an immune response without producing an allergic reaction. After continuous desensitization treatment, the serum IgE gradually decreases to below the threshold of allergic reaction, which prevents the occurrence of allergic reaction and thus achieves the purpose of desensitization. 3. Types of allergens and methods of finding them In short, desensitization treatment is like a one-to-one battle, that is, one antibody corresponds to one allergen, so the first step of treatment is to “find the allergen”. The antigen that triggers an allergic reaction is called an allergen, and allergens are necessary for allergies to occur. There are 2,000-3,000 common antigenic substances that cause allergic reactions, and nearly 20,000 in the medical literature. They are inhaled, ingested, injected or contacted to cause allergic phenomena in the body. Common allergens are as follows: (1) Inhalation allergens: such as pollen, willow wool, dust, mites, animal dander, oil fumes, paint, car exhaust, gas, cigarettes, etc. (2) Ingested allergens: such as milk, eggs, fish and shrimp, beef and mutton, seafood, animal fat, allogeneic proteins, alcohol, drugs, antibacterial agents, anti-inflammatory drugs, fragrance oil, flavoring, onion, ginger, garlic, and some vegetables, fruits, etc. (3) Contact allergens: such as cold air, hot air, ultraviolet light, radiation, cosmetics, shampoo, detergent, hair dye, soap, chemical fiber products, plastic, metal jewelry (watches, necklaces, rings, earrings), bacteria, mold, viruses, parasites, etc. (4) Injectable allergens: such as penicillin, streptomycin, heterologous serum, etc. (5) Self-tissue antigens: Self-tissue antigens affected by biological and physicochemical factors such as mental stress, work stress, microbial infections, ionizing radiation burns, and other structural or compositional changes, as well as self-hidden antigens released due to trauma or infection, can also become allergens. At present, there are four main methods to find allergens: (1) intradermal method (2) intradermal threshold method (3) scratch prick method (4) a variety of simultaneous specific antibody allergy test (5) skin prick test (the method is more commonly used in clinical practice) 4, desensitization process Desensitization treatment can be carried out only after the allergen is clarified. Desensitization injections start with a small dose and gradually increase the dose to increase the tolerance to the allergen. Desensitization treatment generally takes at least 2 to 3 years. 5. Personal views on desensitization therapy Through the above, there are two basic understandings of desensitization therapy: the definite allergen must be found; and the treatment time is long. Through these two basic understandings, we can see the disadvantages of desensitization therapy: (1) For allergies caused by antigens of one’s own tissue, no clear allergen can be found at all, so desensitization cannot be carried out at all. Moreover, there are many different types of allergens, which vary from person to person, and few of them can be detected at present, so it is impossible to desensitize all allergic patients. (2) The treatment period is too long, usually 2-3 years, and long-term injections can cause a lot of pain.