Allergic diseases, also known as allergic diseases, are diseases in which the body, through inhalation, ingestion, injection or contact with a substance, including antigenic substances or semi-antigenic substances, causes an excessive reaction in a tissue or organ, or even a systemic reaction, resulting in various dysfunctions or tissue damage, such as allergic skin diseases and allergic rhinitis, bronchial asthma, etc. With the development of industrial economy, the change of ecological environment and the increasing richness of human material life, people are exposed to more and more allergenic substances, leading to an increasing incidence of allergic diseases. The causes of allergic diseases are complex, including genetic factors, allergens, various physical and chemical factors, mental and emotional factors, etc. They are described as follows: 1. Genetic factors The intrinsic factor of allergic diseases is the genetic variation, and its occurrence is related to family history of allergy. The disease is less likely to occur in families where both parents have no history of allergic diseases. According to statistics, the incidence of allergic diseases in children of two parents with allergic diseases is 70%. The incidence of the disease in their children is around 70%. If one parent has a significant allergy, the incidence of their children is about 50%. This genetic quality is called atopic quality. Studies have shown that the genetic variant is located on the long arm of the q segment of the 11th chromosome pair in the maternal line. 2. Allergens, also known as allergens, are macromolecular substances that stimulate the body to produce antibodies or sensitize, which should have two basic characteristics: one is to cause an antibody or cellular immune response, and the other is to specifically interact with antibodies or sensitized lymphocytes. The antigens that can cause allergy in humans are lipid-like or polysaccharides in addition to proteins. Allergens are widely present in the air and food. 2. 1, inhalation allergens are important allergens that induce asthma, allergic skin disease, allergic rhinitis, can be dispersed in the indoor and outdoor air, with the inhalation of the respiratory tract caused by allergy, including pollen, dust mites, fungi, certain pets (such as dogs, cats) fur and excrement, and even a variety of insect scales, debris, etc.. 2.1.1, pollen pollen can be allergenic components are mainly proteins, the vast majority of allergenic pollen are wind-borne flowers, pollen volume, small size, light weight, wide dispersal range, there is a clear regional and seasonal, such as the summer and autumn in the northern region of Penny’s pollen, ragweed pollen can cause allergic rhinoconjunctivitis, skin allergies and even allergic asthma. 2.1.2, dust mites Dust mites like to live in a warm, humid environment, there are about 50,000 species of mites in nature, but only a few are related to allergies, including house dust mites, dust mites, dust mites, etc. The mite’s body and molting skin, and even its excrement are antigenic. Human skin debris and grain dust are ideal food for dust mites, so there are often dust mites in large numbers on house dust, mattress dust and grain dust. 2.1.3, Fungi Fungi are a class of lower plants, their fungal robe and mycelium are antigenic, but the robe is more allergenic, and fungi are easy to breed in warm and humid areas and basements, warehouses and other places. 2.1.4, pet fur and excrement certain pets such as dogs, cats hair loss, debris and excrement can induce allergic dermatitis or asthma. 2.1.5, other more common allergens in the air include cigarette smoke, cockroach excrement, insect scales, hairs, cotton wool, feathers, etc. 2.2. Food Strictly speaking, except for glucose and sodium chloride, any food can be an allergen. The main foods that cause allergies include the following: 1. fish, shrimp, crab, clam and other seafood or aquatic products; 2. milk, eggs, meat, etc.; 3. mushrooms, rice vinegar, beer and other fungus-rich foods; 4. beans, peanuts, sesame, pistachios, almonds, cashews, etc.; 5. tomatoes, peaches , pineapple, grapes, strawberries, apples, cucumbers and other raw foods; 6, rare special foods, such as fried ants, silkworm flies, etc.; 7, alcohol, mustard, pepper and other irritating foods. For sensitive people, even if the amount of ingestion is very small, it can cause serious symptoms, but most patients have a positive relationship between symptoms and the amount of ingestion, that is, the more ingestion, the heavier the reaction. Symptoms can only occur when certain food antigens enter the body in a certain amount. After an attack, the body is temporarily depleted of allergic antibodies combined with antigens, and the symptoms can disappear for a period of time, but later, when a certain amount is accumulated, the allergic reaction will be triggered again. Some drugs are prone to cause allergic reactions, such as serum preparations, penicillin, sulfonamides, aspirin and procaine, etc. Generally speaking, organic drugs are more likely to cause allergic reactions than inorganic drugs, especially protein drugs, but heavy metals and iodides in inorganic drugs are also more likely to cause allergic reactions. Synthetic drugs are also more likely to cause allergic reactions than natural drugs. The only thing that determines the allergenicity of a drug is a specific chemical structure in the drug, i.e., a decision cluster. The allergenicity of drugs with the same decision cluster is also similar, which is a cross-allergy phenomenon of drugs. The method of drug administration has a great relationship with the occurrence of drug allergy. Local administration, subcutaneous or intramuscular injection, and intravenous drip are prone to cause allergic reactions. Among them, intravenous drug administration is most likely to cause allergy. 3, non-specific factors The rapidly changing human environment and various physical and chemical irritants are the main reasons for the rise of allergic diseases in recent times, and are particularly common in skin allergic diseases. In almost half of the patients, the onset and aggravation of lesions are related to certain physicochemical factors. 3. 1, physical factors such as cold, heat, pressure, sunlight exposure, exercise and other common physical factors, most people believe that the physical factors listed above can act directly on the skin, respiratory mucosa and other lesion sites to cause the onset of disease, some people also believe that it is through the role of nerve reflexes. 3. 2. Chemical factors With the development of industry, about 2,000 kinds of new chemical products are introduced every year, and these products penetrate into human’s clothing, food, housing and transportation, and the health problems caused by allergies are becoming more and more serious. 3. 2. 1, the presence of chemical allergens in food are mainly food additives, preservatives, flavoring agents, food coloring, such as tartaric yellow, salicylate. , MSG (monosodium glutamate), sulfites . , pesticides, herbicides, anti-mold agents, food packaging such as plastic. 3. 2. 2, the presence of chemical allergens in the air is mainly petrochemical products, from automobile exhaust, power plants, oil refineries, causing indoor air chemical pollution are gas, coal combustion CO, C02, SO2, etc., paint, coatings, decoration materials and other volatile compounds such as formaldehyde and benzene can induce respiratory allergies. Nickel alloy chrome-plated watch bands, necklaces, clothespins, etc. can cause contact dermatitis. 3. 3, other factors such as mental stimulation, excessive fatigue, infection, climate change, endocrine changes, nutritional disorders, etc. can cause the occurrence of allergic diseases. Such as clinical work found that some students in the examination before the nervous review, laid-off workers mental anxiety and depression can cause zun measles attack. Menstruation, pregnancy and other endocrine changes can also occur asthma. In short, the occurrence of allergic diseases is subject to the role of several factors, of which the exposure to allergens is the most important, so the prevention of allergens is the key to the treatment of allergic diseases. If allergens are identified and avoided, the disease can be reduced or even cured without medication, so preventive measures have both therapeutic significance. For several common food allergies such as cow’s milk, goat’s milk or soy milk can be tried instead. Since allergic factors are complex and many allergic factors are difficult to avoid, such as pollen, dust mites and fungi, which exist in large quantities in indoor and outdoor air, specific immunotherapy (desensitization) can be adopted, which has both preventive and therapeutic significance.