Allergy is a kind of metamorphic reaction of the organism, an abnormal reaction of the person to normal substances (allergens), which occurs only when allergens come into contact with allergic people, and there are hundreds of allergens such as pollen, dust, allogeneic proteins, chemical substances, ultraviolet rays, etc. In the process of allergic reactions, allergic mediators play a direct role. Allergens are the external cause of allergic diseases, while low immunity and oxidative damage to mast cells and basophils by a large number of free radicals are the internal causes of allergy. Common skin allergy symptoms 1. Red, itchy, red and swollen skin in sterile condition, mostly seen in people with congenital skin fragility; 2. Easy to produce eczema whenever the seasons change, weak UV resistance, skin allergy to synthetic fabrics, overly concentrated perfumes, changes in water quality, etc. The causes of skin allergy roughly lie in the consumption of seafood, the use of or contact with substances containing metals, breathing air containing plant pollen and reactions to drugs or insects, etc.; 3. Various causes lead to capillary non-congestion, causing impaired blood circulation, which leads to skin allergy; 4. Skin allergy to certain cosmetics, no matter how advanced cosmetics and maintenance products are, they are no more than a mixture of colorants, oils and fragrances, alcohols and other materials. All kinds of pearl creams, ginseng creams and all kinds of medicated powders are just adding various medicated ingredients on top of coloring agents, oil and spices and alcohol. Research shows that the basic composition and fragrance substances of color cosmetics or maintenance products may lead to the discomfort of skin sensitivity. Causes of skin allergy The causes of skin allergy include two major aspects: intrinsic causes refer to the patient’s own allergic constitution, a factor that plays a leading role in the development of skin allergy. Allergens are the external causes of the development of allergic conditions, while low immunity of the body and oxidative destruction of mast cells and basophils by a large number of free radicals are the internal causes of the development of allergy. There are also many external causes. The specific ones are as follows: 1. Pollen: In the pollen spreading season, tiny pollen particles will be scattered in the air during the spreading process and will fly around with the air flow, and some of them will be inhaled and absorbed by the skin at the same time. 2. Dust: Dust allergy is an allergic reaction to microorganisms that live in dust and is the most common allergy. Dust allergy includes cotton fiber, fur and various fibers, animal fur and so on. 3, cosmetics: The most typical cosmetic allergy is fragrance allergy, and cosmetics containing alcohol such as astringent water will also produce some skin irritation. Others such as biochemical preservatives, fruit acids and so on can cause different stimuli to different skin. 4, food: common is seafood, mangoes, nuts food will cause allergies. 5, drugs: penicillin, sulfonamides, etc., may trigger skin allergies. 6, age: perhaps the growth of age is an important reason for skin sensitivity. Some people’s skin was not sensitive in previous years, but it has become sensitive in the past few years. This is because the surface of young healthy skin has a weak acidic sebum film that retains moisture to protect the skin from external aggressions, but as we age, this sebum film is not as healthy as before, so that some sensitive substances can easily invade the skin. 7, pets: sensitive skin is easily allergic to the fur of domestic pets and other allergic phenomena. The reason for this allergy due to pets is mainly due to the proteins secreted by the oil glands of dogs and cats. When pets lick their fur, these proteins get on the fur and are scattered into the air and attached to the human skin. 8, seasonal changes: due to a variety of environmental factors, the air scattered bacterial spores and pollen and other allergenic substances will be released in large quantities of almost all tissues throughout the body compounds – histamine, causing facial skin allergies. 9, temperature changes: the temperature is hot and cold, so that sensitive people facial redness, hot. 10, ultraviolet light: ultraviolet radiation causes facial skin allergy.