Allergy is an abnormal reaction of the body to normal substances (allergens). Allergic dermatitis is an abnormal inflammatory reaction of the skin to external stimuli. Allergy occurs when allergens come into contact with the allergic population. There are hundreds of allergens such as pollen, dust, foreign proteins, chemicals, ultraviolet rays, etc., and some allergies cannot even be detected. The incidence of allergic diseases accounts for about 20% of the population and occurs in all ages from newborns to middle-aged and elderly people. There is no obvious gender characteristic, but there is a clear hereditary characteristic. Why does skin allergy occur? 1, age, the skin secretion function degradation, the skin in the years under the wear and tear, will become thinner, its protective layer function is also weakened. 2, long-term exposure to sunlight or air pollution in the environment, smoke, ash, ultraviolet light UVA and UVB, as well as infrared rays, will damage the skin, because they produce free ions can destroy the skin’s lipid protective layer. 3, poor quality cosmetics or improper drug damage. 4, physiological factors, stress, nervousness and emotional depression, will weaken the skin’s natural resistance, resulting in its self-repair function is also slowed down. 5, in the face of weather changes, the skin also needs additional adaptation, for example, in cold weather, if the skin is not adequately moisturized, it will be easily damaged. 6, some skin care products in the ingredients such as preservatives, dyes, emulsifiers and fragrances and other additives, may make the skin become sensitive. 7, idiosyncratic body. What contingency measures should be taken for skin sensitivity? 1, should stop using all cosmetics, so that the skin has a buffer time, if you usually use hypoallergenic skin care products, you can continue to use; if it is the first time or occasionally sensitive phenomenon, and do not use hypoallergenic weekdays, then we must choose to have an anti-inflammatory, calming effect of the skin care products skin protection. Cream, used after washing the face with water. If the phenomenon of persistent redness, we must go to the hospital for desensitization treatment, but also cotton or gauze fully moistened with injectable saline, applied to the sensitive parts of the face, this injection of saline, high security, good penetration, with the swelling, redness, stabilization of the skin’s function, in general, a few days later, the redness and swelling phenomenon will be eliminated. 2, strengthen the skin’s resistance is also an effective basic countermeasures, such as adequate sleep, a balanced diet, emotional harmony, away from polluted environments and allergens, reduce skin irritation. Slight sensitivity as long as the appropriate treatment, will soon be restored, serious cases should quickly consult a doctor. 3, do not take medication without authorization. Without the diagnosis of dermatologist, do not buy hormone ointment to the drugstore to use, which is harmful to the skin. Because it is effective in suppressing inflammation, but long-term use will produce side effects and jeopardize health. How to take care of overly sensitive skin? 1. Keep away from allergens. Because the symptoms of allergy will always be there, you can only take precautions at all times to avoid contact with allergens that may cause allergy. 2, to clearly understand the skin care products you use and their usage. Avoid substances that are potent, overactive and may cause skin irritation. Excessive and inappropriate use of strong cleansing products can damage the skin’s surface layer of natural protective tissues; too active, will make the blood circulation accelerated cosmetics can also irritate the skin, causing damage. Do not use soap cleansers such as medicated soap to wash your face, because the surfactants make the break down of keratin master, to be strongly avoided. It is best to use emulsions, or non-soap soaps that can regulate pH and adapt to the skin. Products such as scrubs and exfoliants should be avoided. Use a simple cleansing toning moisturizing program. 3, pay attention to the use of sunscreen products. Sensitive skin skin layer is thin, the ultraviolet rays have no defense ability, easy to aging, so after rubbing on the basic maintenance products as isolation, and then use sunscreen will be better, but the ingredients of sunscreen is also easy to cause irritation of one of the factors, so it is best not to apply directly on the skin surface. Some manufacturers have introduced sunscreens that contain fewer chemical ingredients and have physical ingredients that cause relatively less skin irritation. At the same time to avoid excessive exposure to the sun, because ultraviolet penetration is particularly strong, often exposure to the sun will make the skin thinner, more prone to stimulation. 4, careful use of cosmetics. For people with sensitive skin, it is best not to replace the usual cosmetics, if you want to use new cosmetics, you should first do a skin test, the method is to be used to apply cosmetics on the inside of the wrist where the skin is more delicate, stay overnight or 2-3 days to observe the reaction, if there is an abnormal reaction, such as inflammation, redness, blotchy rash, etc., it is necessary to avoid the use of the cosmetic. 5, sensitive skin, usually should use warm water to wash the skin, in the spring pollen flying areas, to minimize the outing, to avoid causing pollen dermatitis, can be used in the morning and evening moisturizing cream to keep the skin moisturized, to prevent the skin from drying, flaking. 6, in the diet, to eat more fresh fruits and vegetables, diet should be balanced, the best including a large number of fruits and vegetables rich in vitamin C, any food containing vitamin B. Drink a lot of water, in addition to a variety of benefits, it is more in the body to moisturize the skin. Usually make some homemade nutritional masks, such as cucumber juice mask, loofah juice mask, egg white honey mask, etc., in order to gradually improve the skin condition, to obtain skin fitness. 7, accompanied by clothing to be rinsed clean, residual detergent in the clothing towels may stimulate the skin. 8, sleep with beauty effects, eight hours a day of adequate sleep, is any skin care products can not be replaced. 9, exercise can improve blood circulation, enhance skin resistance, into the best state.