With the massive use of cosmetics, skin diseases caused by cosmetics have increased in large numbers, and skin allergy is one of the most common ones. In order to prevent skin allergies, cosmetics should not be applied directly to the face after purchase, but the skin allergy test must be done first in order to prevent adverse consequences after extensive use and to ensure safety in use. Whenever you replace a cosmetic (skin care product), as long as it is the first time you use the brand, you should conduct an allergy test, which can be done in small amounts behind the ear first, especially for people with allergic skin, to avoid unnecessary consequences. Causes of allergies Skin allergies are caused by certain ingredients in cosmetics that stimulate skin cells, causing skin cells to react to allergies. Many of the cosmetics currently sold on the market are made with chemical ingredients, and additives such as emulsifiers, fragrances, colors, fungicides, and preservatives may cause allergies to the skin. At present, among the patients with facial allergy in hospitals, according to my experience mask allergy is more common. The test results of cosmetic-related ingredients in Yunnan Province show that the qualified rate of whitening cosmetics is 52.4%, while the qualified rate of spot-removing cosmetics is only 39.5%, and the failed items are mainly excessive mercury. When choosing cosmetics, you should pay attention to: understand your skin type and choose cosmetics that are compatible with your skin; choose cosmetics that do not contain lead and mercury to prevent chronic poisoning after long-term use; do not use cosmetics that have been stored for too long to prevent the oxidation and decomposition of nutrients in cosmetics, pollution from outside during use, and the proliferation of bacteria or mold and other microorganisms that cause It is best to use a fixed brand of products, because frequent replacement of cosmetics, the skin will be constantly exposed to new stimuli, accelerating the decay of skin cells, resulting in skin aging and pigmentation abnormalities; be sure not to choose products that do not indicate the composition of cosmetics, because if the ingredients are not marked, it can simply be considered a shoddy product. Skin test For sensitive faces, it is best to do a skin allergy test before buying cosmetics! The skin allergy test method for cosmetics is very simple, namely the cosmetic ingredient patch test. After knowing what ingredients you are allergic to, you can choose cosmetics that do not contain allergic ingredients. The top 3 allergic ingredients in the positive rate of the patch test for facial dermatitis at Xijing Hospital are: sorbitan sesquioleate, carlson CG, and amoxicillin. Of course, if you don’t have time to come to the hospital or have already purchased cosmetics, you can simply apply the cosmetics to be used behind your ears for three consecutive days, and if skin symptoms such as itching or erythema occur, you can assume that you are allergic to this cosmetic. Solution In case of cosmetic contact dermatitis, you should stop using all types of cosmetics and go to the hospital for diagnosis and control of the disease. Of course, another point is that it is easy to fall into the misconception of using creams as soon as allergies appear; when cosmetic allergies recur for a long time, long-term topical hormonal creams can lead to hormone-dependent dermatitis; the best way is to avoid contact with the allergen. Reaction classification If the use of cosmetics can cause allergies, what are the general skin reactions? In general, skin diseases caused by cosmetics include: contact dermatitis (irritant or allergic), orofacial dermatitis, photosensitivity dermatitis, cosmetic acne, hormone-dependent dermatitis, and hyperpigmentation; there are also cosmetic urticaria, hair damage, and nail damage. Irritation Synthetic chemicals in cosmetics such as pigments and fragrances, ethanol can directly stimulate the skin after contact with the skin causing erythema, itching, burning sensation, etc. Allergic reactions For some people with allergic qualities, the use of certain cosmetics, such as permanent dyes in lipsticks, p-phenylenediamine in hair dyes, and cosmetics containing various fragrances and preservatives, can cause allergic contact dermatitis. High concentrations of perfume, deodorant, hair cream on some allergic body can cause various allergic reactions, cause cough, allergic rhinitis, conjunctivitis, hives, etc. Light-sensitive reactions Sandalwood oil, lemon oil, etc. are photosensitive substances, and cell damage and inflammation can occur in the skin when these cosmetics are applied under sunlight. Pigmentation Some cosmetics, such as pure jasmine oil, sandalwood oil, and geranium oil, can cause “pigmented cosmetic dermatitis” in some women: diffuse or patchy light brown pigmentation on the cheeks or forehead, sometimes with mild erythema or papules and an itchy sensation. Hormone-dependent dermatitis People with facial skin problems use hormone-containing cosmetics, which are used on the skin for a long time and form dependence. Illegal addition of hormone ingredients to drugs or non-drugs for the purpose of profiteering. (In 2008 the CDC tested cosmetics suspected of causing hormone dependent dermatitis for hormones and antibiotics and the detection rate was over 40%).