Cosmetics are substances applied to human skin or mucous membranes by applying, spraying or other similar methods for cleaning, beautifying, adding charm, improving body surface morphology, correcting body surface odor or acting as a protective function, such as bath lotion, shampoo, soap, etc. are all cosmetics. The diagnostic criteria for cosmetic allergy are as follows: 1. a history of contact with cosmetics before the onset of the disease (not necessarily applied by oneself); 2. the site of onset is relatively consistent with the cosmetic contact site, but can also extend to the surrounding and distant parts; 3. the onset of the disease is consistent with the onset of allergic contact dermatitis; 4. it subsides or improves after discontinuing the use of the suspected cosmetics; 5. the lesions appear to be eczema dermatitis-like; 6. other known causes of dermatitis are excluded; 7. dermatitis; 7. If the patient is able to continue using the cosmetic products to which he/she feels a reaction, then exclude. If the above criteria are met, the diagnosis of suspected cosmetic allergy is made. If the following criteria are added: 1. positive application test; 2. positive patch test for suspected cosmetics; 3. positive repeated open application test. Then the diagnosis of cosmetic allergy can be confirmed.