I. Etiology and classification: contact dermatitis caused by cosmetics is called cosmetic dermatitis, according to the cause of irritant dermatitis and allergic dermatitis. The former is caused by strong irritation of the skin mucosa, generally in contact with cosmetics can be a few minutes after the onset, the latter is caused by skin allergy, metamorphosis, generally in contact with cosmetics 4-25 days after the onset of type IV delayed metamorphosis. Clinical manifestations: Due to the nature, concentration, and contact mode of the exposed material, the shape, scope, and severity of the lesions are also different. Generally in the contact area can be seen clearly bounded edematous erythema, the surface may have scattered red papules, serious cases can occur blisters, blisters, blisters can be broken to form a vesicular surface. The former has a single rash, while the latter has a polymorphic rash with unclear boundaries and a long disease duration, and a negative patch test. The diagnosis of laboratory product dermatitis is based on the following principles: 1. There must be a clear history of cosmetic exposure before the onset of the disease. 2, the primary site of skin lesions is the use of the cosmetic site. 3. Exclude non-cosmetic-induced dermatoses. 4. If necessary, perform patch test of the suspected cosmetics. V. Treatment principles: 1. Discontinue the use of cosmetics suspected of causing disease; 2. Treat symptomatically according to the clinical type and condition according to the treatment principles of general dermatological diseases; 3. Avoid re-exposure to explicitly disease-causing substances.