Redness of the skin on the face may be caused by contact dermatitis, seborrheic dermatitis, capillary dilatation and other diseases. 1. Contact dermatitis: the cause of the disease is mainly related to the skin contact with textiles, cosmetics, leather products and other exogenous substances, stimulation of local allergic reactions. Patients will appear erythema, papules, blisters and other symptoms, accompanied by itching, swelling and pain, if the face suffers from contact dermatitis, may lead to redness of the skin on the face. 2. Seborrheic dermatitis: the etiology is not clear, may be related to infection, genetics, diet, immune dysfunction and other factors. Patients will appear localized diffuse erythema and covered with scales, which can be seen on the scalp, face, trunk and so on. 3. Capillary dilatation: the cause can be related to heredity, hormone, physical factors, trauma and other reasons. The main manifestation of the skin red spots, mottled, dotted, etc., mostly in the face. If there is redness of the skin on the face, it is recommended to go to a regular hospital for examination to clarify the cause.