Mouth and face dry skin may be physiological reasons such as dry skin, etc., but also may be pathological reasons such as fungal infection, psoriasis, seborrheic dermatitis, etc.. 1. Physiological reasons Dry climate in autumn and winter, usually do not pay attention to moisturizing and so on can lead to skin moisture loss or lack of moisture, at this time there can be dry skin peeling. This is a common physiological phenomenon, should pay attention to daily moisturizing care. 2. Pathological reasons (1) Fungal infection: After skin infection with Malassezia, lichen planus may appear, which may be manifested as dry and white flakes on the face. It can be treated with topical antifungal drugs, such as clotrimazole ointment, miconazole cream and other drugs. (2) Psoriasis: the cause of psoriasis is not clear, and it may be caused by the interaction of genetic and environmental factors. The main manifestations are recurrent scaly erythema, papules and plaques. It is mainly treated with topical glucocorticoids and other treatments, and oral methotrexate and retinoids can be taken if the symptoms are severe. (3) Seborrheic dermatitis: the cause of seborrheic dermatitis is not yet clear, and it may be related to the colonization of Malassezia bacteria and impaired skin barrier function. There may be localized redness of the skin, flaking, dry white flakes on the face and other manifestations, which may be accompanied by itching. It can be treated with local topical tacrolimus ointment and other medications. There are many reasons why the mouth and face are dry and flaky, and after excluding the physiological reasons, you should go to the hospital in time for standardized diagnosis and treatment.