The reason for the dandruff is not clear, but it may be related to pathogenic infection, sebaceous gland overproduction and genetic factors, and can be treated with topical ketoconazole hair lotion. 2. The actual cause is unknown and may be related to sebaceous gland metabolic abnormalities, infectious factors, dietary factors, and external stimuli, such as inappropriate shampoo, etc. Usually you can choose to use selenium disulfide lotion topically, and you can take vitamin B2 and vitamin B6 orally. 3, consider the possibility of scalp psoriasis, psoriasis belongs to chronic inflammatory scaly skin disease, and its pathogenesis is related to immune factors, neuropsychiatric factors, and genetic factors, etc. Usually you can choose to use topical carbotriol application and other treatments.