Dandruff is a normal metabolic product of the human body, which can also be seen in seborrheic dermatitis, psoriasis and ringworm and other diseases, and can be removed through general treatment, drug treatment and other methods. 1. Physiological reasons: dandruff is a normal metabolic product of human epidermis, as long as the dandruff is not particularly serious, can be removed through the correct way of washing hair, it is recommended to wash your head with lukewarm water once every 2-3 days, massage your scalp with your fingertips, and don’t pick it out with your nails to avoid damaging the scalp. 2. Pathological causes (1) Seborrheic dermatitis: in addition to the abnormal increase of dandruff, it can also be manifested as excessive oil secretion, which can be used externally with ketoconazole, selenium sulfide lotion or tacrolimus cream under the guidance of doctor. (2) Psoriasis: If the skin also has silvery-white scales, right itching and burning sensation, psoriasis is suspected. Usually topical tazarotene gel, carbotriol cream, etc. can be used. (3) Tinea capitis: If accompanied by a small amount of hair loss, hair breakage, black spots at the mouth of hair follicles, etc., tinea capitis is suspected, and antifungal treatment is the mainstay of treatment, including terbinafine and itraconazole. If the dandruff is excessive and can not be removed, do not self-medication, it is recommended to seek timely medical treatment, and then targeted treatment.