The causes of dry hair and serious hair loss include malnutrition, ringworm of the head, dry seborrheic dermatitis and so on. 1. malnutrition: for people with unbalanced dietary intake or combined with malignant tumors and other consumptive diseases, due to the lack of nutrients in the organism, so it will affect the normal growth of hair, so the patient will appear dry hair, hair loss performance. 2. Tinea capitis: for patients with fungal infection of the scalp, due to the adhesion of a large number of local scales, blocking the scalp follicles and thus interfering with the normal growth of hair, so there is a dry hair, hair loss performance, and patients are also accompanied by increased dandruff. 3. Dry seborrheic dermatitis: the cause is still unclear, mostly related to genetics, endocrine disorders, fatigue and other factors, the patient is more often manifested in the scalp with each other fusion of red papules, which are covered with greasy scales or yellow scabs, combined with the performance of hair dryness, hair loss. Hair dryness and hair loss may have other reasons, it is recommended that patients go to a regular hospital, clear cause of the disease under the guidance of the doctor active treatment, do not self-medication.