Hair loss is always the case, consider and physiological factors, malnutrition, seborrheic dermatitis, androgenetic alopecia and other factors. 1. Physiological factors: Physiological hair loss is the normal metabolism of human beings, the phenomenon of hair loss. The amount of hair loss per day within 100 is normal, no need to be too nervous, pay attention to adjust the diet, develop good habits can be. 2. Malnutrition: If the patient is often picky about food and partiality, the dietary intake of nutrients will be insufficient to supply the growth of hair, and then the symptoms of hair loss always occur. 3. Seborrheic dermatitis: seborrheic dermatitis mainly occurs in the head, face, chest and back, belonging to the common chronic inflammatory skin diseases, manifested as local erythematous rashes, the surface of the greasy scales or scabs, accompanied by itching symptoms, some patients will also have obvious hair loss performance. 4. Androgenetic alopecia: usually to the top of the forehead hair progressive reduction as the main symptom, men and women can occur, mainly and hereditary and androgen-related. There are other reasons for hair loss, so it is necessary to cooperate with the doctor to check and clarify the cause, and then do targeted treatment and therapy.