Hair loss usually has no precursor symptoms. Hair loss includes androgenetic alopecia, patchy baldness, hair pulling fetish, etc. Symptoms of different types of hair loss vary, and usually there are symptoms of hair loss and hair thinning. 1. Androgenetic alopecia: This disease is related to heredity and androgen. Men will have hair loss symptoms on the forehead and top of the head, and the hairline will gradually move backward and the scalp will be exposed; women’s hair on the top of the head will be thinning and thinning, but the hairline will not move backward in general. 2. Spot baldness: this disease is mainly manifested by the sudden appearance of round or oval areas of hair loss on the scalp, which is usually self-limiting and related to mental and autoimmune factors. 3. Hair pulling fetish: this disease is mainly caused by the psychological effect of the patient, after pulling out the hair will make the psychological pleasure and relaxation, the patient’s scalp will appear in different sizes and shapes of hair loss areas. After the symptoms of hair loss appear, it is recommended to go to the hospital in time for treatment.