Hair loss can be caused by congenital factors, physical factors, endocrine disorders, skin diseases, infections, systemic diseases, etc. It is recommended to consult a doctor in time. 1. Congenital factors: such as dysplasia, congenital alopecia, abnormalities in hair shaft structure, etc. 2. Physical factors: such as burns, mechanical injuries, X-ray irradiation, long-term friction. 3. Endocrine disorders: such as postpartum alopecia, menopausal and androgenic alopecia, hypothyroidism, etc. Patients may also be accompanied by fatigue, fear of cold, low perspiration, slow reaction, loss of appetite and other symptoms. 4. Skin diseases: such as limited scleroderma, discoid lupus erythematosus, lichen planus, etc., patients may also be accompanied by patchy rash, pimples, vesicles on the lower lip, oral damage and other uncomfortable symptoms. 5. Infections: including various bacterial and fungal infections, such as leprosy bacillus, dermatophytes and so on. 6. Systemic diseases: such as anemia, malnutrition, tuberculosis, cirrhosis and other chronic diseases, can also lead to hair loss. Patients with hair loss symptoms, persistent non-relief or more serious symptoms, should consult a doctor in a timely manner, follow the doctor’s instructions for appropriate treatment, do not blindly judge on their own, so as not to delay the condition.