Types of hair loss include patchy baldness, congenital alopecia, androgenetic alopecia, scarring alopecia, resting alopecia, etc. The causes of hair loss are related to the types, such as congenital factors. 1. Patchy baldness: Congenital factors: generally considered to be polygenic hereditary. Disorders of the nervous system: patients may have anxiety, tension, panic, etc. before and after the onset of the disease. Other diseases: foci of infection, endocrine disorders, etc. are triggers. 2. Congenital alopecia: it may be related to genetic factors. 3. Androgenetic alopecia: autosomal dominant, affected by gender and age. 4. Purpura alopecia: Inflammatory causes: the most common are discoid lupus erythematosus, nodular disease and folliculitis alopecia. Infection: can be secondary to bacterial and fungal infections. Physical or chemical injuries: such as mechanical trauma, ionizing radiation, burns, or strong acids and bases. Secondary to other diseases: skin tumors occurring on the scalp or limited scleroderma, etc. 5. Resting hair loss: Injury: such as pulling and other mechanical injuries. Infectious diseases: can be secondary to typhoid fever or pneumonia, etc. Drugs: can be caused by heparin, bicoumarin and so on. Chronic diseases: such as tuberculosis. Hair loss patients should go to the hospital in time, under the guidance of the doctor standardized treatment.