There are six types of alopecia areata, and the reason for the different typing is that the causes are different, such as congenital alopecia areata, androgenetic alopecia, patchy baldness, drug alopecia areata, resting alopecia areata, and endocrine alopecia areata. 1. Congenital alopecia: the cause is usually a genetic mutation, patients often have a family history, the typical symptoms are fine hair, dry, thinning and so on. 2. Androgenetic alopecia: the cause of the disease is usually genetic factors and abnormal androgen activity in the male body. Typical symptoms are hair loss from the center of the head, and most of the patients start to develop from puberty. 3. Patch baldness: the cause of the disease is usually mental factors, such as stress, life tired, etc. Typical symptoms are the sudden appearance of oval or round, clear boundaries, the number of varying, 1 ~ 10cm in diameter of the hair loss area. 4. Pharmacological alopecia: the cause of the disease is generally many drugs such as anticoagulants, anticancer drugs, etc. so that the keratinization process of the hair is disturbed or the hair matrix cell division is inhibited, the typical symptom is the emergence of alopecia or temporary hair loss. 5. Resting alopecia: the cause is generally hair growth cycle disorders caused by diffuse baldness, typical symptoms are postpartum alopecia, post-fever alopecia, neonatal alopecia and so on. 6. Endocrine alopecia: the cause is usually hypothyroidism, and the typical symptoms are hair thinning, slow growth, and lack of luster. If you have symptoms of hair loss, please go to the hospital as soon as possible, listen to the doctor’s diagnosis, and make individualized diagnosis and treatment plan, so as to avoid delaying the condition and causing adverse consequences.