Massive hair loss is usually caused by resting hair loss, neuropsychiatric factors, infectious factors, endocrine factors and so on. 1. Resting hair loss: under normal circumstances, people will lose about 50~100 hairs per day, because after the hair grows to a certain extent, it will enter the regression and resting phase, thus physiological shedding. 2. Neuropsychiatric factors: long-term frustration, depression, anxiety and other bad moods, can cause mental stress, a large number of hair loss. 3. Infectious factors: Head infection with fungus can trigger ringworm, resulting in massive hair loss, scalp itching and other phenomena. If the head is infected with bacteria, it can cause alopecia folliculitis, which leads to the appearance of yellowish-white pustules at the follicles of the scalp and is accompanied by a large amount of hair loss. 4. Endocrine factors: such as androgenetic alopecia, mostly occurring in adolescence, manifested as progressive hair loss and thinning hair, usually accompanied by increased oil secretion of the scalp. In addition, malnutrition and medication can also cause massive hair loss. It is recommended to go to the hospital in time to find out the cause of the disease and receive treatment as soon as possible.