Severe hair loss may be caused by frequent perming and coloring, seborrheic alopecia, baldness and other reasons. 1. Frequent perming and dyeing: the chemical composition in the perming and washing solution will cause damage to the hair root, frequent perming and washing will lead to a large amount of hair loss, when stopping perming and dyeing for a period of time or do a good job of hair care, the situation of hair loss may be improved. 2. Seborrheic alopecia: Seborrheic alopecia is a progressive hair loss disease, which is mainly manifested in the frontal hairline backward, the hair on the top of the head progressive reduction, thinning and other symptoms, patients with severe hair loss may be caused by seborrheic alopecia. 3. Patchy baldness: Patchy baldness is a kind of limited patchy hair loss, the border of the hair loss area is clear, no scar, no inflammatory reaction, and its main manifestation is a sudden massive hair loss, the edge of the hair is loose, easy to pull out and other symptoms. In addition, malnutrition, endocrine disorders, hypothyroidism, postpartum alopecia, etc. may also cause severe hair loss. It is recommended that patients seek medical examination in time to clarify the cause of the disease and then carry out targeted treatment.