The common reasons for hair splitting include physiological factors, nodular brittle hair disease, iron deficiency anemia and so on. 1. Physiological factors: If you usually eat an unbalanced diet, picky eating, anorexia, dieting, etc., resulting in a lack of nutrients in the body, affecting the supply of nutrients to the hair, the phenomenon of hair splitting; in addition, frequent perming and dyeing of the hair, hair bleaching, the use of poor-quality chemical products, etc., it is easy to damage the hair quality, the phenomenon of hair splitting. 2. Knotty Hair: This disease manifests itself as rope-like knots in the central or terminal portion of the hair, and the hair shaft is flexed and curled, irregular in shape, accompanied by dry, longitudinal cracks and increased brittleness of the hair, which manifests itself as symptoms of hair splitting and so on. 3. Nodular brittleness: this disease is mainly due to genetic metabolic diseases, nutritional deficiencies, developmental defects in the hair shaft or permed and dyed hair, inappropriate combing of the hair and other reasons, resulting in nodularity of the hair, fracture, split ends and other symptoms. 4. Hair pulling fetish: this disease is mainly related to psychoneurological factors, manifested as patients repeatedly pulling, twisting or pulling their own hair, resulting in hair loss, hair quality damage, hair splitting and other symptoms. It is recommended that if the patient can exclude physiological factors, it is best to go to the regular hospital dermatology consultation, follow the doctor’s instructions for a clear diagnosis, timely treatment, to avoid delaying the condition.