Children gnawing nails may be related to mental tension, anorexia, bad habits, etc., the specific analysis is as follows: 1. Mental tension: when the child is nervous, stress may unconsciously gnaw fingers, belong to the emotional response. 2. Ectophagy: small children long-term picky eaters, nutritional imbalance may cause zinc deficiency, causing ectophagy, can show abnormal behavior, gnawing fingers, eating soil, eating hair, etc.. 3. Bad habits: some children habitually bite their nails in life, often mouth their fingertips and bite their nails. Small children gnawing nails may also have a relationship with other reasons, it is recommended to go to the hospital in a timely manner for relevant examinations, clear causes of symptomatic treatment.