Children often bite fingernails may be related to psychological factors, trace element deficiency, other disease factors. 1. Psychological factors: when children have emotional tension, emotional needs are not satisfied, there may be anxiety, insecurity, and fear, leading to the phenomenon of children often biting fingernails. 2. Lack of micronutrients: If children usually have bad habits such as picky eating and partiality, it may lead to the lack of micronutrients in the body, such as zinc and iron deficiency, which may easily cause xenophagia and frequent fingernail biting. 3. Other disease factors: when the child suffers from Tourette’s syndrome, it may also lead to the child’s bad habit of biting fingernails often, and also accompanied by blinking, opening the mouth, shrugging shoulders and other small movements. Children often bite fingernails may also have other reasons, it is recommended to go to the hospital in a timely manner, improve the examination to determine the cause of the disease, under the guidance of the doctor to give targeted treatment or treatment.