The main reasons for children to gnaw their nails are personal habits, zinc deficiency, hypocalcemia and so on. 1. Personal habits, children like to imitate the behavior of adults or people around them, if the people around them like to gnaw their nails, some children may also appear this symptom, usually a normal reaction. 2. Zinc deficiency, if the child’s body zinc deficiency, may lead to loss of appetite, growth retardation, but also may appear omnivorous, so may produce nail chewing symptoms. 3. Hypocalcemia, if the child has hypocalcemia, it may lead to increased neuromuscular excitability, mental anomalies, and may produce abnormal behavior, appearing small children gnawing nails symptoms. If it is a normal reaction, generally do not need to be treated, but if it is caused by zinc deficiency, hypocalcemia and other problems, you need to consult a doctor in time for examination and treatment.