Uneven nails may be related to calcium deficiency, iron deficiency anemia and onychomycosis. 1. Calcium deficiency: uneven nails of children may be related to calcium deficiency. Children who are picky eaters or partial eaters and eat too little meat may lack calcium, which may cause uneven nails. 2. Iron deficiency anemia: Iron deficiency anemia may cause abnormal nail shape and uneven nails. 3. Ringworm: Fungal infection of the nails may cause unevenness and thickening of the nails. There may be other reasons for uneven nails, so we suggest that you go to the hospital in time, complete the examination to clarify the cause of the disease, and then treat the disease under the guidance of the doctor.