White spots on the fingernails of a 5-year-old child may be caused by trauma, or it may be due to anemia and other diseases. 1. trauma: if a 5-year-old child has recently suffered mechanical trauma to the fingernails, causing damage to the nails, the fingernails are prone to white spots. 2. Anemia: the pathogenesis of this disease is mainly related to insufficient or reduced red blood cell production, excessive destruction of red blood cells, blood loss, etc. It can be induced by unbalanced diet, viral infections and other factors. Some of the affected children will have white spots on their fingernails, and will also have headaches, pale skin, dizziness and other symptoms. There are more causes of white spots on finger nails of 5-year-old children, such as fungal infection, and they need to go to the hospital and do relevant examinations to clarify the specific causes.