The causes of elevated platelets in children may be nutritional anemia, inflammatory infections and hematological diseases. 1. Nutritional anemia: this condition is relatively common, which will cause the body’s bone marrow hematopoiesis by reactive stimulation and cause platelet reactive proliferation, resulting in increased platelet index. 2. Inflammatory factors: inflammatory infections can also cause platelet elevation. 3. Hematological diseases: for example, abnormal hematopoietic function of the blood system, including myeloproliferative neoplasm or primary thrombocythemia, etc., may cause platelet elevation. Parents are advised to bring their children to regular hospitals to receive systematic examination, and according to the examination results, treat their children under the guidance of specialists, so as to avoid affecting the growth and development of their children.