High platelets in children may lead to increased viscosity of the blood, which slows down blood circulation, resulting in lethargy, fatigue, dizziness, and lack of concentration in children, and can seriously lead to the formation of blood clots. Children with high platelet count should be treated according to the specific causes, the common clinical causes are dehydration, infection, immune diseases and myeloproliferative diseases, etc. 1. Dehydration: High platelet count in children is caused by insufficient body fluids and blood concentration. If you drink less water or suffer from gastrointestinal diseases, vomiting, diarrhea and other symptoms, resulting in more loss of body fluids, you are prone to dehydration, which leads to blood concentration and causes platelet hyperplasia. In this case, we should actively replenish water, and if necessary, carry out infusion therapy to relieve the platelet increase due to blood concentration; 2. Infection: If there are infectious diseases such as upper respiratory tract infection, pneumonia, sepsis, etc., due to the stimulation of toxins, the bone marrow proliferates vigorously, resulting in excessive platelet production, and the platelet count will also increase. Anti-infection treatment should be actively carried out, and a sufficient amount and course of sensitive antimicrobial therapy should be given. With the control of inflammation, platelets can also be reduced to normal; 3. Immune diseases: autoimmune diseases such as Kawasaki disease and juvenile idiopathic arthritis in children can also lead to increased platelets. Immune diseases should be actively treated through the use of non-steroidal anti-inflammatory drugs, immunosuppressants, etc., so that the increased platelets can be relieved; 4, myeloproliferative diseases: also seen in primary thrombocytosis, a myeloproliferative disease, often with genetic mutations in the body, antiplatelet therapy such as hydroxyurea and aspirin should be given under the guidance of a doctor to avoid thrombosis.