Does your daughter have Infection (infection would cause a fever)? Infections can cause a high or low platelet count. In children, an infection is often accompanied by a raised platelet count. This is thought to be due to the hormones, called cytokines, that are produced as part of the body's normal defense against infection.
Additionally, a high platelet count can happen for many reasons, but there are two basic processes involved. The cells within the bone marrow produce more platelets.
Less platelets are removed from the blood by the spleen.
Has she had an infection lately? An infection can cause the platelets to be elevated. Are they extremely high or just a little high?