Extreme reactive thrombocytosis in a healthy 6 year-old child()

Thrombocytosis is usually found by chance in children. Reactive or secondary thrombocytosis is the more common form, with infectious diseases being the most prevalent cause of it. Regarding the number of platelets there are four degrees of thrombocytosis; in its extreme degree the number of platelets exceeds 1,000,000/mm(3). We describe a case of extreme reactive thrombocytosis in a healthy 6-year-old child. He required critical care admission for diagnosis and treatment (maximum number of platelets 7,283,000/mm(3)). We review the different causes of thrombocytosis in childhood, the differential diagnosis, and the available treatments in case of extreme thrombocytosis.