Pitfalls in the diagnosis of immune thrombocytopenic purpura in children: 4 case reports.

Acute idiopathic thrombocytopenic purpura is the most common cause of thrombocytopenia in childhood, and diagnosis of idiopathic thrombocytopenic purpura is made clinically based on the exclusion of other causes of thrombocytopenia. Patients with diverse causes of thrombocytopenia are sometimes erroneously diagnosed as having idiopathic thrombocytopenic purpura. However, for the prevention of misdiagnoses, careful inspection of peripheral blood smear is of utmost importance. This report presents 4 cases presumed as acute idiopathic thrombocytopenic purpura that were finally identified as pseudothrombocytopenia, inherited macrothrombocytopenia (MHY9 disorders) possibly Epstein syndrome, Bernard-Soulier syndrome, and drug-induced thrombocytopenia. They draw attention to the importance of platelet morphology to exclude inherited macrothrombocytopenia and history to exclude drug-induced thrombocytopenia. Better diagnostic approaches would be possible by the awareness of these relatively rare causes of isolated thrombocytopenia.