A 11-year-old boy with Blastocystis hominis infection, presents as immune thrombocytopenia.

Background: Some causes of first-line treatment failure for ITP are often closely related to infections. But parasitic infections are rarely mentioned and easily overlooked. The case is the first to describe a boy with immune thrombocytopenia associated with blastocystis hominis. Case presentation: The case involved a boy presenting with bleeding skin spots and ecchymosis and accompanied by intermittent epigastric pain and constipation. After a series of complete examinations, the platelet count was found to be decreased to 13 × 109/L and immune thrombocytopenia was diagnosed. After first-line treatment with gamma globulin and prednisolone, the thrombocytopenia remained unchanged. Blastocystis hominis was subsequently found in the patient's stool and then the treatment of metronidazole was provided. One week later, the patient's thrombocytopenia was completely relieved. He was followed up for six months and was found to have recovered well. Conclusions: The screening for potential predisposing factors is very important for immune thrombocytopenia patients with poor response to first-line treatment, and the best treatment strategy should include the management of potential diseases. [ABSTRACT FROM AUTHOR]