Abnormal platelet function in a patient with transient eosinophilia: A case-based discussion

Eosinophilia is commonly associated with parasitic infections, allergic disorders and haematological conditions. Although bleeding in patients with eosinophilia is rare, platelet dysfunction may contribute, even when platelet counts are normal. We report the case of a 7-year-old boy with glucose-6-phosphate dehydrogenase deficiency who presented with recurrent spontaneous bruising over 6 months. Physical examination revealed multiple ecchymoses over the lower limbs, with no organomegaly or lymphadenopathy. Laboratory investigations revealed a normal platelet count, marked eosinophilia and prolonged bleeding time. Platelet function testing using whole blood impedance aggregometry (Chrono-Log) demonstrated reduced aggregation in response to multiple agonists, consistent with a selective impairment of aggregation to adenosine diphosphate and collagen. The patient was treated with anthelminthics, resulting in a significant reduction in the eosinophil count and resolution of bleeding symptoms. This case highlights that eosinophilia may be associated with acquired platelet dysfunction, even in the presence of normal platelet counts. Clinicians should consider platelet function testing in patients with unexplained bleeding and eosinophilia, as timely treatment of the underlying cause can lead to clinical improvement.