Background:

Wiskott–Aldrich syndrome (WAS) is a rare X-linked primary immunodeficiency characterized by the triad of microthrombocytopenia, eczema, and recurrent infections. Early manifestations are frequently misdiagnosed as immune thrombocytopenic purpura (ITP), resulting in delayed definitive diagnosis and management. Recognition of persistently reduced mean platelet volume (MPV), particularly in association with chronic eczema, is critical for early and accurate diagnosis.

Case Presentation:

We report a 6-year-old boy who initially presented at 9 months of age with recurrent febrile episodes and spontaneous bleeding manifestations, including epistaxis, hematemesis, hematochezia, petechiae, and ecchymoses. Laboratory evaluation revealed persistent thrombocytopenia with markedly reduced MPV (<5 fL). Bone marrow examination demonstrated normocellular marrow with increased megakaryocytes, leading to an initial diagnosis of ITP and treatment with corticosteroids and intravenous immunoglobulin, resulting in only transient improvement. Over time, he developed progressive, treatment-refractory eczematous dermatitis with hemorrhagic features, recurrent infections, and failure to thrive. Serial hematologic assessments consistently demonstrated microthrombocytopenia, prompting evaluation for an inherited thrombocytopenic disorder. Targeted next-generation sequencing identified a hemizygous pathogenic c.257G>A (p.Arg86His) variant in the WAS gene, confirming classical WAS. He received supportive dermatologic and hematologic management and was referred for hematopoietic stem cell transplantation (HSCT); however, transplantation was deferred due to financial constraints.

Conclusion:

Persistent microthrombocytopenia with reduced MPV in male infants, particularly when accompanied by chronic eczema and recurrent infections, should prompt evaluation for Wiskott–Aldrich syndrome. Early recognition through careful interpretation of platelet indices and dermatologic assessment is essential to avoid misdiagnosis as ITP and to facilitate timely molecular confirmation and referral for definitive therapy. Heightened multidisciplinary awareness is essential to reduce diagnostic delay and optimize long-term outcomes.