Stem Cell Steal After Intravenous Iron: A Case of Transient Thrombocytopenia in Severe Iron Deficiency Anaemia

Iron-deficiency anaemia (IDA) commonly presents with reactive thrombocytosis. A less recognized, paradoxical decline in platelets may occur shortly after iron repletion. This phenomenon is most notably seen with intravenous (IV) formulations and termed the platelet steal effect.

We describe a 68-year-old man with severe IDA (haemoglobin 6.6 g/dl; mean corpuscular volume 53.4 fl; ferritin 8.7 ng/ml; iron saturation 3.4%) who developed marked thrombocytopenia after initiation of IV iron. The platelet count trended down from 290 ×10³/μl on admission to a nadir of 39 ×10³/μl by hospital day 5 without bleeding. Other causes of thrombocytopenia were systematically excluded. Iron therapy was continued and transitioned to oral supplementation; platelets stabilized by day 10 and recovered thereafter in parallel with haemoglobin improvement.

Transient thrombocytopenia following iron repletion is likely under-recognized. Awareness of its timing and benign course may prevent unnecessary testing or interruption of definitive IDA therapy.

Transient thrombocytopenia may occur shortly after intravenous iron repletion in severe iron deficiency anaemia, despite the usual association with thrombocytosis.The "stem cell steal" phenomenon reflects a temporary shift of bone marrow progenitors toward erythropoiesis once iron becomes available.Recognizing this benign, self-limiting response prevents unnecessary investigations or interruption of essential iron therapy.