Acute pure red cell aplasia associated with allopurinol therapy

Several investigators have reported patients with acute pure red cell aplasia (PRCA) caused by anticonvulsants, antibiotics, or antithyroid agents. Allopurinol is known to be a causative agent of aplastic anemia, but there have been few reports of acute PRCA induced by allopurinol. We describe here a 15-year-old boy who suffered from anemia 6 weeks after initiation of allopurinol therapy; his anemia immediately improved after cessation of the drug. His bone marrow showed severe erythroid hypoplasia with a myeloid/erythroid ratio of 18.6 and low expression of glycophorin A detected on cell-surface antigen analysis. No morphological abnormalities were observed in myeloid series and megakaryocytes. The prolonged plasma iron disappearance rate and the decreased plasma iron turnover rate also indicated erythroid hypoplasia. He had been free from any infections, including parvovirus B19, before manifestation of PRCA. Taken together, these results suggest a diagnosis of acute PRCA. This side effect of allopurinol should be taken into consideration.