A previously healthy man in his 30s presented with spontaneous bruising, epistaxis, and haematuria. Acute promyelocytic leukemia (APML) was diagnosed by bone marrow aspirate morphology, immunophenotyping, and detection of the bcr1 variant of the PML-RARα fusion transcript in peripheral blood. He was commenced on treatment with the PETHEMA LPA 20051 protocol consisting of all-trans retinoic acid (ATRA) and idarubicin, an anthracycline based chemotherapy. Dexamethasone was prescribed to reduce the risk of ATRA syndrome, a potentially life threatening complication seen in these patients and characterized by fever, pulmonary infiltrates, hypotension, and leucocytosis.