Acetaminophen-associated secondary haemophagocytic syndrome in a trauma patient with possible non-steroidal anti-inflammatory drug hypersensitivity: A case report

Background Secondary haemophagocytic syndrome (HPS) is a rare but potentially life-threatening complication of drug hypersensitivity. We report secondary HPS developing in close temporal association with acetaminophen administration in a trauma patient with possible non-steroidal anti-inflammatory drug (NSAID) hypersensitivity. Case presentation A 24-year-old man with a severe crush injury to his hand developed urticaria after taking celecoxib and loxoprofen. Analgesia was switched to acetaminophen (400 mg). Administration of acetaminophen on days 32 and 33 after injury caused erythema, followed by a high fever (>40 °C), pancytopenia, liver dysfunction, elevated lactate dehydrogenase and hepatosplenomegaly on day 37. HPS was clinically diagnosed, supported by an HScore of 214 (estimated probability approximately 95%). Prednisolone at a dose of 30 mg per day produced a prompt recovery. Conclusion Acetaminophen, although not a classical NSAID, may be associated with severe systemic hypersensitivity including secondary HPS. Orthopaedic surgeons should consider this rare complication when patients develop hypersensitivity reactions to multiple analgesics.