Fever, facial swelling and rash after starting allopurinol in a 70-year-old man

A 70-year-old man was admitted to hospital with a five-day history of fever, facial swelling and a widespread rash. He had been in good health until three weeks after starting allopurinol 100 mg once daily for gout, when he developed a pruritic rash on his trunk. One week later he developed fever and facial swelling. He had no cough, sore throat or joint pains. He had taken amlodipine 5 mg daily for hypertension for five years, metformin 500 mg twice daily for type 2 diabetes for three years, and atorvastatin 20 mg daily for hypercholesterolaemia for two years. On examination, his temperature was 38.8°C, blood pressure 145/85 mmHg, pulse 108 bpm, respiratory rate 20/min. He had bilateral facial oedema, a diffuse maculopapular rash over his trunk, arms and legs, and enlarged cervical lymph nodes. There were no oral lesions or jaundice. Investigations: haemoglobin 135 g/L, white cell count 14.5 × 10^9/L with eosinophils 2.8 × 10^9/L, platelets 210 × 10^9/L. Serum creatinine 95 µmol/L, urea 7.2 mmol/L. Liver tests: ALT 220 U/L, AST 190 U/L, alkaline phosphatase 320 U/L, bilirubin 58 µmol/L. Blood cultures were negative. Serology for Epstein-Barr virus, cytomegalovirus, hepatitis A, B and C, and HIV was negative. A chest radiograph showed no abnormality. Allopurinol was stopped on the day of admission. Over the next five days the fever subsided, the rash faded and the facial swelling resolved. Liver enzymes improved but remained elevated. He was not rechallenged with allopurinol.