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Red Man Syndrome — SCE Infectious Diseases MCQ

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EasyAntimicrobial StewardshipRed Man SyndromeSCE Infectious Diseases

A 60-year-old man is started on IV Vancomycin for MRSA bacteraemia. On day 4, he develops a widespread erythematous rash affecting the face, neck, and upper trunk. He is tachycardic but blood pressure is maintained. The rash appeared 30 minutes after the infusion started. What is the most likely diagnosis?

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Correct answer: E — Red man syndrome (Vancomycin infusion-related histamine release)

Red man syndrome (RMS) is a histamine-mediated infusion reaction to Vancomycin, not a true allergy. It presents with erythematous flushing of the face, neck, and upper trunk, sometimes with pruritus and hypotension. It is caused by rapid infusion rather than immune-mediated hypersensitivity. Management includes slowing the infusion rate, pre-medication with antihistamines (Chlorphenamine), and re-challenging at a slower rate. Vancomycin does not need to be permanently discontinued. True IgE-mediated allergy to Vancomycin is rare.

Reference: BNF 2024 – Vancomycin; BSAC 2023 – Antibiotic adverse effects