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Penicillin Allergy Delabelling — RACP Adult Medicine MCQ

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ModerateClinical PharmacologyPenicillin Allergy DelabellingRACP Adult Medicine

A 58-year-old man with a penicillin allergy (childhood rash, unclear details) requires treatment for Streptococcus pneumoniae bacteraemia. What is the recommended approach?

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Correct answer: BTreat with moxifloxacin

Penicillin allergy is over-reported; >90% of patients labelled penicillin-allergic can safely receive penicillin after formal testing. Australian antimicrobial stewardship guidelines strongly recommend penicillin allergy delabelling. A distant childhood rash with unclear details is very unlikely to represent true IgE-mediated allergy. Formal assessment (skin testing ± oral challenge) should be performed when feasible. In the acute setting, many 'penicillin-allergic' patients can safely receive cephalosporins (<2% cross-reactivity with late-generation cephalosporins).

Reference: eTG – 2025 – Antibiotic Guidelines; ACSQHC – 2024 – Antimicrobial Stewardship; ASCIA – 2024 – Drug Allergy