Majority of Australians who report penicillin allergy not truly allergic

Recent changes to Australian guidelines for diagnosing penicillin allergies reveal that the majority of Australians who report such an allergy are not truly allergic, according to the peak body for immunologists. Penicillin, one of the most commonly prescribed antibiotics in Australia, was previously believed to cause allergies in 10% of Australians, which equates to approximately 2.8 million people. However, new evidence suggests that up to 90% of these individuals may not have a genuine penicillin allergy.

The Australasian Society of Clinical Immunology and Allergy has updated its guidelines, which have been published in the Journal of Allergy and Clinical Immunology. These changes provide healthcare professionals with peer-reviewed and updated advice on diagnosing and managing penicillin allergies, as well as when to refer patients to specialists. The guidelines aim to reduce hospital stays and tackle antimicrobial resistance.

Misdiagnosis often occurs due to various reasons, such as people assuming a rash or nausea after taking penicillin is an allergy, doctors being overly cautious and recording side-effects as allergies, or individuals carrying the diagnosis from childhood without questioning it. Moreover, some side-effects might be attributed to the illness itself rather than the medication.

Penicillin remains an important antibiotic option due to its effectiveness against common infections. It is a narrow spectrum antibiotic, meaning it specifically targets the bacteria causing the infection. With patients avoiding narrow classes of drugs, broader spectrum antibiotics must be used, which can negatively impact the gut microbiome and increase the risk of superbugs. Superbugs are strains of bacteria highly resistant to multiple standard treatments.

Antimicrobial resistance is a significant issue that extends beyond individual patients, as resistant bacteria can spread between people and communities. If someone develops a serious infection caused by a resistant bacteria, doctors may be left with limited treatment options.

Dr Nick Cooling, chair of the Royal Australian College of General Practitioners’ allergy special interest group, emphasizes that the guidelines are based on the latest evidence and a consensus report from various medical specialities. He hopes the guidance will reduce healthcare costs and ease the burden on immunologists, as patients with a penicillin allergy label tend to have more hospital stays and incur higher costs due to multiple treatment trials, side-effects, and delays in finding alternative treatments.

To clarify penicillin allergies among patients, Cooling encourages all health professionals to be involved in the process, as de-labeling around 2.8 million Australians cannot be achieved solely by 300 immunologists. He suggests that affected patients should discuss their penicillin allergy status with their GP, and in cases where the risk of harm is low, doctors could prescribe and monitor penicillin use.

However, Cooling warns against self-testing for penicillin allergies, as antibiotics should only be taken when prescribed for the individual patient.