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World-first study into penicillin allergy at Austin Health

Austin Health's Infectious Diseases Physician Dr Morgan Rose standing in front of sign for Intensive Care Unit

4 June 2024

Dr Morgan Rose, a PhD student and infectious diseases physician at Austin Health, recently published a world-first study into penicillin allergy in top critical care journal, Intensive Care Medicine.  

Dr Rose completed the world’s first randomised control trial of a tablet test dose for low-risk penicillin in intensive care units (ICUs). The study included 80 critically ill patients in four Melbourne ICUs who said they were allergic to penicillin. Each patient consented to being randomly assigned to receive either a tablet test dose of penicillin or routine care without a test dose.   

Dr Rose found that 98 per cent of patients had no allergic reaction, even after repeat doses of penicillin. There were no serious adverse reactions – patients with a reaction only experienced a mild rash.  

Penicillins are excellent antibiotics because they can treat a wide range of infections while being well tolerated and highly effective. While they are often the antibiotics of choice for a hospital’s sickest patients, almost 7 per cent of ICU patients believe they have a penicillin allergy, so don’t receive it.

Allergic or not? 

There are several possible reasons for confusion around penicillin allergies. Penicillin allergies can fade over a person’s lifetime. They can be mistakenly diagnosed – for example a viral rash could be interpreted as an allergic reaction. 

Dr Rose's work will be of great benefit to some of the hospital’s sickest patients.

“Patients in intensive care have a greater need for antibiotics. By demonstrating that ICU patients no longer have a penicillin allergy, we can offer them the best possible care when they need it most.”  

This groundbreaking research could help shift public perception. Dr Rose was particularly excited to see that most of the patients in the study went on to take additional doses of penicillin after the trial dose, removing the label of ‘penicillin allergic’. He plans to replicate the study again, with a higher number of patients, and continue to communicate his findings about penicillin allergy in adults.  

What patients need to know

Dr Rose explains that if you have a penicillin allergy, or think you’ve had a reaction to penicillin in the past, discuss this with your GP, from where you can be referred to our Antibiotic Allergy Clinic. It’s always best to be tested when you are well, rather than when you’re being treated in hospital for an illness. 

This new research builds on existing work from Austin Health. In 2022, Infectious Diseases Physician Prof Jason Trubiano launched the National Antibiotic Allergy Network (NAAN), which connected more than 40 hospitals from Australia and New Zealand to determine who is truly allergic and who can safely use penicillin after a test dose procedure. The resulting app and network saves lives and improves health care by helping patients get the most effective antibiotic, and collects data for further research.