Victor De Schwanberg / Science Photo Library
Almost 90% of people whose medical records labelled them as allergic to penicillin were not truly allergic, a study funded by the National Institute for Health and Care Research has suggested.
Results of the ‘ALABAMA’ study, published in The Lancet Primary Care on 14 July 2025, found that 88% of people with a penicillin allergy or sensitivity had their label removed from their medical records.
The study analysed data from 811 people recruited from UK general practices.
Half of the participants (49%) underwent the penicillin allergy assessment pathway and were given a penicillin oral challenge, skin challenge or both.
People with a penicillin allergy label, and who need an antibiotic, are offered non-penicillin antibiotics, which can lead to decreased penicillin use and increased non-penicillin antibiotic prescribing.
A penicillin allergy checklist, published by the Royal Pharmaceutical Society (RPS) in 2023, states that fewer than 10% of patients with a penicillin allergy label are likely to have a true allergy to penicillin.
“Up to 4 million people across the UK may have an incorrect allergy status record, putting them at increased risk of harm,” it added.
The checklist also notes that when a patient is labelled as allergic to penicillin, they are offered broader-spectrum antibiotics which “increases the risk of multi-drug resistance”.
World Health Organization (WHO) guidance on antimicrobial stewardship interventions, published in 2023, highlights that antibiotic allergy labelling “often leads to overly broad antimicrobial coverage” and can lead to “longer duration antibiotic therapy”.
The WHO added that de-labelling “can be an effective strategy to promote antimicrobial stewardship”.
Sue Pavitt, professor in translational and applied health research at the University of Leeds and lead author of the study, said that her mother, Rosie Woollard, died of an antimicrobial resistant infection aged 91 years, having had the penicillin allergy label on her medical records for many years.
“When my mum got older and had more underlying health problems, we noticed that when she had an infection, she often needed two or three courses of different antibiotics before the infection would clear,” Pavitt said.
“Each round of antibiotics took a toll on her wellbeing, appetite and ability to bounce back until the infection was under control.”
Commenting on the study, Mark Gilchrist, a member of the RPS Antimicrobial Expert Advisory Group, said: “Many people are wrongly labelled as allergic to penicillin, which can lead to less effective treatment, longer recovery times and increased risk of hospital admission. This study highlights the value of penicillin allergy assessments in improving patient care and tackling antimicrobial resistance.
“Pharmacists are well placed to support conversations about penicillin allergy, using tools like the RPS checklist to help identify those who may benefit from further assessment.
“With the right support and collaboration, pharmacists can play a greater role in delivering and supporting delabelling services,” he added.
A UK study published in the Journal of Infection in February 2024 found that 97% of patients who were labelled as allergic to penicillin were, after assessment, found to have no allergy.
In addition, a study published in March 2024 found that pharmacists could safely assess mislabelled penicillin allergy.
