Antibiotics
Elizabeth Briand
"Penicillin is the most prevalent reported drug allergy,” said Tracy Zembles, PharmD. In fact, about 10% of the population reports a penicillin allergy. “However, about 95% of those are not truly allergic when formally evaluated,” said Zembles, who is co-director for the antimicrobial stewardship program at Children’s Wisconsin in Milwaukee.
A new study published by a team of Greek researchers in the October 2, 2025, issue of Acta Paediatrica examined overdiagnosis of antibiotic allergies. The findings demonstrate that delabeling, or correcting a diagnosis of antibiotic allergies, can positively influence a child’s future care and health, safely opening the door to a broader and more appropriate range of effective treatments.
Benefits of delabeling
The study followed the cases of 123 children who, between 2017 and 2020, had a suspected antibiotic allergy. After thorough testing, 17 children were confirmed to be allergic and were removed from the study. The remaining 106 children were formally delabeled for the allergy.
After 5 years, researchers followed up with the children’s families to find out if they had reused the previously suspected antibiotic and, if so, whether any adverse reactions had occurred.
Results showed that a significant majority of children—more than 76%—had reused the antibiotic at least once over the 5-year period, most often for otitis media and respiratory tract infections. The most frequently reused antibiotics were penicillins at 57%, followed by macrolides (24%), and cephalosporins (19%).
The study authors went on to note that adverse events following reuse were uncommon—in fact, only three children reported mild cutaneous reactions. None of the reactions required medication or discontinuation of the antibiotic, and all went away on their own. Notably, the responses among these three patients were all milder than the ones that had led to the original allergy diagnosis.
A not-so-rare occurrence
Too often, perceived allergies may prevent a clinician from prescribing what might be the most effective antibiotic to treat an infection, limiting the options available for a sick child. For children labeled as having a penicillin allergy, for example, they may be given alternative antibiotic regimens that may be less effective, more toxic, and/or more expensive than preferred, first-line agents, according to Zembles.
“The use of alternative agents in patients with reported penicillin allergies have been associated with increased risk of developing
Clostridioides difficile infection, increased risk of acquiring subsequent multi-drug-resistant organisms, longer hospital stays, and even mortality,” said Zembles.
Overdiagnosis is also a contributor to the global problem of antimicrobial resistance.
For children suspected of an antibiotic allergy, thorough testing by a clinical expert can avoid an incorrect label and all of the challenges that come with it.
“There are two main ways [to test]: skin testing or oral drug challenge, and which one is selected is based on the severity of the initial allergy,” Zembles said.
Accurately assessing allergy risks not only benefits individual children but also global efforts to safeguard antibiotic effectiveness.
“Delabeling allergies is a priority for antimicrobial stewardship programs, whose main goal is to optimize antimicrobial therapy while limiting unintended consequences,” said Zembles.
Some health care institutions have their own pharmacist-led delabeling programs, while others may refer patients to allergy clinics. ■