De-Labeling Non-β-lactam Antibiotic Allergies: Public Health Watch

In the age of resistance, prescribing antibiotics is done with at least some degree of prudence—as it should be.

However, a new study published in the January 2020 issue of the journal Pediatrics suggests some practitioners may be using an overabundance of caution when it comes to the administration of these all-important drugs, by perhaps paying too much heed to a history of allergic reactions in certain patients. Specifically, the analysis focused on non—β-lactam antibiotics (NBLAs).

“Our study shows that removing antibiotic allergies is a critical part of antibiotic stewardship,” Amanda Gwee, PhD, infectious diseases physician, clinical pharmacologist, and pediatrician at Royal Children’s Hospital and a senior lecturer in pediatrics at the University of Melbourne, told Contagion®. “With 8 in 10 children who reported allergic reactions to NBLAs not in fact having an allergy, this is an important opportunity to preserve first-line antibiotics and help prevent antibiotic resistance.”

Over-reporting of allergies to antibiotics is hardly new, of course. The most commonly reported drug allergy globally—with a prevalence rate of 5% to 10%—involves penicillin, a β-lactam.

Among children, the most commonly reported antibiotic allergy involves amoxicillin. According to a review published in May 2018, also in Pediatrics, of all adverse drug reactions reported in children in the United States, 23% are caused by non—β-lactam antibiotics.

Still, these drugs remain among the most commonly prescribed—due primarily to their (relatively) favorable resistance profile. Indeed, according to Gwee, in Australia, where she and her colleagues are based, NBLAs account for nearly half of all antibiotics prescribed in Australian pediatric hospitals.

So, knowing the degree to which allergic reactions to the drugs are, in fact, a risk is obviously paramount. And yet, in many countries, including Australia and the United States, data are lacking.

To address this, Gwee and her colleagues reviewed the cases of 141 children with suspected NBLA allergy who had skin testing and/or an intravenous or oral challenge test (OCT) between May 2011 and June 2018. The children included had 150 allergy evaluations for 15 different NBLAs.

The team found that the median time from the initial reported reaction to allergy evaluation was 1.9 years. Overall, 27 of the 150 (18.0%) challenge tests to NBLAs had positive results, with the highest rate of positive OCT results for trimethoprim-sulfamethoxazole (15 of 46 or 32.6%) and macrolides (8 of 77 or 10.4%). Although 4 children reported anaphylactic reactions, no patients had severe symptoms on re-challenge or required adrenaline.

Of the challenges that had positive results, the majority of children (23 of 27 or 85.2%) had symptoms on repeat challenge similar to those that were initially reported.

“The most important thing clinicians can do for children with drug allergies is to refer them for an allergy evaluation,” Gwee noted. “Our study showed that patients waited a median time of 1.9 years, but up to 14.9 years, to have their allergy investigated. By removing the allergy label, we can prevent the life-long, unnecessary avoidance of important antibiotic classes.”