Lower prevalence of antibiotic allergy labels in Europe

Published online: June 1, 2021

Antibiotic allergy labels (AAL) appear frequently in patients’ charts and subsequently affect future health care decisions, morbidity, and even mortality. Large studies from US centers indicate a prevalence of 10 to 15%. However, large-scale analyses of AAL in European centers are scarce, encompassing mostly smaller populations or focusing only on penicillin.

In their paper published in The Journal of Allergy and Clinical Immunology: In Practice, Gilissen et al. studied the prevalence of recorded AAL as well as characteristics of the reported reactions and registration methods in the largest tertiary referral and teaching hospital of Belgium, the University Hospitals of Leuven, evaluating records of 1,009,598 unique patients over a 9-year period. They observed an overall AAL prevalence of 3% of patients who visited the hospital, including 1% of outpatients and 7% of those hospitalized. When focusing on penicillin, prevalence was 2%; that is 1% of outpatients and 6% of inpatients. Of patients with an AAL, 9% had multiple labels and 5% had labels for multiple antibiotic classes. Most frequently, beta-lactams were involved (84% of AAL), followed by quinolones (7%) and sulfonamides and macrolides (both 3%). Moreover, 88% of the reactions were self-reported, mostly being an unspecified rash (53%), whereas only 3% were considered confirmed AAL.

This work indicates that AAL prevalence is variable and, at least in Belgium, lower when compared to reports from outside of Europe. However, this prevalence most likely still represents an overestimation of genuine antibiotic allergic patients, since most labels lack confirmation and/or specifics such as details on the specific culprit, the exact morphology and timing of the reaction, to guide differentiation between immediate and non-immediate or delayed-type reactions. Improved documentation of AAL can help minimize the burden of incorrect AAL.

Moreover, previous delabeling studies indicate that a large fraction of AAL, especially for penicillins, can be invalidated. However, re-exposure to the culprit could elicit hypersensitivity reactions in a minority of cases. Therefore, the balance between indirect harm due to an unjust AAL and potential harm due to iatrogenic re-exposure in case of a legitimate AAL needs to be carefully considered when implementing these delabeling protocols. Here, an in-depth knowledge on the local epidemiology of AAL is mandatory to estimate the impact of better allergy labeling and delabeling protocols.

The Journal of Allergy and Clinical Immunology: In Practice is an official journal of the AAAAI, focusing on practical information for the practicing clinician.

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