Background Patients are commonly reported as being allergic to beta-lactam (BL) antibiotics. However, many patients with this reported allergy are able to receive BL treatments because they do not have true allergies. In many cases these are simply intolerances due to side effects reported as an allergy. Delabelling these patients leads to better clinical outcomes, optimal antibiotic usage, decreased bacterial resistance and reduced healthcare costs. Therefore, the aims of this study were to identify incorrectly labelled BL allergies in hospitalised patients and to assess antibiotic use in delabelled patients in order to establish a quality indicator to optimise antimicrobial treatments.

Methods A prospective study was conducted in which hospitalised patients treated with antimicrobial drugs and labelled as ‘BL-allergic’ were identified by clinical pharmacists. An allergist assessed whether patients were suitable candidates for a skin test or oral challenge. The Allergy Service removed ‘BL-allergic’ labels if negative results were obtained. Delabelled patients were followed up by clinical pharmacists to study the use of BL antibiotics as a result of the delabelling programme.

Results A total of 176 suspected allergic patients were identified and 91 (51.7%) were tested either by a skin test or oral challenge based on the patient indicators. Seven (16.4%) patients tested were allergic to BL antibiotics, 76 (83.5%) were totally delabelled and eight (0.1%) were partially delabelled. Thirty-two (38.1%) delabelled patients required antibiotic treatment in another inpatient or outpatient setting, of whom 27 (84.3%) patients with a new infectious episode received BL treatments while five (15.7%) continued to receive antimicrobial treatments without BL.

Conclusion After the implementation of a protocol to detect incorrect BL allergy labels, 83.5% of the patients in this cohort were completely delabelled. This shows that there is a clear opportunity to optimise the use of antibiotics by delabelling ‘BL-allergic’ patients.