Implementation and Impact of a β-Lactam Allergy Assessment Protocol in a Veteran Population

Abstract

Background: Approximately 10% of the US population reports having a β-lactam allergy, although nearly 90% do not have a true immunoglobulin E (IgE)-mediated reaction. This misconception results in using nonpreferred antibiotics, leading to antimicrobial resistance and treatment failure. To evaluate, clarify, and clear β-lactam allergies, we implemented a pharmacist-driven β-lactam allergy assessment (BLAA) protocol and penicillin allergy clinic (PAC). The purpose of this study was to illustrate the BLAA process, including the pharmacist-run PAC, and assess the impact on allergy clearance.

Methods: Clinical pharmacy specialists (CPS) evaluated hospitalized veterans with β-lactam allergies, using the BLAA protocol. Eligible patients could later be seen in PAC. This was a retrospective observational review of the BLAA protocol to assess recommendations for β-lactam antibiotic use and PAC outcomes.

Results: Between November 2017 and February 2020, 278 patients were evaluated, and 32 were seen in the clinic. The most common allergen was penicillin, and the most reported reaction was a rash (27%) or pruritus and urticaria (18%). Through PAC and the BLAA protocol, 86 patients (31%) were cleared for allergy removal, and 188 (68%) were cleared for alternative β-lactams. The evaluation revealed that 274 patients (99%) were eligible to receive a β-lactam antibiotic, and only 4 patients (1%) were recommended for avoidance of all β-lactams.

Conclusions: These findings highlight the utility of the pharmacist-driven BLAA protocol. We illustrated that most patients with documented β-lactam allergies were eligible for alternative β-lactams. The implementation of the BLAA protocol and pharmacist-run PAC facilitated allergy clearance and has the potential to promote alternative β-lactam use.

FIGURE

β-Lactam Allergy Evaluations and Outcomes Abbreviations: BLAA, β-lactam allergy assessment; PAC, penicillin allergy clinic