Predicting True Penicillin Allergy in Adults
Am Fam Physician. 2021 Jun 15;103(12):760-761.
Author disclosure: No relevant financial affiliations.
In patients reporting a penicillin allergy, is it possible to determine the likelihood of true allergy without formal testing?
Penicillin allergy is the most commonly documented drug allergy in medical records, with a prevalence of approximately 10% of all patients.1 However, in up to 90% of patients with a reported allergy, penicillins are tolerated on allergy testing.2 As a consequence of patients being labeled as having a penicillin allergy, alternative (typically broader-spectrum) antibiotic classes are often used, with potentially poorer efficacy and safety profiles. This leads to increased multidrug-resistant organisms, treatment failure, and health care costs and prolonged hospitalizations.3
A formal drug challenge is the preferred test for investigating immunoglobulin E–mediated penicillin hypersensitivity (type I hypersensitivity)4; skin testing is also a commonly used validated tool.1 A number of studies have been performed to develop clinical prediction rules using features of the allergy history to help determine which patients labeled as having a penicillin allergy can safely be given a beta-lactam antibiotic. Despite the high prevalence of patients labeled as having a penicillin allergy, there is an international shortage of those proficient in conducting formal drug challenges.5
A study in a tertiary referral center in the United Kingdom used multivariable logistic regression to identify patients at low risk of type I beta-lactam allergy.6 This included patients who had no history of anaphylaxis, who had a reaction more than one year before referral, and who could not recall what the index drug was. Only 1.6% of patients with all of these traits had type I hypersensitivity. Another study derived and validated two algorithms in a retrospective cohort of individuals evaluated for beta-lactam allergy.7 Similarly, anaphylaxis, shorter time since the reaction occurred, and reaction onset less than one hour after most recent
Referencesshow all references
1. Sacco KA, Bates A, Brigham TJ, et al. Clinical outcomes following inpatient penicillin allergy testing: a systematic review and meta-analysis. Allergy. 2017;72(9):1288–1296....
2. Joint Task Force on Practice Parameters; American Academy of Allergy, Asthma and Immunology; American College of Allergy, Asthma and Immunology; Joint Council of Allergy Asthma and Immunology. Drug allergy: an updated practice parameter. Ann Allergy Asthma Immunol. 2010;105(4):259–273.
3. Shenoy ES, Macy E, Rowe T, et al. Evaluation and management of penicillin allergy: a review. JAMA. 2019;321(2):188–199.
4. Gruchalla RS, Pirmohamed M. Clinical practice. Antibiotic allergy. N Engl J Med. 2006;354(6):601–609.
5. Trubiano JA, Beekmann SE, Worth LJ, et al. Improving antimicrobial stewardship by antibiotic allergy delabeling: evaluation of knowledge, attitude, and practices throughout the emerging infections network. Open Forum Infect Dis. 2016;3(3):ofw153.
6. Siew LQC, Li PH, Watts TJ, et al. Identifying low-risk beta-lactam allergy patients in a UK tertiary centre. J Allergy Clin Immunol Pract. 2019;7(7):2173–2181.e1.
7. Chiriac AM, Wang Y, Schrijvers R, et al. Designing predictive models for beta-lactam allergy using the drug allergy and hypersensitivity database. J Allergy Clin Immunol Pract. 2018;6(1):139–148.e2.
8. Trubiano JA, Vogrin S, Chua KYL, et al. Development and validation of a penicillin allergy clinical decision rule. JAMA Intern Med. 2020;180(5):745–752.
9. Salkind AR, Cuddy PG, Foxworth JW. The rational clinical examination. Is this patient allergic to penicillin? An evidence-based analysis of the likelihood of penicillin allergy. JAMA. 2001;285(19):2498–2505.
10. Macy E, Ho NJ. Adverse reactions associated with therapeutic antibiotic use after penicillin skin testing. Perm J. 2011;15(2):31–37.
This guide is one in a series that offers evidence-based tools to assist family physicians in improving their decision-making at the point of care.
This series is coordinated by Mark H. Ebell, MD, MS, deputy editor for evidence-based medicine.
A collection of Point-of-Care Guides published in AFP is available at https://www.aafp.org/afp/poc.
Copyright © 2021 by the American Academy of Family Physicians.
This content is owned by the AAFP. A person viewing it online may make one printout of the material and may use that printout only for his or her personal, non-commercial reference. This material may not otherwise be downloaded, copied, printed, stored, transmitted or reproduced in any medium, whether now known or later invented, except as authorized in writing by the AAFP. Contact email@example.com for copyright questions and/or permission requests.
Want to use this article elsewhere? Get Permissions