Documenting Penicillin Allergy: The Impact of Inconsistency

PLoS One. 2016 Mar 16;11(3):e0150514. doi: 10.1371/journal.pone.0150514. eCollection 2016.


Background: Allergy documentation is frequently inconsistent and incomplete. The impact of this variability on subsequent treatment is not well described.

Objective: To determine how allergy documentation affects subsequent antibiotic choice.

Design: Retrospective, cohort study.

Participants: 232,616 adult patients seen by 199 primary care providers (PCPs) between January 1, 2009 and January 1, 2014 at an academic medical system.

Main measures: Inter-physician variation in beta-lactam allergy documentation; antibiotic treatment following beta-lactam allergy documentation.

Key results: 15.6% of patients had a reported beta-lactam allergy. Of those patients, 39.8% had a specific allergen identified and 22.7% had allergic reaction characteristics documented. Variation between PCPs was greater than would be expected by chance (all p<0.001) in the percentage of their patients with a documented beta-lactam allergy (7.9% to 24.8%), identification of a specific allergen (e.g. amoxicillin as opposed to "penicillins") (24.0% to 58.2%) and documentation of the reaction characteristics (5.4% to 51.9%). After beta-lactam allergy documentation, patients were less likely to receive penicillins (Relative Risk [RR] 0.16 [95% Confidence Interval: 0.15-0.17]) and cephalosporins (RR 0.28 [95% CI 0.27-0.30]) and more likely to receive fluoroquinolones (RR 1.5 [95% CI 1.5-1.6]), clindamycin (RR 3.8 [95% CI 3.6-4.0]) and vancomycin (RR 5.0 [95% CI 4.3-5.8]). Among patients with beta-lactam allergy, rechallenge was more likely when a specific allergen was identified (RR 1.6 [95% CI 1.5-1.8]) and when reaction characteristics were documented (RR 2.0 [95% CI 1.8-2.2]).

Conclusions: Provider documentation of beta-lactam allergy is highly variable, and details of the allergy are infrequently documented. Classification of a patient as beta-lactam allergic and incomplete documentation regarding the details of the allergy lead to beta-lactam avoidance and use of other antimicrobial agents, behaviors that may adversely impact care quality and cost.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Drug Hypersensitivity / diagnosis*
  • Female
  • Humans
  • Male
  • Middle Aged
  • Penicillins / adverse effects*
  • Retrospective Studies
  • Sensitivity and Specificity


  • Penicillins

Grants and funding

AR received funding through NorthShore University HealthSystems, ( The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.