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Using Penicillin Allergy Assessments to Decrease HAI Rates

Up to 17% of patients report having a penicillin allergy; however literature states that 80%-90% are not actually allergic reactions. 2,3, 4-5  Patients are not trained to differentiate an allergy from and adverse drug event and thus do not have the clinical vocabulary to describe their reaction other than to name it an allergy, leading to a discrepancy in data. Busy or undereducated staff usually take the patient at their word without investigating further, resulting in incomplete reaction histories. Prescribers then apply this inaccurate information to the medication selection process. Further compounding the problem, pharmacists often mistakenly believe that a patient with a penicillin allergy is not an acceptable candidate for cephalosporin therapy due to the risk of cross-reactivity. All of these issues lead to the unnecessary avoidance of beta-lactams in these patients.  It is high time we move towards a culture shift.

A retrospective, matched cohort study of 51,582 patients reported that patients with a penicillin allergy have poorer outcomes than patients without a penicillin allergy.  Average hospital stays for penicillin allergic patients were 0.59 days longer and they experienced significantly higher utilization of fluoroquinolones, clindamycin, and vancomycin. Additionally, the patients with reported penicillin allergies had a 23.4% increase in incidence of C. difficle infections, a 14.1% increase in MRSA infections, and a 30.1% increase in VRE infections as compared to the matched cohort. 4

Antimicrobial stewardship leadership should enforce the practice of reviewing the clinical history of patients with a reported beta?lactam allergy, focusing not only on identifying non?immunologic versus immunologic reactions, which can be determined by examining the nature of symptoms and the timing of the event;6 but also by reviewing the patient’s previous medication use information. Proof of subsequent beta-lactam administration without a reaction may already be available in the patient’s medical record, but if the historian is not prompted to seek this information, it may as well be lost. This is a prime example of being data rich but information poor.

For those clinicians who do not relish the idea of challenging a patient with penicillin administration in order to test their reaction, a commercially available penicillin allergy test is available that if used with penicillin G can reportedly identify 97% of patients with an IgE mediated penicillin allergy. Results can be obtained in about one hour and costs around $80.7,8

Implementing penicillin allergy assessments can help decrease length of stay and decrease healthcare-associated infection rates. A high-performing antimicrobial stewardship program should have physician leaders that stress the importance of reviewing patients’ clinical history and medication administration for this appropriate information. 



  1. Frumin J, Gallagher JC. Allergic cross-sensitivity between penicillin, carbapenem, and monobactam antibiotics: what are the chances? Ann Pharmacother 2009;43:304-315.

  2. Prescott WA, DePestel DD, Ellis JJ, et al. Incidence of carbapenem-associated allergic-type reactions among patients with versus patients without a reported penicillin allergy. Clin Infect Dis 2004;38:1102-1107.

  3. Salkind AR, Cuddy PG, Foxworth JW. Is this patient allergic to penicillin? An evidence-based analysis of the likelihood of penicillin allergy. JAMA 2001;285:2498-2505.

  4. Macy E, Contreras R. Health care use and serious infection prevalence associated with penicillin “allergy” in hospitalized patients: A cohort study. J Allergy Clin Immunol 2014;133:790-796.

  5. Terico AT, Gallagher JC. Beta-lactam hypersensitivity and cross-reactivity. J Pharm Practice 2014; [epub ahead of print]

  6. Lieberman P, Kemp SF, Oppenheimer J, et al. The diagnosis and management of anaphylaxis: an updated practice parameter. J Allergy Clin Immunol 2005;115:S483-S523.

  7. Pre-Pen®. Website Accessed April 14, 2015.

  8. Lexicomp Online. Lexi-Drugs Online, Hudson, Ohio: Lexi-Comp, Inc.; Accessed April 14, 2015.

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