Playing the Long Game: Documented Penicillin Allergies Require Follow-up

More than 95% of the people in the United States with a documented penicillin allergy can actually be treated safely with that category of antibiotics, according to a new paper published in the Journal of the American Medical Association.

Physicians from Massachusetts General Hospital (MGH), Kaiser Permanente, and Northwestern Medicine at Northwestern University worked together to outline recommendations for the evaluation and management of penicillin allergies in order to ultimately decrease the use of other broad-spectrum antibiotics which can contribute to antimicrobial resistance when widely used.

“We want to encourage all providers to think about how penicillin allergies might unnecessarily interfere with their optimal treatment and contribute to antibiotic resistance,” senior author Kimberly Blumenthal, MD, MSc, who works in the Division of Rheumatology, Allergy, and Immunology at MGH, told Contagion^®. “We have accumulating evidence that a penicillin allergy is not benign, and we have methods to safely evaluate penicillin allergies. Our aim was to inform clinicians about why penicillin allergy evaluations are important and to simplify the approach to penicillin allergy evaluations.”

The problem with penicillin allergies stems from overreporting and underverification of true Immunoglobulin E (IgE)-mediated reactions, according to Dr. Blumenthal.

“More than 95% of patients who do not have a history of serious penicillin allergy reactions are penicillin tolerant because (1) the most commonly reported penicillin hypersensitivity reaction is a delayed benign rash, likely a type IV hypersensitivity reaction and these reactions may or may not recur when patients are reexposed to penicillin,” the authors write. “[Secondly,] IgE-mediated penicillin allergy wanes over time, with 80% of patients becoming tolerant after a decade; and (3) many patients were never allergic, but may have had an intolerance or another cause for the symptoms they thought represented a penicillin reaction, such as a concomitant viral infection.”

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In the paper, Blumenthal and colleagues, including Erica Shenoy, MD, PhD, associate chief of the Infection Control Unit at MGH, mapped out strategies for health care providers, including the collection of comprehensive patient histories, carrying out penicillin evaluations in clinical settings, and employing drug challenges when appropriate.

“We worked with colleagues to create a document that we hope will be both informative and practically useful to clinicians—in addition to the narrative review, the supplement includes toolkits that can be downloaded and used in a variety of clinical settings,” Dr. Shenoy told Contagion^®. “The Patient Page was additionally created to inform patients about penicillin allergy and the impact of being labeled with a penicillin allergy—we hope that document is informative to patients and prompts them to raise this question with their doctors.”

Labeled penicillin allergies not only contribute to antimicrobial resistance, but they can also lead to an increase in illnesses such as surgical site infections.

“In work previously published by our research team, we have shown that penicillin allergy-labeled patients have an increased risk of surgical site infection and this increased risk was entirely due to the choice of peri-operative antibiotic,” Dr. Shenoy, said. “Surgical site infections are both morbid and costly, and penicillin allergy evaluation should be considered pre-operatively as a strategy to reduce the risk of surgical site infections.”

Lastly, the authors urge that penicillin allergies should not be solely assessed by allergists, but rather clinicians of various specialties in tandem.

“Evaluation of penicillin allergy is not just within the purview of specialists [like] allergists such as Dr. Blumenthal, or infectious diseases physicians such as myself,” Dr. Shenoy concluded. “We want to encourage clinicians of various specialties and role groups to understand how important it is to assess patients. and provide them with the tools to do this safely.”