The following was originally posted by PW blogger Jasmine Marcelin, MD, to the University of Nebraska Medical Center Division of Infectious Diseases blog.


The following was previously posted by Dr. Marcelin to SHEA Journal Club published online in January 2019.

Although 10% of Americans report penicillin allergies, 90% of those allergies are not substantiated. Up to 25% of patients living with cancer report penicillin allergies, but more than half of these are low risk and could tolerate beta-lactams. Cancer patients are likely to receive inappropriate antibiotics for a documented penicillin allergy because they are immunocompromised, therefore “special”. Additionally, admission for systemic illness like neutropenic fever, it may not be convenient to schedule penicillin skin testing, and other medications could interfere with skin testing.

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Trubiano et al. focused specifically on cancer patients to test the feasibility of implementing an oral penicillin challenge program as a means to de-label inappropriate penicillin allergies in cancer patients. Of 98 patients with low-risk penicillin allergy, only 46 met the inclusion criteria and consented to participate, 23 of whom had either solid-organ or hematological cancer.

The study included inpatient and outpatients. An ID physician performed a detailed history and cleared patients for oral penicillin challenge, in the form of a dose of either penicillin VK or amoxicillin, administered by an antimicrobial stewardship nurse.

All 46 patients tolerated the challenge and were successfully de-labelled. Beta lactams were more likely to be prescribed post challenge than pre challenge. (22/26, 84.6% vs 1/31, 3.2%; P < .001), a difference that remained after stratification for different variations of specific beta-lactams.

Despite the small size of the pilot study, this work is important because most penicillin challenge studies have focused on children and immunocompetent patients. Given the significant use of antibiotics in the cancer population, results like this can inform larger studies, or provide impetus to consider implementation of similar de-labelling programs when skin testing is not available.