Background: Up to 10% of hospitalized patients report an allergy to penicillin, however studies have shown that the majority of these are not clinically significant reactions.1,2 Unverified penicillin allergies increase overall patient mortality as they lead to use of broad-spectrum antibiotics that are less effective and have more side effects.3 Recent studies have found that skin testing is unnecessary to assess reported allergies in most patients, and de-labeling penicillin allergies directly through allergy assessment or utilization of the amoxicillin challenge is safe and effective.4,5

Purpose: Our multidisciplinary team created a one-page allergy questionnaire to aid internists in conducting a complete allergy assessment as well as an algorithmic flow chart to guide appropriate administration of the oral amoxicillin challenge, in order to implement an alternative allergy de-labeling strategy than traditional skin testing.

Description: Our aim statement was: 25 patients requiring one dose of antibiotics during admission to internal medicine residency services at our institution with penicillin allergies will have their allergy de-labeled through either the oral amoxicillin challenge or direct de-labeling through allergy assessment alone. One page guides for thorough allergy assessment and the process of the amoxicillin challenge were developed by an interprofessional team including a pharmacist, infectious disease specialist and internal medicine resident and distributed throughout our institution. Educational sessions were held with internists, including internal medicine residents, and floor pharmacists to establish local confidence in and knowledge of allergy assessment and amoxicillin challenge as safe allergy de-labeling methods. Monthly chart reviews were conducted to assess for successful de-labeling events. During our study period 27 de-labeling events occurred, or 63% of eligible patients. 16 patients underwent oral challenge and 11 patients were de-labeled through allergy assessment alone. Two patients reported a mild, delayed onset rash after oral challenge, treated with only an oral anti-histamine, and were thus unable to switch to a penicillin antibiotic, however all other de-labeled patients had their treatment narrowed to a penicillin antibiotic.

Conclusions: Our study demonstrated successful implementation of an algorithmic method of de-labeling penicillin allergies via the amoxicillin challenge and thorough allergy assessment in our institution. Our results also illustrate the role that de-labeling penicillin allergies has in antibiotic stewardship as all but two patients had their antibiotic narrowed to a penicillin upon completion of the challenge or successful direct de-labeling.