Underutilization of Penicillin Skin Testing in the Outpatient Setting.
Saturday, March 3, 2018
South Hall A2 (Convention Center)
Omar Waqar, MD, Artemio M. Jongco, MD PhD MPH FAAAAI, Roxanne C. Oriel, MD
RATIONALE: Penicillin allergy is the most frequently reported medication allergy, however >90% of patients who report a history of penicillin allergy have negative penicillin skin testing (PST). Previous studies have demonstrated that PST plays a critical role in antibiotic stewardship, yet testing remains underutilized in the outpatient setting.

METHODS: A retrospective chart review of adults aged ≥18 in an outpatient academic Allergy and Immunology practice over a 3-year period was performed. ICD-9/10 codes related to penicillin allergy were used to identify eligible subjects from the electronic medical record (EMR). Demographics, PST and challenge results, reasons PST was not performed, and penicillin allergy documentation before/after testing were recorded. Descriptive statistics were generated.

RESULTS: Of 406 charts reviewed, 122 patients met inclusion criteria. 96.7% (N=118) of patients had their penicillin allergy evaluated. Of these, 67.8% (N=80) underwent PST and 88.8% (N=71) had negative PST. Reasons why PST was not performed included deferral to a future visit (68.4%,N=26), recent antihistamine use (10.5%,N=4), refusal of testing (7.9%,N=3), and history of previously tolerating beta-lactam antibiotics (7.9%,N=3). In patients with negative PST, 66.2% (N=47) did not undergo a penicillin challenge. Of those who underwent challenge, 83.3% (N=20) tolerated the drug, but penicillin allergy remained listed in the EMR for 45% (N=7).

CONCLUSIONS: Discussing penicillin allergy does not always lead to PST and challenge. Allergists must be vigilant about following up these discussions with actions, including updating the allergy status in the EMR after successful challenges. Future work is needed to better define allergists’ and patients’ reasons for not utilizing PST.