New Guidance on Implementing Penicillin Allergy Skin Testing Compiled by US Pharmacists

Estimates indicate that 10% of US patients report having an allergic reaction to a penicillin antibiotic at some point in their lives, yet only 1% of the population are truly allergic to this class of antibiotics.

Documentation of a penicillin allergy can lead to patients receiving broad-spectrum therapy that can result in increased costs, the use of more health care resources, and decreased overall clinical outcomes. Because of this, antimicrobial stewardship programs have prioritized addressing inappropriate prescribing in patients with a documented allergy.

The Infectious Diseases Society of America (IDSA) has included using penicillin allergy skin testing (PAST) in some patients to improve prescribing in new antimicrobial stewardship guidelines. Studies have demonstrated the utility of PAST as a tool to reduce the risk of exposure, optimize the selection of antimicrobials, and improve patient outcomes.

Although PAST has been implemented in various health care facilities and institutions, questions still remain about how to appropriately implement it. As such, a team of infectious disease pharmacist colleagues from various institutions have authored a manuscript to provide a guide for other pharmacists looking to implement PAST. The guidance was published in American Journal of Health-System Pharmacists.

“What we quickly realized is that many pharmacists wanted to start this process but faced a number of logistical obstacles along the way and were having difficulty navigating how to get to the final goal of the first skin test,” Christopher M. Bland, PharmD, FCCP, FIDSA, BCPS, clinical associate professor at the University of Georgia College of Pharmacy and clinical pharmacy specialist in the St. Joseph’s/Candler Health System and first author of the manuscript, told Contagion® in an interview. “We recruited pharmacists across the country who had significant interest and experience in penicillin allergy assessment and skin testing to help us write a comprehensive ‘how to’ paper.”

The guidance seeks to address important factors to consider prior to initiating a PAST program, which include considering the benefits that patients who are mislabeled as penicillin-allergic would receive through reducing the use of broad-spectrum antibiotics, as well as how limiting exposure can also reduce the growth of resistance on a societal level.

The authors note that any patient listed with an allergy to penicillin should undergo an in-depth interview to determine the patient’s history with penicillin reactions. PAST is indicated for those patients with suspected or documented hypersensitivity, but patients with “unknown” reactions may also require PAST to rule out sensitivity.

However, skin testing may not be required for all patients, the authors indicate in the paper.

“It is important to stress that a number of patients’ self-reported penicillin allergy can be evaluated and reconciled even if skin testing procedures are not available,” Dr. Bland emphasizes. “A number of these allergies are found to be false with good medication and allergy history questioning and can safely be given a penicillin and do not require skin testing.”

For patients who do undergo testing and the results of the PAST are negative, the process of de-labeling must occur to prevent future labeling as allergic. The authors indicate that this process should be determined on each institution’s individual basis but note that one option could include entering a “place holder” in the electronic health record that provides details of the negative PAST, a tactic suggested by Bruce M. Jones, PharmD, BCPS, of St. Joseph’s/Candler Health System.

“To date, this has successfully curbed any re-labeling of penicillin allergies for patients who have re-encountered our health system,” Julie Ann Justo, PharmD, MS, BCPS-AQ ID, associate professor in the Department of Clinical Pharmacy and Outcomes Sciences at the University of South Carolina College of Pharmacy, an author on the paper, told Contagion®

Dr. Justo, who is also a member of Contagion®’s Editorial Advisory Board, also explains the importance of highlighting the role that pharmacists can play in PAST, saying: “We also felt it was important to highlight the unique role pharmacists can play in PAST. This is based on pharmacists' extensive training in verifying the appropriateness of prescriptions, investigating patient allergy histories, leading antimicrobial stewardship efforts, and more.”

According to Dr. Bland, many obstacles still exist for implementing PAST, including lack of time and resources, referencing that most pharmacists interested in PAST also have a number of other stewardship activities “competing” for their time. Additionally, Dr. Bland explains that pharmacy state boards vary on whether pharmacists within an individual state are allowed to perform skin testing within their scope of practice.

All in all, the authors of the paper are hopeful that by using this guidance, more institutions will be able to successfully implement the process of PAST.

“The most important driver of success is to treat skin testing not as a medication, but as a process,” Dr. Bland said. “Like any good process, thoughtful and detailed planning are required in order to maximize success.”

“We hope clinical pearls like these will help decrease the burden of implementation and increase the availability of PAST services for all patients,” Dr. Justo concludes.