Q&A: Patients with verified penicillin allergies safely receive cephalosporins

Key takeaways:

• The safety of cephalosporins for patients with verified penicillin allergies has not been well-studied.
• Cephalosporins appeared safe, even in patients with penicillin allergies verified by testing.

High-risk patients who had a verified penicillin allergy safely received cephalosporins, according to a letter published in The Journal of Allergy and Clinical Immunology: In Practice.

Fifty patients received 77 unique cephalosporin courses or drug challenges. One patient reacted to an aminocephalosporin. None of the other patients had any reactions.

Healio spoke with lead author Ami P. Belmont, MD, instructor in the section of rheumatology, allergy and immunology at Yale School of Medicine, to find out more.

Healio: What prompted this study?

Belmont: It is now well-known that most patients with reported penicillin allergies, or rather penicillin allergy labels, are not actually allergic to penicillin. These inaccurate allergy labels are associated with a myriad of worse health outcomes.

The most recent drug allergy practice parameter update from the Joint Task Force of the American Academy of Allergy, Asthma & Immunology and the American College of Allergy, Asthma & Immunology, which was released in 2022, highlights that patients with non-anaphylactic unverified penicillin allergies can receive cephalosporins without testing, and patients with a history of anaphylaxis to penicillin can be given cephalosporins with structurally dissimilar R1 side chains without testing.

However, less has been published about patients with verified penicillin allergy — in other words, those patients who have had prior positive testing for penicillin allergy with an allergist.

Prior research assessing the risk of cephalosporin administration in verified penicillin allergy was primarily from Europe, where aminopenicillin allergy is more prevalent than in the United States. Our study aimed to address a gap in the literature assessing the risk of giving cephalosporins to patients with verified penicillin allergies in the U.S.

Healio: Were there any particularly surprising or significant findings that you would like to highlight?

Belmont: Our study showed that 50 patients with verified penicillin allergies largely tolerated cephalosporins. This included 52 administrations of cephalosporins with dissimilar side chains (68%) and 25 administrations of cephalosporins with similar side chains (32%). In 77 courses of cephalosporins, there was only one reaction, which was nonsevere (cutaneous only) and may be explained by other factors. These results suggest that cephalosporins are largely safe, even in patients who have penicillin allergies that are verified by allergist testing.

Healio: How can doctors use these findings to improve care?

Belmont: Patients with penicillin allergy labels are at higher risk for adverse health outcomes, many of which are mediated by utilization of alternative antibiotics, which are often less effective, more broad-spectrum, have higher side effect profiles and are more costly. Expanding the use of cephalosporins in this patient population would likely reduce some of these risks and is of great importance to public health.

We believe these findings should promote behavioral change in cephalosporin prescribing patterns and can work in concert with the aforementioned guidance in the recently updated drug allergy practice parameters.

Healio: What is the next step in this research?

Belmont: Limitations of this study include its retrospective nature and relatively small size (50 patients). Future studies are needed to evaluate whether these findings can extend to patients with verified penicillin allergy who experienced recent or severe reactions.

Reference:

• Belmont AP, et al. J Allergy Clin Immunol Pract. 2023;doi:10.1016/j.jaip.2023.05.027.

For more information:

Ami P. Belmont, MD, can be reached at ami.belmont@yale.edu.