Penicillin Allergy?

Is that penicillin or amoxicillin allergy real? Probably not. In this episode, we explore how to assess risk, talk to parents, and refer for delabeling. You’ll also learn what happens in the allergy clinic, why the label matters, and how to be a better antimicrobial steward.

Learning Objectives

1. Describe the mechanisms and clinical manifestations of immediate and delayed hypersensitivity reactions to penicillin, including diagnostic criteria and risk stratification tools such as the PEN-FAST score.
2. Differentiate between low-, moderate-, and high-risk penicillin allergy histories in pediatric patients and identify appropriate candidates for direct oral challenge or allergy referral based on current evidence and guidelines.
3. Formulate an evidence-based approach for evaluating and counseling families in the Emergency Department about reported penicillin allergies, including when to recommend outpatient referral for formal delabeling.

Connect with Brad Sobolewski

PEMBlog: PEMBlog.com

Blue Sky: @bradsobo

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Instagram: Brad Sobolewski

References

Khan DA, Banerji A, Blumenthal KG, et al. Drug Allergy: A 2022 Practice Parameter Update. J Allergy Clin Immunol. 2022;150(6):1333-1393. doi:10.1016/j.jaci.2022.08.028

Moral L, Toral T, Muñoz C, et al. Direct Oral Challenge for Immediate and Non-Immediate Beta-Lactam Allergy in Children. Pediatr Allergy Immunol. 2024;35(3):e14096. doi:10.1111/pai.14096

Castells M, Khan DA, Phillips EJ. Penicillin Allergy. N Engl J Med. 2019;381(24):2338-2351. doi:10.1056/NEJMra1807761

Shenoy ES, Macy E, Rowe T, Blumenthal KG. Evaluation and Management of Penicillin Allergy: A Review.JAMA. 2019;321(2):188–199. doi:10.1001/jama.2018.19283

Transcript

Note: This transcript was partially completed with the use of the Descript AI and the Chat GPT 5 AI

 Welcome to PEM Currents, the Pediatric Emergency Medicine podcast. As always, I'm your host, Brad Sobolewski, and today we are taking on a label that's misleading, persistent. Far too common penicillin allergy, it's often based on incomplete or inaccurate information, and it may end up limiting safe and effective treatment, especially for the kids that we see in the emergency department.

I think you've all seen a patient where you're like. I don't think this kid's really allergic to amoxicillin, but what do you do about it? In this episode, we're gonna break down the evidence, walk through what actually happens during de labeling and dedicated allergy clinics. Highlight some validated tools like the pen FAST score, which I'd never heard of before.

Preparing for this episode and discuss the current and future role of ED based penicillin allergy testing. Okay, so about 10% of patients carry a penicillin allergy label, but more than 90% are not truly allergic. And this label can be really problematic in kids. It limits first line treatment choices like amoxicillin, otitis media, or penicillin for strep throat, and instead.

Kids get prescribed second line agents that are less effective, broader spectrum, maybe more toxic or poorly tolerated and associated with a higher risk of antimicrobial resistance. So it's not just an EMR checkbox, it's a label with some real clinical consequences. And it's one, we have a role in removing.

And so let's understand what allergy really means. And most patients with a reported penicillin allergy, especially kids, aren't true allergies in the immunologic sense. Common misinterpretations include a delayed rash, a maculopapular, or viral exum, or benign, delayed hypersensitivity, side effects, nausea, vomiting, and diarrhea.

And unverified childhood reactions that are undocumented and nonspecific. Most of these are not true allergies. Only a very sm