There are a lot of things in the world that you can be allergic to, from certain medications and foods to environmental allergens like pollen and pet dander. In some cases, you’ll accurately guess that you have an allergy because you had a reaction after encountering a specific substance, like breaking out in hives after petting a dog or swelling up after eating peanuts. In other cases, however, symptoms that seem like an allergic reaction may be caused by something else, leading you to mistakenly believe you have an allergy when you don’t.
Penicillin allergies disproportionately fall into that second category.
What is Penicillin?
Penicillin is a class of drugs used to treat bacterial infections. A few types of penicillin include:
- Penicillin G
- Penicillin V
- Amoxicillin
- Ampicillin
Doctors will prescribe either oral (syrups, pills, etc.) or intravenous (IV) penicillin depending on the situation.
How Common Are Penicillin Allergy Misdiagnoses?
Approximately 10% of U.S. patients report having a penicillin allergy. When clinicians tested those patients, less than 1% of them were truly allergic (Centers for Disease Control, 2025)[1].
Most penicillin allergy misdiagnoses happen in childhood, usually after a child’s infection causes symptoms that their doctor misattributes to the drug used to treat the infection, rather than the infection itself.
In other situations, you used to have a true penicillin allergy, but have lost it over time. Researchers found that between 80% and 100% of patients with a true penicillin allergy will test negative for the allergy ten years after the initial test[2]—meaning that patients lose about 10% sensitivity each year.
Why Should I Double-Check My Penicillin Allergy?
Penicillin is an effective class of medications for treating bacterial infections. Many providers prefer it over other treatment options. If you were diagnosed with a penicillin allergy in the past, it’s possible it was either a misdiagnosis or you lost sensitivity over time, meaning you might be missing out on a whole class of helpful medications. Scheduling an allergy test to verify that you do or don’t have a penicillin allergy will help you get the safe and effective care you need.
Call us at Midwest ENT Centre today to schedule your allergy test.
[1] Centers for Disease Control and Prevention. (n.d.). Clinical signs and symptoms of antibiotic allergy. https://www.cdc.gov/antibiotic-use/hcp/clinical-signs/index.html
[2] Patterson, R. A., & Stankewicz, H. A. (2023). Penicillin allergy. In StatPearls. StatPearls Publishing. https://www.ncbi.nlm.nih.gov/books/NBK459320/