Two Reasons You’re Probably Not Allergic to Penicillin Anymore

Jessica Stern, MD, MS

If you have a penicillin allergy, here’s a surprising fact: there’s a very good chance you can take it anyway. According to UR Medicine allergist Jessica Stern, MD, MS, new research shows that up to 90 percent of people labeled as allergic to penicillin can take it safely.

“Many people are living with an outdated diagnosis,” said Stern. “With the right evaluation and testing, you can potentially have this label removed, making it easier to receive more effective treatments when you need antibiotics.”

If you’ve been told you’re allergic in the past, it’s time to talk to your doctor about scheduling a penicillin allergy evaluation.

Can you outgrow a penicillin allergy?

There are two main reasons why people still have a penicillin allergy label even when they might not be truly allergic:

1. Misdiagnosis in Childhood: Often, getting labeled allergic can come from having symptoms, like a rash, that are actually from the illness rather than the antibiotic.
2. Outgrowing the Allergy: Studies show that up to 85 percent of people who were truly allergic as children grow out of it in five to ten years. However, it rarely gets updated in people’s medical records.

Why it’s important to get a penicillin allergy test

When you take a trip to the doctor's office or hospital and need antibiotics, if you’re labeled allergic to penicillin, you’re likely to receive a less effective or more costly antibiotic. These alternatives can have more side effects and increase the risk of complications, like infection. This can lead to longer stays in the hospital and higher medical costs.

How to get tested for penicillin allergy

Talk to your doctor about getting tested.

• Who to Call: Ask your primary care physician or a medical professional about requesting a penicillin allergy evaluation. Or you can call the URMC Allergy Clinic at 585-486-0930. There are clinic locations across the greater Rochester region.
• The Evaluation: It involves a careful history and may include a skin test and an “oral challenge” where you take a small dose under medical supervision. Patients with low-risk history may only require a test dose followed by observation.
• What’s Next: If the results show you’re no longer allergic, your doctor can update your records to remove the label.