If you say that you're allergic to penicillin— a narrow-spectrum antibiotic that, for many bacterial infections, is still considered to be a "wonder drug"—your doctor won't prescribe it. Once you write it on those forms in the waiting room, or tell your pharmacist, "penicillin allergy" becomes part of your permanent medical record.
Yet a growing body of evidence suggests that most people who say they're allergic to penicillin are, well, wrong. In a recent study published in Journal of Allergy & Clinical Immunology, nearly 90 percent of patients who had "penicillin allergy" listed on their medical charts were found to actually have no such allergy at all.
"There's this problem— what you could consider an epidemic—of people labeled with unverified penicillin allergy. It's the number one drug allergy that's listed in patients' records," Dr. Dave Kahn, a professor at the University of Texas Southwestern Medical Center and co-author of the study, told The Daily Beast. Over one in 10—up to 15 percent—of Americans has a reported penicillin allergy. That's more than the number of adults in the U.S. who have hay fever (7.8 percent), and the number of children under age three who have food allergies (8.0 percent).