About 10% of all patients in the United States have a penicillin allergy listed in their medical records. But in more than 90% of patients, that label is wrong—in many cases, either because a viral rash was mistaken for a penicillin allergy when the person was a child, or because earlier acute penicillin reactions have declined and disappeared over time (JAMA 2017;318[1]:82-83).
Patients labeled with penicillin allergies often receive non-preferred antibiotics, such as