SOURCE: Trubiano JA, et al. JAMA 2017;318:82-83.
Although clinicians should be applauded for their perspicacity in identifying drug allergies among their patients, the literature suggests we have grossly overestimated the actual prevalence of penicillin allergies. Based on sophisticated diagnostic testing, only 1% of the U.S. population actually is allergic to penicillin, yet as many as 10% of Americans have been labelled as penicillin-allergic.
It is easy to understand how a rash appearing after a viral infection during which penicillin had been inappropriately administered might prompt the belief that the antibiotic was the culprit. Additionally, even when IgE-mediated reactions to penicillin occur, reactivity appears to wane over time, such that most patients who have manifested penicillin allergies will exhibit negative penicillin skin test reactions 10 years later. Additionally, these same individuals who become penicillin skin-test negative are reported to have minimal future risk of reacting to penicillin or other beta-lactam antibiotics.
In an era requiring more vigilant antibiotic stewardship, clarifying whether a patient who reportedly suffers from penicillin allergies actually still has that hyperreactivity through skin testing may allow us to be more focused in our choice of penicillins and cephalosporins.