Penicillin Allergy Is Associated with Longer Hospital Stays and Increased Antibiotic Use

Penicillin allergy is reported by roughly 10% of the U.S. population, but in a recent study in which patients who reported penicillin allergy were skin tested and given oral challenges, fewer than 10% were truly allergic (NEJM JW Gen Med Jul 11, 2013). This overreporting leads clinicians to prescribe other antibiotics, which may be more expensive, less efficacious, and more likely to cause adverse effects. Investigators conducted a retrospective study in which 51,582 “penicillin-allergic” patients admitted to Kaiser Foundation hospitals between 2010 and 2012 were compared with nonpenicillin-allergic controls.

During mean follow-up of 20 months, patients with penicillin allergy histories were significantly more likely to receive fluoroquinolones, vancomycin, and clindamycin than control patients, and they averaged 0.59 more total days in the hospital. Penicillin-allergic patients also had more resistant infections than controls: 23.4% more Clostridium difficile, 14.1% more methicillin-resistant Staphylococcus aureus, and 30.1% more vancomycin-resistant enterococci. During the 3-year study, the extra hospital days associated with penicillin allergy cost the health care system an estimated US$60 million.