Penicillin "allergy" label linked to longer hospital stays

A penicillin "allergy" label adversely affects the quantity and quality of healthcare in hospitalized patients, according to a study in the March issue of the Journal of Allergy and Clinical Immunology. The penicillin allergy label is the most common drug "allergy" listed in medical records during hospital admissions.

It is has been reported that of the 30 million U.S. patients reporting as penicillin allergic, 28.5 million actually are not. That means up to 19 out of 20 patients who think they are allergic to penicillin are misinformed. Antibiotic costs for patients reporting penicillin allergies are up to 63% higher.

Eric M. Macy, MD, and Richard Contreras, MS, of the Kaiser Permanente San Diego Medical Center, analyzed the Kaiser Foundation hospitals' electronic medical records over a three-year period, and found that about 11% of those admitted carried a penicillin "allergy" label. The study looked at more than 51,000 patients admitted to Kaiser Foundation hospitals in Southern California from 2010 through 2012.

“A penicillin ‘allergy’ history, although often inaccurate, is not a benign finding at hospital admission,” said Dr. Macy. “Subjects with a penicillin ‘allergy’ history spend significantly more time in the hospital. These subjects are also exposed to greater risk of infection and significantly more antibiotics previously associated with Clostridium difficile and vancomycin-resistant enterococci [VRE] infections.”

These adverse events occur because penicillin "allergic" patients are given more broad-spectrum antibiotics, including ciprofloxacin, vancomycin, clindamycin, and third- or greater generation cephalosporins.  Previous work by the Kaiser Foundation has shown than less than 5% of individuals who carry a history of penicillin "allergy" are truly allergic.

“An inaccurate penicillin ‘allergy’ record causes significant morbidity because it dramatically changes the types of antibiotics used toward those with more severe side effects,” Dr. Macy said. “All hospitalized patients with a history of penicillin ‘allergy’ should undergo penicillin skin testing and native penicillin and then if the skin test is negative have an oral amoxicillin challenge and 1 hour of observation.”

The study was funded by ALK.