Penicillin is the most common drug "allergy" noted at hospital admission, although
it is often inaccurate.
We sought to determine total hospital days, antibiotic exposures, and the prevalence
rates of Clostridium difficile, methicillin-resistant Staphylococcus aureus (MRSA),
and vancomycin-resistant Enterococcus (VRE) in patients with and without penicillin
"allergy" at hospital admission.
We performed a retrospective, matched cohort study of subjects admitted to Kaiser
Foundation hospitals in Southern California during 2010 through 2012.
It was possible to match 51,582 (99.6% of all possible cases) unique hospitalized
subjects with penicillin "allergy" to 2 unique discharge diagnosis category-matched,
sex-matched, age-matched, and date of admission-matched control subjects each. Cases
with penicillin "allergy" averaged 0.59 (9.9%; 95% CI, 0.47-0.71) more total hospital
days during 20.1 ± 10.5 months of follow-up compared with control subjects. Cases
were treated with significantly more fluoroquinolones, clindamycin, and vancomycin
(P < .0001) for each antibiotic compared with control subjects. Cases had 23.4% (95%
CI, 15.6% to 31.7%) more C difficile, 14.1% (95% CI, 7.1% to 21.6%) more MRSA, and
30.1% (95% CI, 12.5% to 50.4%) more VRE infections than expected compared with control
A penicillin "allergy" history, although often inaccurate, is not a benign finding
at hospital admission. Subjects with a penicillin "allergy" history spend significantly
more time in the hospital. Subjects with a penicillin "allergy" history are exposed
to significantly more antibiotics previously associated with C difficile and VRE.
Drug "allergies" in general, but most those notably to penicillin, are associated
with increased hospital use and increased C difficile, MRSA, and VRE prevalence.
Copyright © 2013 American Academy of Allergy, Asthma & Immunology. Published by Mosby,
Inc. All rights reserved.