About 10 to 15% of hospitalized patients have penicillin
allergy in their medical record, but studies have shown that more than
95% are not really allergic.
Over-reporting of penicillin allergies has a
negative impact on patient care, as the alternative drugs often used are
less effective, more toxic and can both leave patients vulnerable to
dangerous C. difficile infection and increase antibiotic resistance in
‘Use of penicillin allergy skin tests or a computerized support tool safely increases the use of penicillin and penicillin-related antibiotics in inpatients.’
The need to address over-reported penicillin allergy has
been widely acknowledged, but how to do that has remained unclear.
Massachusetts General Hospital (MGH) and Brigham and Women's Hospital
(BWH) investigators have developed two approaches to increasing the use
of penicillins and cephalosporins - highly effective antibiotics that
are not as problematic as many alternatives - in hospitalized patients
previously believed to be allergic to penicillin.
Their report, which
has been published online in the Journal of Allergy and Clinical Immunology
describes how both tested protocols - use of penicillin allergy skin
tests or a computerized guideline/decision support tool - safely
increased the use of penicillin and penicillin-related antibiotics in
"This study offered a unique opportunity to examine what strategy
best serves inpatients who have this listed allergy," explains co-lead
author Paige Wickner of the BWH Division of Rheumatology, Immunology and Allergy and the Department of Quality and Safety.
Over a two-year period - June 2014 to June 2016 - the
investigators compared three approaches to treating BWH inpatients who
needed antibiotic treatment and had a recorded penicillin allergy.
During the first five months, patients on the medical service received
standard of care treatment, with testing via either skin test or test
dosing conducted only after referral by the primary care team and
consultation with an allergy specialist.
During the next seven months, inpatients with a recorded penicillin
allergy who needed antibiotic treatment were screened for skin-test
eligibility. Those with a history of more serious allergic reactions or
those taking drugs that could interfere with skin testing were
ineligible, and testing also required consent of the patient and the
care team. Patients whose skin test was negative and safely tolerated an
oral dose of amoxicillin - a form of penicillin in the same beta-lactam
antibiotic class as cephalosporins - were determined not to be
During the third seven-month period, physicians had access to a
computerized treatment guideline and decision support system, which -
based on details of the reported allergic reaction, such as whether the
patient experienced a rash, fever or joint pain - categorized the
reaction as follows:
- very low risk - full dose of penicillin or cephalosporin
- low risk - reduced test dose of penicillin or cephalosporin
- medium/high risk - consult with an allergy specialist
- serious reaction - avoid penicillin or cephalosporin.
Due to logistical issues, including schedule coordination and the
inability to conduct tests on more than one patient at a time, only 43
of the 179 patients (24%) who would have been eligible for skin
testing actually had the test. But while that did not result in a
significant increase between the standard-of-care and skin-test periods
in the overall percentage of those receiving penicillin or
cephalosporin, among patients who had the test, the likelihood of
receiving the more favorable prescription increased almost six times. In
fact, none of the skin-tested patients proved to have a penicillin
allergy, and they also had more than double the chance of being
discharged with a penicillin or cephalosporin prescription.
During the treatment guideline/decision support period, the
likelihood that patients would receive a more favorable antibiotic
prescription almost doubled over the standard of care period. Among the
providers caring for the 199 medical patients during this period, 112
completed the decision support protocol and there were almost 300 unique
webpage views of the guideline, which was accessible both at all
hospital desktop computers and through mobile devices connecting to the
secure hospital intranet. No adverse reactions occurred during either
the standard-of-care or skin-test periods, and only one patient had a
mild reaction - an itchy skin rash - to an amoxicillin dose after a
negative penicillin skin test during the treatment guideline/decision
Kimberly Blumenthal of the Division of Rheumatology, Allergy and Immunology, the Medical Practice Evaluation Center, and the Lawrence Center for Quality and Safety at MGH, co-lead and corresponding author of the JACI
paper notes that the guideline/decision support tool was not
integrated into the electronic health record during the study period and
that, as the tool becomes more available, it may have an even greater
effect on antibiotic prescriptions.
The tool has now been adopted at
MGH, BWH, Newton-Wellesley Hospital, Brigham and Women's Faulkner
Hospital and North Shore Medical Center - all members of Partners
HealthCare System. Such a tool also could be useful for hospitals with
limited ability to adopt a skin testing protocol or lack of access to
staff allergy specialists.
"We found that addressing penicillin allergy by either method could
lead to an overall improvement in antibiotic choice for these patients,"
Blumenthal says. "We don't want to discourage any method of evaluation
because even thinking about whether a patient's penicillin allergy is
true could lead a provider to make a different management decision. Even
here at MGH, we estimated that skin testing all patients with recorded
penicillin allergy would be impractical without a significant staff
increase or technological guidance."
Wickner adds, "In our Partners system alone, we have more than
200,000 patients who carry this listed diagnosis in the electronic
medical record. It is exciting to have safe and effective systems in
place to improve the care of these patients when they are hospitalized."