Clinic helps adults clarify true status of penicillin allergySep. 27, 2018, 9:09 AM
by Bill Snyder
Two years ago when she was given a type of penicillin to fight off bacterial pneumonia, Kelly Cummins developed a rash, itching and shortness of breath. Suspecting she was having a reaction to the life-saving medication, her doctor stopped the penicillin and substituted a different class of antibiotic.
Cummins recovered but now she had a warning label in her medical record: Never again would she be given drugs in the penicillin family for fear they would trigger a life-threatening reaction.
Yet she suspected that her symptoms may have been caused by her illness, not by the medication. She knew drugs in the penicillin family are more effective, less expensive and have fewer side effects than other antibiotics.
So earlier this month, Cummins underwent skin testing at the drug allergy clinic at Vanderbilt University Medical Center. The results were negative. The doctors then gave her a dose of amoxicillin, which she tolerated uneventfully, to prove she was not at risk for immediate allergy with future penicillin treatments.
“It’s imperative to know what you are and what you are not allergic to,” said Cummins, the mother of two children from Franklin, Tennessee. “I want to be able to better inform my doctors if I ever become ill again.”
Penicillin “labeling” is a big problem, said clinic director Elizabeth Phillips, MD, an internationally known expert on severe adverse drug reactions.
An estimated 10 percent of the U.S. population carries a penicillin allergy label. Most patients are given this allergy label in childhood; 75 percent by age 3. Yet when tested today fewer than 5 percent of adults are truly allergic. The rest presumably outgrew their allergies or were never allergic to begin with.
Overuse of alternative, broad-based antibiotics contributes to the development of drug-resistant bacteria including Clostridioides difficile, which can cause life-threatening infections and can spread to other patients. The inability to give penicillin to patients in the hospital results in a higher incidence of drug-resistant infections, longer hospital stays and higher costs.
Phillips, the John A. Oates Chair in Clinical Research and professor of Medicine, Pharmacology and Pathology, Microbiology and Immunology in the Vanderbilt University School of Medicine, is promoting National Penicillin Allergy Day on Sept. 28 to raise awareness of the problem.
With Cosby Stone Jr., MD, MPH, a postdoctoral research fellow in Allergy/Immunology at VUMC, she developed an interactive, online questionnaire that can determine whether patients are at high, medium or low risk of having an allergic reaction to penicillin.
In the clinic, the questionnaire’s findings are validated by skin testing — injecting a tiny bit of penicillin under the skin to see if a localized rash indicative of an allergy appears — and by giving patients an oral dose of the drug under close supervision.
Sixty percent of clinic patients are correctly identified by the questionnaire as being at low risk; fewer than 1 percent have a positive follow-up skin test.
Now Stone, Phillips and their colleagues are preparing a pilot study of hospitalized patients at VUMC to begin in early 2019. The goal is to use this questionnaire to identify low-risk patients in the hospital whose labels can be safely removed.
“We want to put a program in place that will allow penicillin allergy to be tackled efficiently across the entire Vanderbilt enterprise,” Stone said. “We want to identify the low-risk patients for safe challenges and label removals at the point of care, and then the higher-risk patients can be referred to us for testing.”
“This study will develop the evidence base to make this approach the standard of care,” Phillips added, “and each year help thousands of patients at Vanderbilt alone to remove their penicillin allergy labels.”
Phillips and Stone are supported by the National Institutes of Health. The planned inpatient study was developed with support from Learning Healthcare System Platform of the Vanderbilt Institute of Clinical and Translational Research (VICTR).
“Because a project of this type requires cooperation and collaboration between physicians, clinic staff, medical records, health informatics, biostatistics and clinical research professionals, it is an ideal project for VICTR’s Learning Healthcare System Platform,” said VICTR director Gordon Bernard, MD, VUMC’s Executive Vice President for Research.
“This platform brings together research and clinical professionals for the purpose of conducting robust scientific research embedded in clinical operations,” said Bernard, who also is the Melinda Owen Bass Professor of Medicine and Senior Associate Dean for Clinical Research in the School of Medicine.
For more information about penicillin allergy de-labeling at VUMC, call 615-936-2727.