Most Patients Aren't Actually Allergic to Penicillin

November 11, 2014
Rachel Lutz

Many patients who claim to have penicillin allergies may not actually be allergic to the antibiotic.

Many patients who claim to have penicillin allergies may not actually be allergic to the antibiotic, according to 2 studies presented at the American College of Allergy, Asthma and Immunology (ACAAI) Annual Scientific Meeting held November 6-10, 2014, in Atlanta, Georgia.

Patients who believe they are allergic to penicillin are given alternate antibiotics prior to surgery in order to ward off infection, but those alternatives can be more toxic, more expensive, and less effective. Furthermore, they are limited due to patient resistance.

In the first study, 384 patients had been previously told that they were allergic to penicillin, but after undergoing testing, the majority (94%) tested negative for penicillin allergy. According to the authors, once patients learn whether they are truly allergic to penicillin, they can be given more effective, more appropriate, and less resistant treatment prior to their surgeries.

“A large number of people in our study who had a history of penicillin allergy were actually not allergic. They may have had an unfavorable response to penicillin at some point in the past, such as hives or swelling, but they did not demonstrate any evidence of penicillin allergy at the current time,” said lead study author Thanai Pongdee, MD, in a press release. “With that in mind, their doctors prescribed different medications prior to surgery.”

Similarly, the second study used skin testing in 38 people who claimed they were allergic to penicillin, in order to determine whether such testing could help reduce the cost of expensive alternative antibiotics. Of those examined, every patient tested negative for penicillin allergies, after which the medical center altered the medications for 29 patients. The researchers found those antibiotic changes significantly lowered the prescription costs for those patients.

“When you are told you have an allergy to something, it's important to be seen and tested by an allergist, who has the specialized training needed for accurate diagnosis and treatment,” said James Sublett, MD, ACAAI president-elect, in the statement. “If you're truly allergic to a medication, your allergist will counsel you on an appropriate substitute.”’