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Good News for Penicillin and Flu Shot Allergic Reactions

Apr 20th 2020

What are the hot topics and clinical trends in internal medicine that clinicians are talking about? Two expert internists took some time recently to discuss their thoughts on these issues.

Donald L. Deye, MD, FACP, is a general internist who has practiced for over 30 years at Cambridge Medical Center in Cambridge, MN. He is also Chief Medical Officer for Oakstone, and host of the acclaimed MKSAP Audio Companion. Timothy Leigh Rodgers, MD, is an internal medicine specialist practicing in Santa Barbara, CA.

Penicillin Allergy: Really?

Dr. Deye: Let’s talk about penicillin allergy. Many, many of our patients have penicillin allergy listed in their charts. Turns out that the vast majority of these patients really do NOT have an actual allergy to penicillin. Recently investigators performed skin testing on over 300 people who said that they were allergic to penicillin. Out of these roughly 300 patients, only four were actually allergic to penicillin. The rest had an event that was interpreted as an allergic reaction, but actually was not.

Dr. Rodgers: This means that we should consider doing allergy skin testing for patients listed as having a penicillin allergy but could benefit from the use of penicillin. Only about 1 percent of these patients will be found to have a true allergy. This could be a game changer when treating certain infections.

Egg Allergy? Flu Vaccine Okay

Dr. Rodgers: Turns out that there is no need to ask patients about egg allergies before giving the flu vaccine. Patients with egg allergy actually have no increased risk for an adverse response to the flu shot than in patients without egg allergy.

Dr. Deye: Right. People who are allergic to eating eggs will not be adversely affected by the trace amounts of egg protein in the flu shot. One less thing to worry about.

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