Penicillin Allergies: Debunking Myths

Segment Description: Julie Ann Justo, PharmD, MS, BCPS-AQ ID, an assistant clinical professor at the University of South Carolina College of Pharmacy, and infectious diseases clinical pharmacy specialist at Palmetto Health Richland Hospital, Columbia South Carolina, discusses penicillin allergies and the SIDP Podcast: The Itch.

Interview Transcript (modified slightly for readability):

Some of the misconceptions about penicillin allergy that we discuss in the podcast — which was so much fun by the way, for anyone who's ever listened to a podcast it's actually really fun to record them too – but some of the misconceptions that we discussed in that specific podcast was number one that once allergic, always allergic.

So, we have many patients that come into the clinic or the hospital and of course one of the first questions they get asked during intake is ‘do you have any allergies?’ and of course they're going to say ‘oh yes I'm allergic to penicillin,’ or whatever beta lactam they were exposed to. One of the things that I think providers fail to do is dig a little bit deeper and discuss the reaction and the timing during their lifetime. For instance, if someone was told by their mother ‘oh you had a reaction to penicillin, you had a rash as a kid,’ well even if that was a type-one mediated reaction with IgE antibodies that were produced at the time, for many individuals, production of those antibodies will usually wane after about 10 year’s time.

Such that it's quite possible that if that occurred when they were 5 years old and now maybe they're 45 years old, it is quite possible that they've either received penicillin or another beta lactam and actually tolerated it, or we could set up a safe way for them to have a test dose of that medication or in some cases do skin testing which has been a wonderful tool for us.

So, I think that's one of the myths that we like to bust on a regular basis is: once allergic always allergic.

Some of the consequences that result from incorrect penicillin allergy labels are first and foremost it impacts the empiric and a microbial selection and the first antibiotics that patients will receive to treat an infection that they may have. So, one of the things that we very much educate our patients on is trust me, you don't want to be labeled as penicillin allergic unless you really are. And the reason why is because that whole family of beta lactam antibiotics on the whole are really the safest and most efficacious antibiotics that we have, and they are first-line recommendations for a wide variety of infectious syndromes such as pneumonia, urinary tract infections, skin and soft-tissue infections and so on.

And while there are alternatives that are unrelated and thus are unlikely to elicit an allergic response, in some cases they actually may be either more expensive they might not quite be quite as efficacious. They may actually have increased risk of toxicity or side effects and so depending on the case and what exactly is happening, it would probably be best if they weren't penicillin allergic that we move forward with a beta lactam. So, we work very hard to get all the details and nuances of the penicillin allergy history such that if we can safely deal able someone we will do so for their own benefit so that they can get the best antibiotic moving forward.