Most Aren't Really Allergic to Antibiotics, Updated Guidelines Say

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At the recent American Academy of Allergy, Asthma & Immunology (AAAAI) annual meeting, the presidential plenary session included several talks on drug allergy, highlighted by outgoing AAAAI president David A. Khan, MD, a professor of internal medicine and pediatrics at the University of Texas Southwestern Medical Center in Dallas, who summarized key points from a practice parameter update from an expert workgroup he chaired.

In this MedPage Today video, Khan discusses a few of the guideline updates for antibiotic allergy.

Following is a transcript of his remarks:

This new guideline, which was published in December of 2022 is an update from our prior one from 2010. And there's been a lot of major advances. And even though this guideline is written kind of with the focus of allergy immunology specialists, many of our recommendations apply to a very broad audience, particularly I would say with the updates for antibiotic allergy.

So some of the key things that we are suggesting in this is related to penicillin allergy especially. The fact that penicillin allergy label is the most common drug allergy label in the health record. And we used to think that about 10% of people who had a history of penicillin allergy when tested would be positive. Now that number is less than 5%, maybe even 1%. So most people who carry this label aren't really allergic. So that's one thing.

But more importantly, and this is something that we've learned in the last few years, is having that penicillin allergy label comes at a cost to the patient. So there's morbidity associated with it. They get treated with more broad spectrum antibiotics that may not work as well. And also they have higher rates of MRSA [methicillin-resistant Staphylococcus aureus], VRE [vancomycin-resistant enterococci] infections, C. difficile, they stay in the hospital longer. There's even increased mortality. So there's a lot of bad things that happened just from having that label. And since most people aren't allergic, we're really encouraging providers, healthcare professionals, to refer patients to get this addressed.

And now the testing has gotten even simpler for most patients. Previously when we evaluated patients for penicillin allergy, we'd say, well, you always needed skin testing. Now, that's probably the minority of patients that need skin testing.

And for children especially, a simple, what we call a "graded challenge." We give them a small dose of some of a penicillin called amoxicillin, we watch them for a few minutes, then we give them the larger dose, and then we can say you're not allergic. And that's been shown now in recent studies to be very safe in over 8,000 children.

Now, optimistically, what we'd like to see is that this go outside of the allergy arena and other primary care doctors doing this. But I think most primary care physicians are not quite ready to be doing this yet, and that's okay. We need to kind of build that confidence, et cetera. But I think definitely they can refer to get patients what we call "delabeled," remove that penicillin allergy label.

The other important message that I wanted to discuss is relating to cross-reactivity between penicillin and other antibiotics. And because the penicillin allergy label is so common, they come into the hospital and now the doctors are like, well, is it safe to receive these other similar antibiotics like cephalosporins? And now our message is, if someone has a history of penicillin allergy, that's not anaphylactic, they can take any cephalosporin. And that's an important message that needs to get out there. So they don't need any testing, they can get any cephalosporin.

For the rare patients that truly are anaphylactically sensitive to penicillin, they can get other cephalosporins that are just not related to the penicillin that they're allergic to. And so, where this comes up oftentimes is for surgery where the recommended premedication is cefazolin. And even patients who are anaphylactically sensitive to penicillin can receive cefazolin. So pretty much anybody with the penicillin allergy can receive cefazolin. And that again, will have a lot less consternation and issues for orthopedic surgeons, anesthesiologists, et cetera.

So I would say those are the main messages that I think, resonate widely with the broader audience.

  • Greg Laub is the Senior Director of Video and currently leads the video and podcast production teams. Follow

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