Kimberly Blumenthal
Appearances
Freakonomics Radio
617. Are You Really Allergic to Penicillin?
Unless you happen to be allergic. Penicillin allergy was described immediately after penicillin was released, and it's the same with all drugs. You release new drugs, and we find patients that are allergic. But antibiotic allergy is misdiagnosed most of the time.
Freakonomics Radio
617. Are You Really Allergic to Penicillin?
When we have infections, we get rashes.
Freakonomics Radio
617. Are You Really Allergic to Penicillin?
Yeah, especially in children. Children get rashes when they have infections. Those infections are treated with antibiotics. There's misattribution of allergy.
Freakonomics Radio
617. Are You Really Allergic to Penicillin?
Absolutely. For years and years, we have had this idea that an infection requires antibiotics. And only like the past five, ten years, we've tried to pull back on that because of antibiotic resistance.
Freakonomics Radio
617. Are You Really Allergic to Penicillin?
Don't act too fast, right? I think it's good to be a really busy parent and not be on top of it and rushing them in right away.
Freakonomics Radio
617. Are You Really Allergic to Penicillin?
Yeah, and some people do it better than others. There are these fantastic discharge prescriptions that aren't actual prescriptions. Things like rest and drink plenty of water and Nana's chicken soup. Take Tylenol or Motrin for a fever. And then if things a week later are still in the same place or things worsen, then call me back and then we treat with antibiotics.
Freakonomics Radio
617. Are You Really Allergic to Penicillin?
I really was drawn to the idea of how important the choice of what drug was the key decision, what drug is right for this patient. I pretty immediately realized that regardless of what nonspecific garbage was listed on the allergy list, it really changed care. And I just got totally distracted as to like, does it need to change care? Why is there a two-tier system?
Freakonomics Radio
617. Are You Really Allergic to Penicillin?
If you have an allergy, you treat with this, but everyone else who doesn't have an allergy gets this. I realized that what we were calling allergy was mostly side effects.
Freakonomics Radio
617. Are You Really Allergic to Penicillin?
Something way too big to hammer in the nail. Some sort of mallet is like, you know, I don't do tools and hardware.
Freakonomics Radio
617. Are You Really Allergic to Penicillin?
Sure. Maybe could get the job done, but by kind of making a mess. Yeah.
Freakonomics Radio
617. Are You Really Allergic to Penicillin?
If I were to see something like five patients for this a week myself... And I've been doing it for over a decade. We're near 3,000 patients. I've seen probably 20 allergic.
Freakonomics Radio
617. Are You Really Allergic to Penicillin?
Yeah, they present to my clinic at the suggestion of their primary or their surgeon or themselves. Yeah, I would say it's probably been 3,000 patients that I've seen myself in. I know and remember two severe reactions. That's it. The rest have been rashes.
Freakonomics Radio
617. Are You Really Allergic to Penicillin?
No, and this is why we should be screaming from the rooftops is misdiagnosis. This is a missed diagnosis. Everyone has something on their chart that's wrong, and nobody is screaming about taking it off. We reconcile medicines every visit. I'm taking this. I'm not taking this. We try to take care to make sure what is in the chart is correct.
Freakonomics Radio
617. Are You Really Allergic to Penicillin?
This is something that is not ever addressed and is incorrect in the majority of people.
Freakonomics Radio
617. Are You Really Allergic to Penicillin?
We should be screaming from the rooftops. This is a misdiagnosis.
Freakonomics Radio
617. Are You Really Allergic to Penicillin?
We did an all-cause mortality study in a very nicely controlled observational study. 14% increased all-cause mortality. Wait a minute.
Freakonomics Radio
617. Are You Really Allergic to Penicillin?
There's avoiding antibiotic resistance, C. diff colitis, avoiding too long of hospital stays, avoiding surgical infections if you had needed an operation. And then there's avoiding other adverse events that result from a choice of antibiotic that is just more toxic and by its nature caused more renal failure or caused more diarrhea or whatnot.
Freakonomics Radio
617. Are You Really Allergic to Penicillin?
It's such a no-brainer. I mean, when you give me this description, what comes to mind is two people who have strep throat. Strep throat and a penicillinology label. One person gets penicillin. That's indicated for penicillin. Strep throat goes away. No long-term sequelae. They're fine. It was cheap. And then the other person gets a Z-Pak, azithromycin. And it doesn't fully go away.
Freakonomics Radio
617. Are You Really Allergic to Penicillin?
Then they call back and they get another antibiotic. Maybe this time they get a bigger antibiotic. And that causes some problem. They might get a tonsillar abscess. They get a quinolone, ciprofloxacin unnecessarily, or some other medication.
Freakonomics Radio
617. Are You Really Allergic to Penicillin?
We can evaluate for penicillin allergy with simple tests. And these simple tests need to be delivered to that 10 percent of America and reimbursed appropriately and taught to a non-specialist workforce. Could be a welcome to college visit, a welcome to Medicare visit,
Freakonomics Radio
617. Are You Really Allergic to Penicillin?
Just my health care system would be millions. If we evaluated penicillin allergy, delabeled the appropriate ones, we would save millions of dollars, just my health care system. So it must be in the billions.
Freakonomics Radio
617. Are You Really Allergic to Penicillin?
Yes. You'd save on adverse effect avoidance.
Freakonomics Radio
617. Are You Really Allergic to Penicillin?
Yes, and some of these adverse effects lead you to the emergency room and another hospitalization. You'd save on surgical infections, a tremendously costly thing.
Freakonomics Radio
617. Are You Really Allergic to Penicillin?
In our hospitals, without an allergist involved, there is sort of algorithmic care that can clear allergy in low-risk situations with just a protocol, just a little bit more observation. You're ready in the hospital. You're being observed.
Freakonomics Radio
617. Are You Really Allergic to Penicillin?
We do it when patients have infections. So we don't do it electively, like if you're there for something not related. But if you have an infection that an allergy is getting in the way of best care, we have a two-step drug challenge process. And as long as the patient's healthy enough to do that, we do it. So we give a small amount, watch the patient, give a full amount, watch the patient.
Freakonomics Radio
617. Are You Really Allergic to Penicillin?
And then if that's the drug that they need to be treated with, they just continue that drug right then and there.
Freakonomics Radio
617. Are You Really Allergic to Penicillin?
You would kill some people by accident. And in America, it's just a non-starter.
Freakonomics Radio
617. Are You Really Allergic to Penicillin?
Well, there's also this doctor, first do no harm, like the oath we take, and it feels wrong to just disregard allergy labels entirely.
Freakonomics Radio
617. Are You Really Allergic to Penicillin?
I can tell you with confidence that I was the first penicillin allergy grant that the NIH funded in 30 years. Whose area is it? Is it infectious disease? Is it allergy? It's multidisciplinary. Is it surgery? Is it obstetrics? Because penicillins are used by everybody. Dentists. It was very hard to know who takes ownership of something that crosses every single discipline.
Freakonomics Radio
617. Are You Really Allergic to Penicillin?
We were trying so hard. I was working with Thermo Fisher Scientific. They have developed a blood test panel, and they wanted to see if it worked in allergic individuals from America. We identified in the Boston area everyone that reacted to penicillin in front of our faces in the last few years. We sent them the blood of these individuals, and I think it picked up like three.
Freakonomics Radio
617. Are You Really Allergic to Penicillin?
It was like three of 20. It didn't pick it up yet.
Freakonomics Radio
617. Are You Really Allergic to Penicillin?
The conclusion was, well, they were allergic in the last 5, 10 years. Maybe they weren't allergic now. So I have to bring them back, retest them. And then these patients, they're like needles in haystacks, right? We combed the records of all Mass General Brigham to find these 22 penicillin allergics. We really need to say, OK, you reacted to penicillin in front of my face today.
Freakonomics Radio
617. Are You Really Allergic to Penicillin?
Grab your blood and then send it to be able to know that they were true positives.
Freakonomics Radio
617. Are You Really Allergic to Penicillin?
One of my mentors said to me, if you do your job well, you have no job. And I'm like, I just don't think that's going to happen. There's always something else. We need better tests now, back to the basic science in the lab. And then on the population level, we're thinking about implementing penicillin allergy evaluation in primary care.
Freakonomics Radio
617. Are You Really Allergic to Penicillin?
We just created a measure of delabeled patients in our healthcare system. And even just now that I can measure it, I can measure it in this clinic and that clinic, and I can see what types of interventions move the needle towards a higher percentage of delabeled patients.
Freakonomics Radio
617. Are You Really Allergic to Penicillin?
I think it's possible. And it's also possible that we could alter our drugs to be less allergenic.
Freakonomics Radio
617. Are You Really Allergic to Penicillin?
We'd have to know what metabolite of the drug is forming bonds in our body to make the allergen. And so it requires a lot of combined intelligence from different people.
Freakonomics Radio
617. Are You Really Allergic to Penicillin?
Yeah, I would stop happy if we have some sort of way that like everybody knows if they can or cannot have penicillin or any drug or they're going to be allergic or not. If we were able to correct the 30 million mislabels in just America, I'm happy. I'm retired.
Freakonomics Radio
617. Are You Really Allergic to Penicillin?
Nothing kills bacteria better than these drugs.
Freakonomics Radio
617. Are You Really Allergic to Penicillin?
I'm an allergist immunologist and clinical population level researcher at Mass General Hospital and Harvard Medical School.
Freakonomics Radio
617. Are You Really Allergic to Penicillin?
If your infection is sensitive to these drugs, they are the best drugs out there. From an adverse effect profile, they're also much more benign than other antibiotics.