Theresa MacPhail
Appearances
Freakonomics Radio
617. Are You Really Allergic to Penicillin?
He used to fight with people to get them to recognize that their issue is food allergy. And now he fights with people to get them to recognize that their issue is not food allergy.
Freakonomics Radio
617. Are You Really Allergic to Penicillin?
Medical anthropology is looking at all the social and cultural factors involved in healthcare systems. We think about how all those beliefs and politics and economics, how all of that factors into the choices people make about their health and how they view their health.
Freakonomics Radio
617. Are You Really Allergic to Penicillin?
I'm associate professor of science and technology studies at Stevens Institute of Technology.
Freakonomics Radio
617. Are You Really Allergic to Penicillin?
That's been a puzzle as to why an immune cell will take a look at something that is otherwise harmless and decide that it's not and do it after sometimes years of tolerating it just fine. And suddenly now it's a problem.
Freakonomics Radio
617. Are You Really Allergic to Penicillin?
My father died of a bee sting. He died from an anaphylactic reaction to bee venom. He had had a reaction in the past, but it was fairly mild, just swelling at the site. That's mostly what happens to anyone who gets stung by a venomous insect. And he died on the second sting.
Freakonomics Radio
617. Are You Really Allergic to Penicillin?
We really don't know how many times he was stung because he was a Vietnam vet, so there's a chance that he was stung prior to that. And I got curious about my own susceptibility to such things. Years later, I was diagnosed with allergies, but I am one of the rare people that do not react to skin or blood tests. I have low levels of IgE, the antibody that is driving the allergic response.
Freakonomics Radio
617. Are You Really Allergic to Penicillin?
So there's no way to tell what I'm allergic to, except that clinically you can see the signs and symptoms that I am allergic to something.
Freakonomics Radio
617. Are You Really Allergic to Penicillin?
I think, based on my years of detective work, that I'm allergic to grass and probably ragweed and maybe dust mites.
Freakonomics Radio
617. Are You Really Allergic to Penicillin?
Oh boy, how much time do we have? This is part of the problem. There's a lot of confusion about what an allergy is and isn't. The easiest answer I can give you is that an allergy is when your body responds to something that is otherwise harmless and triggers an immune response. If your immune cells are not involved in the response, then it is not an allergy.
Freakonomics Radio
617. Are You Really Allergic to Penicillin?
The classic example is milk allergy versus milk intolerance. On the surface, if you have a mild milk allergy, it's going to look the same, perhaps an upset stomach, feeling kind of gross, some gassiness. But the difference is with the intolerance, there's something else going on. In this case, you're not able to digest lactose because you lack an enzyme.
Freakonomics Radio
617. Are You Really Allergic to Penicillin?
But it's producing symptoms that would seem familiar to someone whose immune cells, whose T cells and B cells are producing antibodies and attacking that milk protein. Except that the allergy can, you know, escalate. You can get a skin rash, you can get wheezing, and you can end up in the ER with a full-on anaphylactic event. That's not going to happen with intolerance.
Freakonomics Radio
617. Are You Really Allergic to Penicillin?
But if you have mild forms of this, you're going to be confused and you might just assume that you have an allergy. And the only way to know for certain is to see an allergist. The problem there is we don't really have enough of them. They're specialists and you need a referral to see one. And so a lot of people are out there self-diagnosing.
Freakonomics Radio
617. Are You Really Allergic to Penicillin?
We think as far as we can tell that they are rising, but it's complicated. We know that rates of asthma and hay fever started to rise post-World War II, like 1950s, 1960s, and continued right up until the 1990s. And now they seem to have been flattened. But what has been rising in the wake of that are rates of food allergies. We know this because of several reasons.
Freakonomics Radio
617. Are You Really Allergic to Penicillin?
One is you can look at ER visits. You can see when someone is showing up with asthma or with a rash, like a very bad eczema eruption, or they are having anaphylaxis. The other thing that we can track is EpiPen or adrenaline prescriptions. Those raised three to four times from the 1990s to around 2018, 2019.
Freakonomics Radio
617. Are You Really Allergic to Penicillin?
It's bad. It's one of the reasons I can't tell you how many people actually have an allergy.
Freakonomics Radio
617. Are You Really Allergic to Penicillin?
Right. So in the 1980s, this is after the massive rise of asthma, we're starting to see food allergies. An epidemiologist was curious about this and started collecting data on families and realized that older siblings seem to have more allergic disease than younger siblings. The theory was that older siblings bring home colds and track in bugs to expose their younger siblings.
Freakonomics Radio
617. Are You Really Allergic to Penicillin?
And there was something about that earlier exposure that had somehow protected these younger siblings. It was called the hygiene hypothesis. That has morphed over the years to what is now called the old friends hypothesis. which is nice, isn't it? That's a nicer way to put it.
Freakonomics Radio
617. Are You Really Allergic to Penicillin?
That there's something about getting the right exposures to the right bacteria or the right viruses and fungi that will help train our immune system. You're born with a novice, a naive immune system that hasn't seen anything.
Freakonomics Radio
617. Are You Really Allergic to Penicillin?
And you're born with an innate immune system, which means there are things online from the very beginning that just act as a brute force response to anything that threatens the individual. And then you have an adaptive immune system, which involve your T cells and your B cells and your antibodies that remember the things that you've been exposed to. And so the theory is those have to be trained.
Freakonomics Radio
617. Are You Really Allergic to Penicillin?
And they have to be trained in the right order. And they have to be exposed to the same types of bugs, microbes that they would have been evolving with for millennia. The theory is that we've changed so much that some of those are missing. It has confused our immune system to the extent that you're seeing more allergic disease because you're not getting the training.
Freakonomics Radio
617. Are You Really Allergic to Penicillin?
It's basically advocacy. And at the forefront of that is a group called FAIR, which is Food Allergy Research and Education. They're privately funded and run by a group of parents. When I started researching the book, one of the first people I sat down with was Helen Jaffe, her and her husband David.
Freakonomics Radio
617. Are You Really Allergic to Penicillin?
are some of the founding members of FAIR, and they also have helped to fund the Jaffe Center at Mount Sinai for food allergy research. When they started the foundation, it was because two of their children had quite severe food allergies, but it was at a time where no one was doing this. They live here in New York City, and they had to take the train down to Johns Hopkins to see Dr. Hugh Sampson.
Freakonomics Radio
617. Are You Really Allergic to Penicillin?
He's a renowned food allergist and researcher, and he has been doing this for over 40 years. But at the time, there were maybe half a dozen people focused on food allergy.
Freakonomics Radio
617. Are You Really Allergic to Penicillin?
And so initially, Helen told me that their focus was really on education and research funding to try to figure out what was going on, why the rates seemed to be rising, figure out more about the biological mechanisms that drove this response. I spoke with Dr. Hugh Sampson now, we're talking about years later, and he said he used to
Freakonomics Radio
617. Are You Really Allergic to Penicillin?
fight with people to get them to recognize that their issue is food allergy. And now he fights with people to get them to recognize that their issue is not food allergy.
Freakonomics Radio
617. Are You Really Allergic to Penicillin?
No, it's bad. It's bad. I mean, diagnostics are one of the sticking points. It's one of the reasons I can't tell you how many people actually have an allergy. Because we're stuck with primarily the skin tests, which were invented in the late 1800s by a UK physician, Dr. Charles Blackley. Wait, the late 1800s? Yes.
Freakonomics Radio
617. Are You Really Allergic to Penicillin?
And if I exhumed him and revived him, he would have no problem giving a skin test today.
Freakonomics Radio
617. Are You Really Allergic to Penicillin?
That is the better situation. It's around 95 percent certain if you do not respond that you are not going to respond in real life.
Freakonomics Radio
617. Are You Really Allergic to Penicillin?
Yes, that's good news. That's why we still use them, because it's almost like a differential diagnosis. We can rule some things out.
Freakonomics Radio
617. Are You Really Allergic to Penicillin?
In my grandmother's case, we know because she was in the hospital and had an actual skin eruption and reaction to penicillin. I honestly don't know about my aunt. Sorry if she's listening to this. Because to my knowledge, she's never been tested. So I don't know. She does avoid them, though. At the end of the day, I suppose it doesn't matter.