Allergies have been documented in historical records dating as far back as 2,400 years ago, when Hippocrates wrote about “hostile humors” in some people who suffered badly after eating cheese. But why do we experience them to begin with? What even is an allergy? Are allergies on the rise? And why are some mere nuisances, while others are deadly?

This episode is a roundup of allergy stories—from the mundane to the frightful—and a round up of allergy questions we’re asking Dr. Theresa MacPhail, author of Allergic: Our Irritated Bodies in a Changing World, to answer for us.

Featuring Beni Osei Duker, Theresa MacPhail, Dwayne Smith, and Lily Ko.

Theresa MacPhail’s dad, James MacPhail, on duty in Vietnam. Photo courtesy of Theresa MacPhail.

ADDITIONAL MATERIALS

Check out Theresa MacPhail’s book, Allergic: Our Irritated Bodies in a Changing World.

Read up on the different hypotheses on why we get allergies in the first place:

Learn about the history of the EpiPen.

The EpiPen, or epinephrine auto-injector, was invented in the 1970s, but the use of epinephrine to treat allergies goes further back. Credit: Intropin on Wikimedia Commons (CC BY 3.0)

SUPPORT

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CREDITS

Host: Nate Hegyi

Reported, produced, and mixed by Felix Poon.

Edited by Taylor Quimby.

Our staff includes Justine Paradis, Marina Henke, and Kate Dario.

Executive producer: Taylor Quimby

Rebecca Lavoie is NHPR’s Director of On-Demand Audio

Music by Blue Dot Sessions, Particle House, and Caro Luna

Our theme music is by Breakmaster Cylinder.

Outside/In is a production of New Hampshire Public Radio

Submit a question to the “Outside/Inbox.” We answer queries about the natural world, climate change, sustainability, and human evolution. You can send a voice memo to outsidein@nhpr.org or leave a message on our hotline, 1-844-GO-OTTER (844-466-8837).

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Audio Transcript

Note: Episodes of Outside/In are made as pieces of audio, and some context and nuance may be lost on the page. Transcripts are generated using a combination of speech recognition software and human transcribers, and may contain errors.

Nate Hegyi: Hey, this is Outside/In, I’m Nate Hegyi, and it is officially spring. You can probably tell, my voice is kind of crackly, my nose is stuffy, my eyes are watery.

That’s because it’s also allergy season.

[MUX IN: Coulis Coulis, Blue Dot Sessions]

Taylor Quimby: Are you allergic to anything?

Kelly Mahoney: I’m kind of allergic to peanuts

Dan Tuohy: I have a shellfish allergy

Michelle Liu: Um, I think it depends on the year

Dan Tuohy: Beginning of the end of lobster for me

Nate Hegyi: So in honor of hives, the sneezing, the itching… our executive producer Taylor Quimby asked folks around the NHPR office what people are allergic to.

Emily Quirk: I have an allergic reaction to an antibiotic called Cipro.

Mara Hoplamazian: I didn’t know that I was allergic to anything until I moved to New Hampshire.

Taylor Quimby: So like, seasonal fall, spring kind of thing?

Mara Hoplamazian: Yeah

Jackie Harris: I used to be really allergic to poison ivy. I’m actually physically itching right now thinking about it.

Taylor Quimby: Are you allergic to anything?

Jason Moon: Not that I know of. I feel like I’m at the doctor’s office.

Taylor Quimby: So you’ve never taken Zyrtec?

Jason Moon: No, I don’t think so.

Taylor Quimby: Allegra?

Jason Moon: No.

Taylor Quimby: Claritin?

Jason Moon: No.

Taylor Quimby: Okay you can’t answer any of my follow ups so I’m moving on.

Nate Hegyi: So what did we learn from this? Well, Allergies are kind of mysterious. Some people get ‘em. Some people don’t.

Sometimes they’re just merely obnoxious… and sometimes they’re deadly serious.

Beni Osei Duker: once my family went to watch a show at the Kennedy Center in DC and I got some kind of sandwich from the stand there that had something I was allergic to in it.

Nate Hegyi: This is Beni Osei Duker (BEH-nee OH-say DOO-ker), a friend of producer Felix Poon.

Beni Osei Duker: So I'm sitting in my chair. It's completely dark in the room and I'm feeling itchy in my throat. So I'm like, okay, I'm gonna put the sandwich down, but I'll probably be fine. I can make it through the show.

By the time we get to intermission, I say like, guys, I think I ate something I'm allergic to. I don't feel so good. I go into the bathroom and my face is puffed up, swollen. My skin is bumpy everywhere. When I scratch it, it feels like scratching leather.

And I pop back out of the bathroom. And my mom saw me and was like, oh my God. And we she takes me into the car. We drive to the closest Wegmans to pick up Benadryl on our way to the hospital, and on the way into the Wegmans, I pass out in the parking lot.

[MUX IN: Capering, Blue Dot Sessions]

<<NUTGRAPH>>

Nate Hegyi: This is Outside/In. I’m your host Nate Hegyi. And today on the show, the third and final episode in our special miniseries “Things that Can Kill You”. We’ve learned about poison. We’ve talked about venom.

Today we’re looking at allergies, and contemplating its many existential mysteries.

Mara Hoplamazian: I feel like I have so many questions about allergies. Like where do they come from?

Dan Tuohy: As you get older do allergies get worse?

Jackie Harris: So I’m really curious if people grow out of allergies

Mara Hoplamazian: Also does taking bee pollen actually work?

Nate Hegyi: Plus… some wild stories of reactions gone wrong, and allergies run amok.

Stay tuned

[MUX SWELL AND OUT]

<<FIRST HALF>>

Nate Hegyi: I want to start with another allergy story.

And it comes from our guest for this episode: Anthropologist Theresa MacPhail.

She was working on a book about allergies when she turned 47.

It was the same age that her father died, in 1996.

Theresa MacPhail: He wasn't that old. He was only 47, and we lived in New Hampshire. Granite Stater for life, yo.

Nate Hegyi: This is Theresa. And, I gotta hand it to her, despite the topic… she’s a lot of fun to talk to.

Anyway. Her dad – James – was driving in a sedan down Main Street in a small New Hampshire town.

It was summer. James was with his long time girlfriend, listening to the Red Sox, cigarette in his hand dangling out the window.

And he rolled up to a stop sign. And then…

Theresa MacPhail: a bee was just on its normal pollen collecting route, flew straight in the window and landed on my father's neck.

Nate Hegyi: And stung him.

Now, James had been stung by a bee a few weeks earlier… But he took some Benadryl and he was fine.

This time in the car though, Things got bad, fast.

Theresa MacPhail: His neck started to swell, which obviously affected his breathing.

Nate Hegyi: He pulled over and asked his girlfriend to drive. And they went to the closest pharmacy.

By the time they pulled up, James was gasping for air. But the pharmacist… refused to give him epinephrine, a shot that could save his life.

[MUX IN: Heather, Blue Dot Sessions]

Theresa MacPhail: at the time there were laws. Pharmacists were not legally allowed to give anyone a shot.

Nate Hegyi: So they couldn't inject him.

Theresa MacPhail: No. They had to call the paramedics.

Nate Hegyi: The paramedics arrived, but they didn’t have epinephrine. It wasn’t as common back then for ambulances to carry it. Instead, they intubated him and rushed him to the hospital.

Theresa MacPhail: And they did chest compressions when his heart eventually went into arrest.

But it wasn't enough. And by the time he got to the hospital, he was already dead on arrival

[MUX SWELL AND OUT]

Nate Hegyi: This is a tragic and scary story, especially for anyone who has, or KNOWS someone who has a serious allergy.

But it’s also a story that leaves me with a lot of questions about how allergies work… and why we even have them.

I mean, I’m allergic to peanuts, have ALMOST been hospitalized a couple of times… and even I don’t know.

Lucky for us, Theresa is now the author of Allergic: Our Irritated Bodies in a Changing World… and she is full of answers.

Theresa MacPhail: So what’s happened, say, if you are allergic to peanuts, is that at some point in the past, you ate a peanut. The peanut protein came into contact with a T cell that decided it did not like the looks of the protein structure.

[MUX IN: Mai Tai (Instrumental Version), Epidemic Sound]

Nate Hegyi: Okay, let’s take a human biology 101 detour.

A T cell is a type of white blood cell. They’re like, the manager of a club.

Theresa MacPhail: So it took a little chemical snapshot, a protein snapshot.

Nate Hegyi: Kind of like a “blacklist. If you see these guys get em out”

Theresa MacPhail: and delivered it to B cells. And what they do is they produce antibodies.

Nate Hegyi: So the B cells get the blacklist, and when they recognize someone on it… they call security: antibodies. Antibodies are trained to recognize, just one thing – whether that’s the coronavirus, or tetanus bacteria, or flu.

But sometimes antibodies get trained to recognize something that’s harmless: say, a peanut protein.

The peanut protein just wants to get into the club. But things escalate, security overreacts, and they bust out the pepper spray.

Theresa MacPhail: It’s going to recognize the peanut protein, and it's going to attach itself to a mast cell. And what mast cells do is produce histamine.

Nate Hegyi: Histamine causes all sorts of reactions like sneezing, itching, or vomiting to try to get rid of the allergen.

But… why? Why are some people’s immune systems going on the fritz? Targeting something as innocent as a peanut protein. You can eat peanuts, I can’t. It’s not fair.

[MUX OUT]

One idea is the parasite hypothesis.

The parasite hypothesis starts with the fact that there’s one type of antibody that’s involved in the vast majority of allergens. It’s an antibody called IgE.

And you know what else IgE defends against? Parasitic worms.

Theresa MacPhail: So the theory is that at a certain point when we had a lot of intestinal worms, or we were coming into contact with a lot of parasitic organisms, that Ige would have actually been protective.

Nate Hegyi: But with the decline of parasitic infections in developed countries …

Theresa MacPhail: they have lost the thing that they were designed to protect against. And so they are finding something to do.

Nate Hegyi: And the thing they’ve latched onto instead of fighting worms, is to fight peanuts and shellfish and eggs.

Theresa MacPhail: For those of you who have kids, I like to use the analogy that your Ige is sort of like you left your three year old in a room with crayons unsupervised. Okay, it's going to find something to do.

Nate Hegyi: Yeah, uh huh, uh huh. It’s gonna find something to do, because it’s bored.

Theresa MacPhail: You’re not gonna like it either.

Nate Hegyi: There are other ideas out there too. Another one is the toxin hypothesis… which basically says that allergies might be connected to venomous bugs and animals.

Theresa MacPhail: something about this process, maybe even the slowing down of the blood rate, would have allowed our ancestors to cope with a small snakebite.

Nate Hegyi: But the truth is… No one really knows for sure. Why we get allergies is still a bit of a mystery.

What we DO know is that when your immune system is reacting to something you’re really allergic to it’s a snowball effect where the immune system just KEEPS making histamine. And THAT’S when things can get dangerous…

[MUX IN: County Seat, Blue Dot Sessions]

Theresa MacPhail: that rolling histamine ball will lead to shock where your body just can't cope with all of the things that are happening because of your immune response.

Nate Hegyi: In other words, anaphylaxis.

Histamine constricts muscles in the lungs presumably to protect you from irritants and airborne toxins. But, too much, and you can’t breathe.

Histamine also dilates blood vessels so that more white blood cells can go join the fight. But dilate too much and you can go into cardiac arrest.

Theresa MacPhail: So for most of us, if we get an injection of epinephrine within the first 15 minutes of a reaction, we're probably going to make it to the ER. We're probably going to make tallit through the event. It's going to be scary for everybody involved, but you're going to be okay.

[MUX BEAT]

But unfortunately, all of this is so fast that it only takes 30 minutes to to unfortunately succumb.

Like my father died of a bee sting

and he was dead within 30 minutes of the sting.

So it's quite fast, and it's really important to get people the adrenaline and to get them into a health care facility as fast as possible.

Nate Hegyi: Because of the increasing number of people with deadly allergies, ambulances are more likely today to have epinephrine on hand.

[01:13:22-01:13:32] Theresa MacPhail: So it's just a tragedy that my dad was I mean he was always a trendsetter you guys in all the worst ways possible.

[MUX OUT]

Nate Hegyi: Ok. Random allergy storytime. This is Dwayne Smith.

Dwayne Smith: One day I’m talking to my mother. And I go, I can’t get rid of this rash. I keep breaking out. It keeps getting worse. The doctor gave me this cream it seems to be working, but it’s not the greatest. I have to figure out what’s causing this.

She goes, it’s probably from eating all those eggs!

I go, what does that have to do with anything?

She goes, you know you’re allergic to eggs.

I’m like, No I didn’t. I did not know that I was allergic to eggs.

She goes well you never ate eggs.

I said yeah, because I didn’t like them. I thought they were making me vomit.

She’s goes yeah you were vomiting because you’re allergic.

I stopped eating eggs, and my rash cleared up within three days.

[MUX IN]

Nate Hegyi: So, are allergies getting worse? And if so, why? I mean, c’mon - isn't’ there enough going on already?

That’s after the break.

[MUX SWELL AND OUT]

<<MIDROLL>>

Nate Hegyi: Welcome back to Outside/In. I’m Nate Hegyi. And the next big question we want to answer is: are allergies getting worse?

The answer is most definitely, yes.

Theresa MacPhail: So our lifestyles and our environments have changed dramatically over the last 200 years, and it's kind of left our immune cells playing catch up.

This again is Theresa MacPhail, author of Allergic: Our Irritated Bodies in a Changing World.

Theresa MacPhail: And I often like to say like, just imagine you're trying to use your computer to do a zoom call, but you're running windows 97.

It’s not gonna go well.

Nate Hegyi: Allergies have been documented in historical records at least as far back as 2,400 years ago, when Hippocrates wrote about “hostile humors”... and how some people suffered symptoms after eating cheese.

(...though… that does sound a little like lactose intolerance, which is a whole ‘nother thing.)

Regardless… many of the widespread modern day allergies of today? These are relatively new.

Theresa MacPhail: so what has happened in the last 200 years that we've seen the arrival of things like hay fever, which we don't really have a lot of evidence for prior to the 1800s or the 1800s. And we don't really have a lot of evidence for food allergy before that same time period, like last century or so.

Nate Hegyi: Some of that might have to do with evolution and genetics, like we talked about with the parasite and the toxin hypotheses before the break.

But it might also have to do with how our lifestyles have changed.

And one big thing that’s changed in Western society is everything is a lot cleaner now.

[MUX IN: Dolly Pop, Blue Dot Sessions]

In 1989, a scientist noticed that in big families, younger siblings had lower rates of hay fever and eczema. His hypothesis was that they were being exposed to more germs at a younger age because they had older siblings tracking them back into the household.

And then scientists found another group of kids with lower rates of allergies: kids who grew up on farms with livestock.

What this seems to point to is that more germs… equals fewer allergies. And so those of us who live in a more sterilized world wind up with more allergies.

But Theresa says this doesn’t tell the whole story. Just because you move to the city doesn’t mean you’re not dealing with germs. I mean, it’s not like the New York City subway is sterile, for example.

And later research showed that 20-30 percent of farmers in America DO go on to develop allergies, mostly to things like mold and organic dust.

There are other signs that our modern, industrialized ways of living might be part of the problem though.

For example:

Theresa MacPhail: something called the old friends hypothesis.

Nate Hegyi: The old friends hypothesis.

Theresa MacPhail: So the old friends hypothesis is that we have altered our gut and skin microbiomes, and we no longer have the same commensal bacteria, just a fancy way of saying friendly bacteria.

Nate Hegyi: Antibiotics are a very new thing in the grand arc of humanity. The same goes for processed foods.

One study showed that kids who’ve taken antibiotics before age 2, are more likely to have allergies than their germier classmates.

These hypotheses help explain why… for a long time… allergies were only happening in industrialized countries. Now, we’re seeing the same patterns take hold in new places.

Theresa MacPhail: So when countries start developing allergic disease, it's it's because they are industrializing and they are getting wealthier.

And it always happens the same order. You get hay fever and asthma spiking through the roof, then that stabilizes. And then you get eczema and food allergies spiking through the roof.

So if you look at a country like India and even China right now, they have gone through their asthma spikes. But they are just entering their food allergy period.

[mux out]

Nate Hegyi: But there is another big reason allergies are getting worse… and that’s climate change.

Just like humans… the plants that give us allergies are trying to adjust to shifting temperatures, pollution, extreme weather.

And one consequence of that is…

Theresa MacPhail: pollen levels are supposed to double by 2040. So if you are walking outside this spring and you are looking at your car and you're thinking, there seems to be more yellow dust this year than ever before, you are right.

Nate Hegyi: But it’s not just that there’s more pollen… it’s also more potent.

That’s because changing the chemistry of our air changes the chemistry of the living things that breathe it.

Theresa MacPhail: And then the other weird thing is that we increasing CO2 levels are really great for plants like poison ivy and ragweed.

Nate Hegyi: And then in some places, winters are getting shorter, which means

Theresa MacPhail: longer growing seasons.

…and longer exposure to pollen.

But wait, there’s more!

Theresa MacPhail: more flooding leads to more mold. So you're going to have more mold allergies.

Add to that more air pollution from wildfires… and you’ve got the perfect storm: genetics, changing lifestyles, and a changing planet.

[MUX IN?]

Theresa MacPhail: the way we know things are actually getting worse, is you can look at things like EpiPen prescriptions. So those have increased four times four fold over the last 20 years. So you can look at that. You can also look at ER admissions. So you can look at the percentage of people showing up to the ER with asthma and food anaphylactic events and those have increased.

Nate Hegyi: It’s not just us, by the way. Even our pets are getting more allergies. Cats get asthma. Dogs, get itchy skin. Pet birds get them. Domesticated horses get them.

Theresa MacPhail: So anything that live in close proximity to us.

And I have a lot of people say, well, do deer get it or do raccoons get it? And first of all, we're not looking. There's not many studies on whether or not raccoons are sneezing out by your trash can, but we don't think so.

[MUX SWELL AND OUT]

Nate Hegyi: Random story #2: from Lily Ko (KOH rhymes with “go”).

Lily Ko: I had a cookie at a work party that had walnuts in it. I could tell from the first bite or two that it was a tree nut cookie, and I should have stopped eating it.

But I thought, I really want to eat this cookie so I stuffed it in my mouth…sometimes I think, oh if I eat it really fast, you know, the reaction would be over with sooner.

That’s a ridiculous assumption to have.

[MUX SWELL]

Nate Hegyi: So, what can we do about our allergies? Are we just stuck carrying around EpiPens and antihistamines like Benadryl the rest of our lives?

If you’re lucky, you might actually grow out of your allergies. That can happen: as your body changes, so does your immune system.

[MUX OUT]

Puberty, pregnancies… big biological milestones can change how we react to everything from peanuts to pollen.

But even there, the story is a little depressing.

Theresa MacPhail: we're seeing less children grow out of them. So it used to be quite normal. You would have like say a corn allergy or a milk allergy when you were younger. And then at 24 your body is like, okay, we're done with this. We get it. Now, more and more people are going into adulthood with those same allergies.

Nate Hegyi: This brings me to one particular question that keeps coming up…what about bee pollen and local honey? Some people say that eating it protects you from hayfever.

Is this like Instagrams secret that’s going to help us get through all these changes?

Theresa MacPhail: I know I'm going to disappoint a lot of people, but absolutely not.

If it was going to work, you'd have to shove it up your nose.

It goes back to how you’re introducing the thing. the theory is that it's like immunotherapy. You're exposing yourself to those pollens, but you're exposing your stomach cells to those pollens, not your nose.

So by all means, if you want to do a self-experiment and shove a little honey in your nose and see if that works. But I don't think many of us are willing to do such an experiment.

Nate Hegyi: So the bee pollen and local honey trend may be all over Instagram… but proper immunotherapy has been around for a while.

Back in 1911, a scientist injected people with grass pollen extract to try and alleviate their hay fever, and it actually worked.

The idea is to introduce a very small, trace amount of an allergen to your body. To basically retrain your immune cells to be okay with the allergen.

Or, as Theresa puts it…

Theresa MacPhail: You're trying to make a better impression.

They first they got the wrong impression. Yeah. We're trying to change it. Yeah. By small introductions like see peanut isn't that bad.

Nate Hegyi: Yeah. Right. We like peanut don't we.

Theresa MacPhail: We like peanut.

Nate Hegyi: Immunotherapy works for about 80% of people who try it.

But it can be an uncomfortable process. Even in trace amounts, the allergen can still cause hives, it can upset your stomach. And, it’s very rare, but it can cause anaphylaxis. Which is why you want to do this properly in a doctor’s office.

[MUX IN]

Nate Hegyi: So these three episodes, we’ve been talking about things that can kill you. But what we’ve learned is that, in each case, there’s a weird relationship between health and sickness.

The dose makes the poison. Inside the venom… is the cure.

With allergies, all the ways that we are changing our relationship to the outside, are changing the insides of our bodies in ways we don’t completely understand.

I am struck by how weird it is that something as simple as a PB & J that thousands of children are eating right now… would send me to the hospital.

To be clear - I’m not saying I’d give up antibiotics, or infect myself with parasitic worms, in order to not have a peanut allergy. I’m just saying that everything is connected.

[MUX SWELL]

And that brings me back to the story of James MacPhail. Theresa’s dad.

Theresa MacPhail: A bee sting killed my father, but that’s not the only thing that killed him.

Nate Hegyi: This is Theresa, reading from the epilogue of her book.

Theresa MacPhail: If he hadn’t been a smoker, he wouldn’t have had his window open that day, and the bee wouldn’t have flown in.

He didn’t carry an EpiPen because it was too expensive.

He was a smoker because he was stressed out, trying to make ends meet.

He was trying to make ends meet because he didn’t have a college education, because he enlisted in the army at eighteen instead.

And his reasons for doing that are his own.

I began this journey because I wanted to diagnose the problem of allergy in America. But at the end, I think what I’ve started to glimpse is really the story of what is happening to all of us—to humanity itself—as we grapple with how we’ve altered our environment and continue to reshape the worlds around us.

For better or for worse, allergies prove that we’re all in this increasingly irritated world together.

And it will take all of us working together to effectively treat our condition.

[MUX TRANSITION]

Nate Hegyi: That’s it for our episode today about allergies. If you’ve got an allergy story to share with us, tell us about it. Record yourself on a voice memo and email us at outsidein@nhpr.org.

Or hit us up on social media. We’re @ Outside In Radio on Instagram, Tik Tok, and X.

And that wraps up our series on things that can kill you, from poisons, to venoms, and now allergies.

By the way, we hope we haven’t unlocked a new level of anxiety for everyone. Theresa just wants to reassure our listeners.

Theresa MacPhail: in case you're panicking and this is going to give you a phobia for bees. Only 65 Americans die from this every year. It's incredibly rare to die from this.

Nate Hegyi: Anyway, let us know what you thought about this little triptych. And tell us what you’re curious for us to dig into next. Let us know.

Again, you can email us at outsidein@nhpr.org. Or give us a call at 1-844-GO-OTTER.

<<CREDITS>>

Nate Hegyi: This episode was reported, produced, and mixed by Felix “T Cell” Poon.

It was edited by Executive producer Taylor “B Cell” Quimby.

I’m your host Nate “Mast Cell” Hegyi.

Rebecca Lavoie is director of on-demand “audio immunity” at NHPR.

Our team also includes Justine Paradis, Marina Henke and Kate Dario.

Special thanks to Dr. Trisha Ray, and Dr. Ruslan (ROOS-lawn) Medzhitov (MEH-jih-taw-v) for talking to us about allergies.

And a very special thanks to everyone we talked to about their allergies: Kelly Mahoney, Dan Tuohy, Michelle Liu, Mara Hoplamazian, Jackie Harris, Rick Ganley, Jason Moon, Emily Quirk, Beni Osei Duker (BEH-nee OH-say DOO-ker) on passing out at a Wegmans parking lot, Dwayne Smith on his egg allergy,, and Lily Ko (KOH) stuffing her face with cookies. Thanks also to Kezia Chee, Greg Hum, and Hang Le (HANG LEE).

Nate Hegyi: Music in this episode is from Blue Dot Sessions, Particle House, and Caro Luna

Our theme music is by Breakmaster Cylinder.

Outside/In is a production of NHPR.