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Guess what Will, What's that Mango?
I was looking through the Ignoble Prizes, which released this week, and for those who don't know, these are funny prizes that honor academic papers that are so surprising that they make people laugh and then think. And one of the articles that caught my attention was a Piece Prize that they gave out for studying the pleasure ability of scratching an itch.
I do love that they gave out a peace prize for this, but like, what did the scientists actually find in this study?
So apparently they were looking into when you itch, what areas that you can scratch are most satisfying. So they looked at a few areas and triggered scratching in people in those places, and they came to the conclusion that the places where a little scratching is most satisfying is on your back.
Mm hmm. I could have guessed that a backscratch obviously feels amazing, But the other place.
Of high pleasure your ability was the ankle. If you got a mosquito bite, for instance, on your ankle scratching it results in the most satisfaction, and apparently the higher the scratch on your foot, like the closer it is to the ankle, the more satisfying it is.
You know, I think if you had asked me, like where the most pleasurable place to scratch an itch was, the ankle might have been tenth on my list. But now that you're saying it, and especially when you say mosquito bite, I actually sort of get it. It makes sense.
Yeah, well, I'm so lucky it enough to quiz you on all the.
Other places that you I can name the others, actually I'll put to I'll email you a list.
But all this reading about itching and scratching made you want to look into the science of itches, like why do we itch? Why does it feel so good to scratch? And what's our body trying to tell us from all of this? So let's dive in.
Hey, their podcast listeners, welcome to Part Time Genius. I'm Will Pearson and as always I'm joined by my good pal Mangash hoot Ticketer and sitting behind that big booth, and he's always up to something interesting. This week, he's got a whole bunch of posters behind him, and actually these appear to be homemade but very professional posters behind him, one of them of Itchy and Scratchy from The Simpsons, one of them the character poison Ivy from Batman. Sorry,
that one took me a minute. And then I think that's a poster of the musician Lee scratch Perry. Is that the right? Okay? All right, all because we are doing an episode on itching. So well done, Dylan. That's our wonderful producer, Dylan Fagin.
Actually, you know, before we start talking about this, I love that he's got that Itchy and Scratchy poster up there. And I read this thing about how sometimes the Simpson writers used to use the Itchy and Scratchy cart tune just for inside jokes. And there's this one episode where the writers added a character called Puuci to the mix, so it was like Itchy and Scratchy and Poucy because apparently a focus group had recommended that they add another character,
and the whole show ends up being a disaster. But what I didn't realize was that it was basically making fun of the fact that I think this was in the eighth season, the execs at Fox asked the Simpsons writers to add a teenager to the family because they thought it would I guess make the show more lively or something. And the Simpsons writers refused, but they decided to mock it on the show in Itchy and Scratchy, which I just think it.
So fun.
Anyway, I had to throw that tangent in there. But let's get started, all right.
Well, one of the things that I wanted to look into is why we say we're itching to do something, like when we're eager to do something, and it actually comes back to Latin so weirdly, on our skin, we have these special itch sensing nerve endings and when they get stimulated, this is whether it's by mechanical, thermal, or chemical mediators, we get an itching sensation. So those nerve endings are called pre receptors. And in fact, the scientific word for itching is proitis.
I actually love when the scientific words for things are so different, Like apparently the scientific word for burping is eructation. Is it?
Really? I did not know that?
So tell me a little bit about proritis.
All right. Well, Proitis comes from the Latin word periray, which means to itch or to long for it's hard to say, but that's what it means.
So the idea of longing and desire is linked with this physical sensation of itching.
Yeah, that's exactly right. And you know it makes sense because when you have an itch, you feel like you have to scratch it. Actually, the first recorded definition of an itch came from a German physician named Samuel Hoffenreffer back in sixteen sixty. So he defined an itch as quote, any unpleasant sensation that elicits the desire or reflex to scratch or put another the way, if you're scratching something, then the sensation that provoked it is, by definition an itch.
Can you talk about that itch pain relationship a little more?
Mm hmm. There's a complex relationship between itching and pain. The pure receptors I mentioned before are on the end of specialized nerve cells called sea fibers, and these sea fibers are identical to those associated with the sensation of pain, but they are functionally different because they only convey the
itch sensation. So when they're stimulated on the skin, these sea fibers carry signals along the nerve to the spinal cord and onto the brain of course, and that's where they're processed, and that generates this scratching or rubbing reflex response to that itch.
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Well, scratching it interferes with the sensations arising from these pre receptors. And this is the interesting part. They do this by stimulating various pain receptors in the same areas, so the pain is almost like a save for the itching. And you know, it's not just scratching that will stop an itch, like other painful stuff like heed or capsation. Of course, the hot stuff and pepper's or even electrical
shocks can stop itching. I don't know that you'd want to take it to that link, but it turns out that does work. But you know, pain can stop an itch. But it's unclear whether the pain and itching are separate sensations or like the same sensation.
But I don't know, just less, can you talk about that relationship a little more?
There's basically two theories about how this works. So there's the intensity theory and the specificity theory. So the intensity theory states that the skin is studded with this array of nerve endings called no susceptors. Now, their job is to relay information about the presence of potentially damaging stimuli to the spinal cord and the brain. And so a weak assault on these neurons result in an itch, while a fully fledged attack results in pain.
So, like you said, the same sensation but less.
I nailed it, and I'm glad you understand it now. But you know, the specificity theory states that some neurons are responsible for pain while a different set cares about an itch. Or alternatively, it could be that there's a single set of neurons responsible for no susception, but that they somehow tell the difference between sta simuli that are itchy and those that hurt.
But you would never scratch something that's just hurting you, right, Like you don't stub your toe and then scratch at it to stop the pain.
Right, I mean, there are distinct sensations that elicit these very distinct reactions. So when something hurts, our body responds, you know, with their withdrawal reflex. But you know, think about it. You put your hand over a fire, the pain makes you yank get back, But the scratching reflex brings attention toward rather than away from the affected skin.
And you know this is probably evolutionary. Like if you're looking closer at a quick scratch, or even just mindlessly scratching at something, it's pretty effective at removing an insect or other unwanted material from your skin or your hair. So it actually works.
Yeah, that's interesting about a scratch drawing attention to your skin or your body.
Yeah, And so here's how it works. Like when something bothers the skin, like a mosquito bite, the cells release a chemical, usually a histamine, as an immune response to this, and that release provokes the no susceptors in the skin to send a message to the spine, which then relays the message through a bundle of nerves called the spinathalmic
tract all the way up to the brain. So, in two thousand and nine, this group of researchers used the histamine injection to make the legs of their non human primates itch while an electrode monitored what happened inside those tracks. And as soon as the histamine was injected, the neurons started firing faster. So when the researchers offered up a
few scratches, those neurons slowed their fire. And what those electrodes showed them was that the scratching actually does its work in the spinal cord rather than the brain.
So I'm actually glad that you brought up that spine itch connection because I saw something about that in my research and decided to look into it a little more. But before we get into that, let's take a quick break.
Welcome back to Part Time Genius. We we're talking all things itchy. So, Mango, you were just about to talk about the connection between the spine and itches.
Yeah, So this discovery comes from two thousand and seven, when a professor and researcher named Jufeng Chen at the Washington University School of Medicine led a team that was looking into the role of a specific receptor called GRPR. It's the gastrin releasing peptide receptor, and he was trying
to figure out what it had to do with itching. Now, no one had really studied itch as separate from pain before two thousand and seven, but Chen and his team were looking at mice that were missing the GRPR gene to see if they reacted differently to pain stimuli than normal mice did. And while they didn't react any differently to pain, when they stimulated the GRPR in normal mice, the mice started scratching themselves as if they had this
really bad itch. And that's how they figured out that the pain sensation and the itch sensation are mediated by separate sets of genes in the spine, which means potentially that drugs can actually be used to suppress the itch sensation without affecting the pain sensation. And that's particularly important because pain can be kind of this like protective queue that warns of danger.
So it'd be great to.
Have this anti itch medication that doesn't compromise our pain sense and capability.
Yeah, I mean that makes sense. It's best to be less itchy and safe ideally.
Yeah. But Chen didn't stop there, so ten years later, in twenty seventeen, his teammate another really interesting discovery about itchiness.
I keep itching just talking about itching. It's almost like when you're in a place and you're not supposed to laugh, and then you can't help. But laugh that that is the experience I'm having.
I don't know about Youah yeah, totally. I want to scratch my head so badly, right yeah. And it's funny because you know, his team actually was the ones that discovered that itchiness is contagious. So they did this experiment with two different groups of mice. And I'm not sure why it's always mice. It's never like a group of
frat guys who lives in Williamsburg. But the researchers bred one group of mice to be chronically itchy, and then they put the itchy mice in a cage next to normal mice, and then they recorded hours and hours of both sets of mice. And when they analyzed the footage, they discovered that the normal mice, just by observing the chronically itchy mice scratching, scratched themselves twice as much. Basically, the normal mice became twice as itchy.
Imagine what fund we could have making other people scratch themselves, Mango, Like, all we have to do is stand around them for hours scratching ourselves.
It sounds like a really good use of time, but it turns out there are other ways to get people to itch too. So in nineteen ninety nine, German researchers found that just listening to a lecture about itching made the audience itch and start to scratch themselves. And the aim of the lecturers was to present an itch inducing lectures. So they showed all these slides that induce scratching, right,
like pictures of fleas mites, allergic reactions. Then they showed slides that induced relaxation and a sense of well be So they showed like pictures of baby skin and soft down and a mother with a child in her arms, and they discovered a few fascinating things. So first the self reported itch sensation and all this observed scratching increased after they showed those first set of pictures. But after hearing the lectures discussed the next set of things and
showing those other pictures, the observed scratching decreased. So you can actually lower the itch sensation when you show calm soothing pictures.
I've never really thought about it, like working in reverse, So you could potentially soothe an itch by looking at calming images.
Yeah, but I guess the question is like, would you want to do that?
What do you mean?
So? I mean itch remedies are great, but sometimes itching is medically necessary, right, and sometimes isn't the best feeling of the world, like a really good backscratch. I mean, people have been talking about this forever. In a nineteen forty eight paper in the Journal of Investigative Dermatology, this neurophysiology, just George Bishop wrote, quote, scratching an itch with a violence that would cause pain elsewhere maybe experienced as one
of the most exquisite pleasures. And the poet Ogden Nash once said, quote, happiness is having a scratch for every itch.
I mean, that's definitely true. But you know, like the pleasure and pain cocktail of an itch is, it's pretty complicated. Like patients with exema have reported that they scratch not until the itch has subsided, but until it no longer feels good to scratch, So it's a little different.
Yeah, that makes sense, although it seems like you know that that could exacerbate the skin conditions, right.
Yeah, not only that, but chronic itching can cause psychological distress. And this is something we really don't think about that much. But there's a stigma associated with skin disorders and scratching. So one study interviewed adults with chronic itching conditions, and almost all of them said that itching had profound emotional effects, such as depression or guilt or panic and you know, sometimes feeling isolated because the resulting scratching elicited such negative
responses from other people. And it might even have historical roots, like in early European medical practices, and itch wasn't just equated with an affectious disease. It also conveyed these moral lapses, like like a lack of hygiene or social inferiority. So there was a lot wrapped up in it.
Yeah, that makes a lot of sense about the social history that you know. This just reminded me of a story when Henry was like three years old. We had this couple over to our house for dinner and we were all sitting downstairs and we put Henry to bed, or we thought we'd put Henry to bed, and then like he walks down completely naked. He's like two years old, and he goes, guys, I got examunt. Oh no, I don't even know how we learned the word examon and where his clothes work.
But it was Yeah, so like weirdly, that sort of thing is not socially acceptable to just walk into a room naked and announce that. So it's just I see what we're talking about here, But I mean, you know it. You think think back to when humans learn to associate certain things with disease, like around scratching or as we're talking about here, that can actually trigger a physical disgust response, which is unfortunate, but that is what happens.
Yeah, it seems like something everyone should be able to empathize with because wind to scratch an itch is universal. But obviously there's acceptable scratching and unacceptable scratching.
Right right, And then there's this itches that don't respond like even to excessive scratching, meaning you could scratch and scratch and never actually get at these itches.
Yeah, which sounds like torture.
No, I really does. And there's actually something called a neuropathic or neurological itch, which is a type of itch under the skin that you actually can't scratch to relieve because it's caused by nerve damage rather than issues related to the skin, and it can be caused by things
like diabetes or shingles, brain lesions, or liver diseases. There's you know a host of other things that can lead to this, and you know, the itch tends to be chronic, difficult to treat, and there's really not much you can do about it.
Yeah, I remember there was like a New Yorker piece about a woman who had an itch on her skull and she just couldn't stop scratching at it, and it just like led to all sorts of issues, which just sounds miserable, But you know, there are also things that are kind of the opposite of that. In the nineteen fifties, there was this scientist named J. R. Traver who suffered
from a condition called delusional parasitosis. It's this condition where people have become convinced that they're infested with parasites, which leads to itching, and Travor refused to accept that this was just a delusion, so she published a paper about her experience combating what she called skin mites. She visited tons of doctors, used dangerous pesticides on herself, tried to scratch the phantom mites out with fingernails, and it went
on for her whole life. Travers actually started to itch around her fortieth birthday and continued scratching at these delusional itches until she died forty years later. Now, Unfortunately, since then, other people with delusional parasitosis have pointed to Traver's work evidence that in fact they do have an itchy parasitic infection and not a psychiatric condition, which it actually is.
Well, I mean that also just sounds like torture.
Yeah, imagine thinking your body was covered in mites for forty years. It would be like constant scabies, right.
Yeah, I actually speaking of that you were talking about you looked into scabies, right, like, can can you actually explain it a little force? I feel like it's one of those words that's used without people actually understanding it.
Yeah, and weirdly, I've heard of people getting it recently. But scabies is a skin condition that causes almost this like unbearable itchness, and it's caused by tiny mites that
do burrow into your skin. Like. The mites have been around forever, but it wasn't until the eighteen thirties eighteen thirty four at the Hospital Saint Louis in Paris, that the mites were discovered as the cause of scabies, and at the time about sixty five percent of the beds in the hospital were occupied by patients suffering from scabies.
It was a Corsican student named s Fernucci who had been taught by peasant women of his home island how to extract the mites with a pin, and he showed the method to the doctors at the hospital.
So people actually had to be hospitalized for scabies.
Yeah, it can be really debilitating, and scabies was also a big problem during the American Revolution. This was before they discovered the cause with skin mites. They called it the itch. And in fact, it happens at Valley Forge when George Washington is there and he issues this general order that proclaims, quote being also informed, many men are
rendered unfit for duty by the itch. The commander in chief orders and directs the regimental surgeons to look attentively into this matter, and as soon as the men who are affected with this disorder are properly disposed in huts, to have them anoided for it. I mean, it's pretty crazy.
It's amazing that the itch was enough of a concern in the middle of a very bloody war, Like it just speaks to how bad these afflictions are. And so I think one of the central questions of life mango and here is to scratch or not to scratch?
Yeah, one of Hamlet's lesser known soliquy.
Yeah, it was a really powerful one. So we all have this reflex to scratch an itch. But it's a big question, like to scratching help or hurt us? And it's a question scientists are actually looking into this study as recently as twenty twenty three. It was at Harvard Medical School, and it showed for the first time that a common skin bacterium Staphylococcus eras or s RAS, can cause an itch by acting directly on nerve cells. So this helps explain why common skin conditions like exima and
atopic dermatitis are often accompanied by persistent itch. So in these conditions, the equilibrium of micro organisms that keep our skin healthy is often thrown off balance, so it allows this bacteria to flourish and so it can cause an itch by instigating a molecular chain reaction that culminates in the urge to scratch.
But why would a microbe like cause us to itch? Evolutionary speaking, like what's in it for the bacterium?
It's a good question. I mean, researchers say that the pathogens may be hijacking the itch sensation and other neural reflexes to their advantage. So, for example, previous research has shown that the TB Bacterium directly activates vagual neurons to cause cough, which might enable it to spread more easily
from one host to another. There's another researcher that speculates that quote the itch scratch cycle could benefit the microbes and enable their spread to distant body sites and to uninfected host That's interesting.
I feel like you always hear people say don't scratch, it'll make it worse, But what it actually means is like you'll make a better home for the bacteria. But you know, sometimes scratching an itch is just a really harmless, joyful pastime.
I mean, I'm guessing you're going somewhere with this, So what do you mean exactly by that?
So have you ever heard of ruyi?
I don't think so.
It's basically a very fancy backscratcher. Really was a ceremonial scepter used by Chinese nobles and monks, and it's revered by Chinese people for its symbol of good fortune and longevity. But originally it was just designed as a backscratching instrument.
So wait, so noblemen would take this scepter, this important symbol of good fortune, and just start scratching themselves with it. That just seems pretty casual.
Yeah, so not exactly. The ruiz popularity peaked during the King dynasty, and it was first used by the common folk before Chinese emperors and imperial officers took a fancy to it, and then to suit the imperial taste and exquisite rui was manufactured by the nation's top craftsmen. But over time the ruie stopped being used as a backscratcher, and just because of its beautiful craftsmanship, it rose in status as almost this preferred choice of imperial gifts.
So the ruery jumped classes from like practical tool for their commoners to this symbol of grand Europe.
Yeah. But one other cool thing is that in Chinese means quote everything goes well. And I feel like that's the best way to articulate the feeling you get when you're like scratching in it.
Yeah, when you're locked in on a good scratch, it really is a beautiful moment. Like we should focus on that for just a second, Like everything goes well when that happens.
So the first time I wanted to scratch because it feels good, not just because I'm feeling itchy, but right exactly, I feel like I've got to get you a rui. But before I do that, why don't we do a quick fact though, So here's one to get us started. In twenty sixteen, neurologists from Germany's University of Lubec discovered that you can soothe an itch by tricking your brain
with a mirror. So if you look into a mirror while itching and scratch the opposite side, the itch will subside as if you're actually scratching at the point of the itch. And apparently the trick can be used to help people who have severe skin problems to stop them from further hurting areas where their skin is healing.
Are well, here's a question that a lot of cat owners want answered. Why do cats love clawing at your furniture? And I guess the question I would ask is why do you have a cat? But either way, it turns out there, yeah, there's so many questions here, but it turns out there are more than a few reasons. So one is the scrape off the nail tip so that
they can grow fresh sharper nails. And another is that apparently all that scratching works like a massage, so after sleeping for sixteen hours a day, all that pawing and clawing helps them work out the kinks and their back muscles actually, but the main reason, according to cat scientists, is it's territorial. So the scratching leaves marks to let other cats and humans know who really owns the sofa, as well as a personal scent that comes off, you know, from their papads.
I mean, the territorial stuff makes sense, But like I never thought of like scratching as like recovery for cats who are sleeping a lot.
Yeah, I totally didn't think about that either.
So did you know that certain fruits and vegetables can make your mouth itch? And this is according to New York mags the cut. It's related to allergies, So if you're allergic to tree pollen, there's a good chance that carrots and kiwis will be a problem. If you're allergic to summer grasses, tomato and watermelon can make your mouth itchy, And if you have trouble with autumn weeds, apples and bananas have proteins that trigger those same allergies.
Yeah, I hadn't thought about it, but I feel like I actually get that from certain certain foods, like pineapple. After I ate it, sometimes I just feel like something has like cut up my tongue.
Do you know what I'm talking about?
Yeah, I don't know if that's the same thing, But I think I'm just trying to say I relate to it. I'm just trying to relate to what you're saying, mango. But all right, well I got another one. So in the run up to the Olympics, the French released a
scratch and sniff stamp featuring the baguett. The wonderfully Aromatic stamp was released on the feast day of Saint Honore, the patron saint of Baker's, along with an official statement from the Post Office that proclaimed, quote, the baguette, the bread of our daily lives, is the symbol of our our guesstronomy and the jewel of our culture. But as The New York Times joked, there is no word on if a croissant stamp will follow.
I feel like, just like smelling fresh bread from a sticker would make me want to buy like a loaf of fresh.
Bread, like totally good marketing.
So here's something I learned from our old palasin mental flaws. The phrase from scratch, like baking something from scratch, weirdly comes from sports. So the idea of starting from scratch came from a scratch line that was scratched into the ground as the starting line for a race, and it kind of evolved to starting at the very beginning and eventually starting without help. So when you bake something from scratch, you're starting from the origin.
That makes sense, all right. Well, here is a really crazy one about a man named Bill Morgan from Melbourne, Australia. In nineteen ninety nine, Bill had a heart attack and fell into a coma for about two weeks. He was just thirty seven years old, but somehow he miraculously woke up from it and to celebrate his survival, he went out and bought a scratch lottery card and I guess in Australia you can win other prizes, but he won
a car worth about twenty seven thousand dollars. Anyway, when the local news heard about the incident, the story of him coming back to life and winning the lottery, they asked him to recreate this for a news segment, so they filmed him going into a shop buying a ticket and scratching the foil, and when he did, he won again. This time he won a two hundred and fifty thousand dollars jackpot. Is that not nuts?
That is nuts? It's almost like worth the coma.
Ye, exactly, there's a short list of things that are worth the coma. But yeah, you're probably right on this one.
I actually had a fact about scratch lottery tickets too. It's about these two artists who make sculptures from discarded scratch off tickets to represent discarded dreams. So they used like forty thousand dollars of discarded tickets to make a dream car sculpture, and they use another seventy thousand dollars of discarded tickets to build a dream home. But I honestly don't think I can beat that coma fact. It's too good. I'm gonna hand you the trophy.
Right now, Arnie to Warney, I got a bunch of coma facts for future episodes because I just feel like they always they always take it. But thank you. It is nice to end an episode about scratching an itch and feeling this satisfied. So we'll be back again next week with a brand new episode of part Time Genius in the meantime from Dylan, Mary Mango, and Me. Thank you so much for listening.
Part Time Genius is a production of Kaleidoscope and iHeartRadio. This show is hosted by Will Pearson and Me mongas Chatikler, and research by our good pal Mary Philip Sandy. Today's episode was engineered and produced by the wonderful of Dylan Fagan with support from Tyler Klang. The show is executive produced for iHeart by Katrina Norvell and Ali Perry, with social media support from Sasha Gay, Trustee r Pots and
buy any Shorty. For more podcasts from Kaleidoscope and iHeartRadio, visit the iHeartRadio app, Apple Podcasts, or wherever you listen to your favorite shows.