Allergies: The Science of Why Your Body Hates You 

“Just because someone had ONE good idea doesn’t mean ALL their ideas had merit” SAY IT LOUDER FOR THE PEOPLE IN THE BACK!!! (Also, as someone with some pretty extreme cat allergies, the opening of this video was physically painful for me)

Thank you for crediting Chicken as the primary contributor to the video. As any cat will attest, cats should always be primary.

it wasn't a failed experiment, it was an unexpected result.

I had NO idea that eczema gives way to particles through the skin which the body sees as invaders! That’s so fascinating! Thank you for sharing this, me and lots of my family have eczema so this is super helpful to know.

I was always told that if you had allergies and eczema than more times than not, you would also have the "cousin" asthma.

When I was young an allergy test told me I was allergic to dogs, cats, peanuts/soy, milk and dust mites. I broke out in hives whenever I was near any of these things, but I ate peanut butter by the spoonfull, my family always had pets both dogs and cats, and I was a pretty messy kid. I lived on benedryl but over time I stopped having reactions/hives and I've credited that to facing my allergies head on. I'm happy to see there was some actual science to that and not just a coincidence.

11:50 I started exposing my son to peanut butter orally by around 6 months. Now, 18 months old, PBJ are his favorite snack food.

When I started this video, I didn't expect to learn new stuff about my eczema. Really interesting!

What explains adult onset of allergies? I ate peanut & egg as a child - no problem. Now I'm allergic to a bunch of things including egg & I have eczema which is triggered by eating corn (tested positive for corn allergy with skin prick testing). I haven't tried eating peanuts since I can't eat other legumes (chickpeas, pinto beans, soy). I can eat almond butter so I'm happy about that. My daughter developed severe oral allergy syndrome & Celiac around the same time I developed allergies & eczema. We are both allergic to birch pollen. Weird coincidence - a few days ago I was thinking about making a small tent-like structure out of Tyvek and attaching it to my room Hepa filter to create a positive pressure filtered air chamber around my upper body when I sleep (sort of like an oxygen tent).

Allergies are weird & don’t always follow the rules. ☹️ I have cats. I’ve always had cats but my oldest daughter is slightly allergic to their dander. All four of them are allergic to dogs. Neither I nor my husband are allergic to either. Another daughter had very severe excema as a child. It has calmed down some but she doesn’t have seasonal allergies or food allergies (just the dog one). She does have very reactive asthma though, triggered by exercise or a cold or fumes/smog. I’m allergic to fresh tomatoes & the juice from a fresh tomato. First popped up when I was little & I developed severe hives not long after eating some. I kinda forgot I was allergic until I got my first job at a Subway, back when they sliced everything by hand. I sliced some up, got splattered by juice & broke out in an itchy rash up my arms. My mom reminded me that I’m allergic to tomatoes. 🤦🏽‍♀️. Even now I’ll break out into a faint rash on my chest if there are fresh tomatoes in a sauce or stir fry. I could always tolerate ketchup & tomato sauces (minus the chunks, of course) so I do agree that the small exposures over time have lessened the immune response. I don’t even bother telling people I’m allergic; I just don’t eat them, decline them or pick them out if I need to. I have environmental allergies, worse in the spring but otherwise all year. I only get excema flare ups if my allergies are strong.

I was raised in the NE. I never had allergies until I moved to southern Arizona. I'm 58, and have had cats my entire life. Never had a problem with them until I moved down here. What's really odd is that since allergies took over 24/7/365, I haven't had a cold in almost 40 years.

This was fascinating! Glad to hear that the "Clean Hypothesis" has been disproved, sort of. Really, really pleased to see the BUS finally being praised for once for the work it does when it comes to research and development. Especially in the Allergy field of medicine given how so many more children are being affected by this issue in today's modern world.

I was born and raised in California, I've lived here my whole life, and particularly in my childhood I spent plenty of time outdoors. However, much to my chagrin, I have suffered my whole adult life from allergies, specifically to the plants in my home state. It's an unfortunate reality for me, because as a baby I also suffered from several food allergies that my parents managed to rid me of through the kind of incremental exposure described in the video. But the plant allergies just won't go away. I have to take Cetirizine Hydrochloride every day and Astepro for the especially bad days.

So the "too clean ' hypothesis is being discarded in favour of the ' not being dirty enough ' hypothesis? Surely not just the same thing?

Always love the videos! Just retold all this to my partner. Minor nit: all the timeline dates seem off by a decade starting at 4:18 (eg 1546 is between 1540 and 1550)

It's so fascinating. I didn't develop an allergy to animal stuff (both cats and dogs) until I hit puberty. I always grew up with cats and dogs, and they often would sleep with us, we would pet them etc. But then one day, I noticed I was getting congested, watery eyes, and sneezing at bed time. After several months of wondering what is going on, I was home one day and I saw the family housecat sleeping on my pillow in my bedroom. I shooshed her off, swapped the pillowcase, and closed my door. No allergic reactions that night when I went to bed. Later I found through visiting the home of friends and family that the greater the concentration of animal dander? (honestly I'm not sure) the more severe the reaction. I even found that just petting a dog or cat and not washing my hands afterwards would cause me to sneeze or get watery eyes or experience congestion. I haven't been in a very highly animal laden space in a while, but it seems my reaction has tapered off somewhat, although I am very attentive to washing my hands after a pet a dog or cat. I like to hope that this allergy will just go away as mysteriously as it developed, but now I usually prepare if I know I'm going to be visiting someone's home who has a housepet that I bring some allergy meds.

I didn't learn about my problems with food until I was out of college (22.) Mom never mentioned my having skin problems. Now, in those critical first bunch of months - until I was close to 2, I lived in a state where corn consumption was not as much as it is today. Then we moved to Texas. I don't remember having issues with corn until I hit puberty. Now, I didn't connect my migraines with eating corn, but I will say that Mom made pancakes every Wednesday, and we used cheap syrup=corn syrup with artificial maple flavoring. I got sick every Wednesday, throwing up sick, severe headaches, etc. Even today, if I smell artificial maple flavoring I get queasy. I have no problem with real maple smell or taste. At about 30, after spending 8 years mostly avoiding corn protein, if I got into it, I became really sick: tunnel vision, dizzy, migraines, and extreme inflammation in my body. I could barely eat since if I ate more than a few bites of anything more than saltine crackers, I got sick. And yet, I got tested last year for food allergies and they didn't find anything... so, my body won't let me even smell corn without reacting then, if I'm not allergic, what am I? My most serious reaction I ever got I didn't even know I had gotten into corn until after I started reacting.

So to prevent cat allergy you would have to eat cats as a kid? 😂

Awesome video! I gotta shout out to the video editor, Claire! Fantastic job!

My kiddo would have eczema on her legs. My first response was to put cortisone on it. The moment she was able to, she ate peanuts. Weirdly, she gets contact dermatitis with olives and olive oil, so I assumed she is allergic to olives (like her great grandma on her dad's side). As a baby just barely eating solids, we learned this because my mother in law gave her a piece of her firehouse sub sandwich, which was drenched in olive oil, and she got rashes everywhere it touched. She only really nibbled the sandwich, and everywhere near her mouth was rashy. She has had this response multiple times to light exposure of olives and olive oil. Wonder how much genetics may play a role

Omg when you rubbed face on cat I was cringing so hard haha. I mean I don’t have the same cat allergy but if I did that with juniper I’d be miserable for weeks!

This was so good. The Eczema revelation blew my mind!

Well, here is another thing. In my childhood, I had two cats. Both of them were completely fine to me. However, once the first one died, and the second died of poisoning, I developed allergies later on. The thing is, for the past years, I have had a very difficult life. I was very stressed physically and mentally. So I suppose the stress changed my body - it took away from my life the animals that I loved. The same went for dogs, btw. It turned out that I had allergies to dust mites, too. But this case is weird because, as a kid, I did not wanna bother cleaning my desk from dust. Yet, here I am.

Beautiful Intro to a video I just love animals

Was literally battling with dust allergies this morning, very timely.

I love this video and the vibes of the production

I just have to say, I LOVE the rainbow glasses!

This was both a very well produced and SUPER interesting video - thank you for this!!

Dang, that conversation with Dr. Lack was insightful. I had never heard the "skin before gut" idea before but it sure makes a lot of sense. Though, no one tell the homeopaths about that peanut allergy treatment or we'll never hear the end of it 😜 I had never heard of the relationship between eczema and food allergies either. I suppose I should count myself lucky I didn't develop eczema until 10 or so because I also don't have any food allergies. Thanks for another excellent episode!

I always thought that the immune system is a bit like neutral networks, with adrenaline acting as "temperature", The more the organism is hyped up, it'll hallucinate more, and basically do any different kind of autoimmune shenanigans

Thanks for this episode!

Thanks! This is great info.

Outstanding episode! Learned a lot, enjoyed the humor. Keep em coming

Very informative.

Very interesting stuff! This my have given some insight into how certain issues crept in around the time I started working in food prep.

Another well made, informative, and fun video in this series! Also, shoutout to the video transitions, very creative haha.

loved this episode!

Thank you 🙏

Thank you

Minor quibble, the primary cat allergen is not their hair, but Fel d 1, a protein in their sebaceous secretions and saliva. It gets stuck to their dander, which then sticks to us or our clothes when we come into contact with them. Hairless cats like Sphynx aren’t considered hypoallergenic, while a long-haired cat breed like the Balinese is often considered less allergenic due to lower Fel d 1 levels.

Love this presenter ❤️

Fantastic stuff

This video has an Answer in Progress vibe to it. Especially the scene in front of a projector.

I love that the hygene hypothesis basically got an update with the old friends hypothesis. Also this video reminded me to get out the ergonomic mousepad I bought to keep something on my desk from triggering eczema in my wrist. >.> also guess where I get eczema? MY FINGERS!!!! 😭😭😭😭😭😭

What I'd be interested in is research into allergies and intolerances that seemingly spontaneously appear in adulthood. In my case, I developed a pepper and dairy protein allergy in my late 20s, likely triggered by a medication that seriously messed with my digestive system. Most of the effects recovered after I stopped that medication, but these two allergies have remained even though it's been a number of years since.

I would love to watch an episode about adult onset allergies. Also, love the Noo Works

Holy moly, wow! Thank you!

I have a ton of environmental allergies, including cats, dogs, horses, grass pollen, rag weed pollen. Most of those allergies were greatly reduced by therapy shots. The cat allergy was the only one that resisted the therapy. I did grow up out in the country around 2 cats, and it certainly didn't help. 🤷‍♂️ Also had an anaphylactic reaction to Candy Corn when I was 10. The allergy doctor thought it was probably Yellow #5 (tartrazine). To this day I have to avoid anything with yellow 5, otherwise I get major intestinal distress if eaten, or rashes if in shampoo or soap. Ironically, no allergies to nuts or shellfish. 🤷‍♂️🤣

Great video!

Fascinating info, especially the skin's role in immune responses.

so not actually important but it caught my eye- what's going on with the timeline visuals? you put 910 CE before 900 CE, 1546 after 1550, what is happening?

Love the idea of infinite wealth and just doing science. I used my GI bill to try and get a degree in physics, I got up to Physics 2 and Calculus 2 but ran out of money, at least I got an AA. I had an actual dream not too long ago that I won a hundred million dollars and just lived off the interest on it just living life as a career student. What a glorious dream.

Great video! ☀

As a life-long pollen allergy sufferer, I can say that I was definitely exposed to a lot of pollen, especially as a little kid, I grew up in New England and still reside there, and every single spring and summer I ran around outside barefoot much of the time. So being a free range kid back in the days when parents actually told kids, what are you doing inside? Go outside and just be home in time for dinner! And I didn't even need to be told that since I was lucky enough to grow up in a place with ample front and backyards so whenever it wasn't down pouring or snowing heavily I was taking my shoes and socks off and running around outside enjoying climbing trees and picking flowers that were abundant on my property. So it just never made any sense to me whenever someone said that the reason my body is allergic to pollen is because I wasn't exposed to it enough as a kid, since quite the opposite is true. Besides even if I grew up in a more urban area, pollen counts are still high in cities as well as more rural areas. There is another fascinating video that delves into the reasons behind some of the most common allergies and it describes a link between venom and other toxins evolving into allergies. This theory makes the most sense and it has to do with the way we humans have evolved. Wish they mentioned that here.

If not being exposed to peanuts early on leads to allergies, what about having parents with particular diets? For example, vegan parents so the child is not exposed to eggs. Will they later have allergic reactions to non-vegan environments? What is it about peanuts that makes the body react whereas other objects not experienced in childhood do not have the same effect?

I used to have cat allergies but now that I take care of a stray cat and often visit my brother, who also used to have cat allergies but now owns several cats, I am no longer allergic to cats.

not just my body : my mind too

I'm confused. The presenter stated "the hygiene hypothesis is outdated," but then went on to essentially explain that we need "old friends" which sounded a LOT like the hygiene hypothesis. Can anyone in the comments clarify?

I Like this video and I need a lot of it! Please make more 💙🤝🏻

This was fascinating! Thank you so much for looking into this and presenting it! I have environmental allergies that developed over time. I'm even allergic to my own cats! Since Hell would have to freeze over before I ever give up having kitties in my life, I always figured I'd just have to suffer with the runny, itchy eyes and nose, the sneezing, and the horrifically itchy skin for the rest of my life. Now, I was recently diagnosed with eczema (after years of just being told I was itchy because I have "dry skin"), so maybe I'll bring this video up whenever I go see an allergist. Again, thank you so, so much for presenting this. I never knew allergies were this complex. Also, thank you for giving me hope that one day, I will be able to live without itching, sneezing, and using an entire box of Kleenex in three days. Maybe it will make colds, the flu, and other respiratory illnesses less intense, too. :)

Question as to why Chu et al from 2019, the survey paper looking at oral immunotherapy studies for peanut allergies that found that it didn't have a positive effect, wasn't mentioned. Was there a problem with the study that makes it not relevant to Dr. Lack's comments on peanut allergies, or is he just continuing the work from that paper, looking for the "safer peanut allergy treatment approaches"?

Maren is just the best science educator on RU-vid.

So how do we get the word out about preventing/treating allergies based on the new findings?

I haven't read all the comments, so I don't know if it's already been asked -- does this mean we can ingest orally small doses of poison ivy and acquire immunity to it? Or is the reaction to poison ivy a different type of bodily response?

Hey Maren, missed you!

So I've been sleeping with a HEPA filter on for a while & my hayfever has definitely improved this year.

What about allergies that are acquired? I hung out with cats on a regular basis growing up, but suddenly, in my mid 20s, I couldn’t be around them for more than 5-10 minutes without an allergic reaction.

I'm severely allergic to cats to the point of allergic asthma I have 3 cats 🙃

This is all really interesting. I wonder how adult onset allergies work, though. I had skin allergies as a kid, but didn't have any noticeable respiratory allergies until I reached adulthood. It seems like quantity of exposure might be at play for me, since I developed a cat allergy while regularly volunteering at a shelter, and pollen counts have been increasing due to global warming. I've also had a skin allergy to grass since I was a baby, and now I suspect the pollen that I'm allergic to may be grass, due to pollen counts on days when my allergies were particularly bad, so that could just be an evolution of the original allergy. Still, I lived with cats for over a decade before I had any signs of allergies, which just seems strange to me (though I didn't have regular exposure as an infant).

You said that allergies happen when the first time you interact with something that's when you could get the allergy.But I only develpoed my allergies at the age of 10 or so, after a long time of playing outside and playing wioth dogs as a kid. Could you explain this please? To be spefific, I have pollen and fur allergies.

Not every reaction of your body has to be an allergic one. You can also be oversensitive to a certain substance. I for example am not allergic to pollen (it has been tested) but I developed more or less the same symptoms like sneezing, sore throat etc. when I come in contact with certain pollen. I heed the same drugs as for hai fever.

Been doing sublingual immunotherapy for cat and dog allergies before I started I had asthma but now I have a puppy

Hello! Bit of an odd question but… I’ve been trying to raise awareness about cacti’s extinction crisis by rping as a saguaro online for over 3 years now.

I might be wrong about this but for some reason in this video the left audio channel volume is lower than the right. Some editing mistake which got overlooked I think.

I was glad to hear that they are putting a particular focus on detecting eczema on dark skin. Especially because if it can detect eczema on a black person it 100% also could on my pasty-ass skin tone.

Thanks pbs. Now i will start my cat hair diet. Not looking forward to the hair balls but would love to snuggle my fur babies

Wow, I had environmental allergies years ago and I also have eczema. I was curious if there was a connection. I pretty much couldn't avoid dust and pollen so I guess I eventually dosed myself into immunity. Although I grew up loving shrimp and now as an adult I'm allergic. :\

So glad i dont have allergies or am allergic to anything that i know of. Im 40 so i think i am good.

The "old friends" and "too much clean" models seem basically the same. The "old friends" sound a lot like germs that are lacking in the "too much clean" model.

You have been killing it with this production quality and editing style!

Interesting! I was a pretty adventurous child and have a high number of allergies, but, oddly, none to food. Not sure what happened there haha. Also, please note the C in eczema (not eGGzema). 👍🏻

The interesting thing is that the "ppl aren't exposed to enough germs these days" crowd is _almost_ right. They're just wrong about exactly what it is that kids need to be exposed to - kids need to be exposed to allergens. It also explains why my mom is mildly allergic to cats, but both my brother and I have no allergies whatsoever to cats. We have had cats ever since I can remember. I know I've eaten and drank cat hair plenty of time both when I was young and probably even today.

Cute cat!!!

i had a cat as a young kid and the developed a cat allergy in my teens 😭

I have my own theory towards why I developed allergies towards birch pollen and stone fruits such as apples and cherries in my early 20s. I think it is because I ate too many bad apples and so on that had mould on or in them as a poor student. No idea how I could test my theory though

Why does my cat chatter at me every time I sneeze? Is he mocking me?

I grew up with cats why am I so allergic???😭 I also was quite rashy when I was a baby and growing up, I've now got eczema on my face and hands and arms (yay, lol) and a killer shellfish allergy but I'm also convinced that the dust/pollen just wants to kill me but hasn't _quite_ figured out how yet. Maybe if they knew about these various things when I was a baby... or like wanted to treat any of it instead of insisting that I have no allergies and I was just making up struggling to breath when eating shrimp for attention???? Bad parenting, it was the style at the time.

I am like her with cats only worse. I love long hairs but my eyes turn red and swell up and I sneeze uncontrollably after being around a cat for any amount of time and being in a home with a cat even without the cat present is no better.

I have pollen allergies, and when I was younger also food allergies to apples, tomatoes and such, probably due to a cross-allergy with the pollen. I got itchy mouth when I ate the foods that caused the allergy, but nothing more serious than that. However, I kept eating those things, even though it sometimes was very annoying for the following hour or so due to the itchiness. Today I have no food allergies any more! The pollen allergies persist, maybe I should start eating pollen 🤔 (Note: I don't suggest anyone with dangerous food allergies to start self-experimenting with desensitization, it can be dangerous)

And now it's ALL been disproven by someone with an internet connection and a disproportionate love of kale smoothies.

Completely unrelated, but I need a link to those rainbow frames

Thanks for a fantastic video! All hail the Algorithm!

Drug Desensitization in a hospital setting is quite interesting as well

Nice glasses.

A good excuse to send yourself to Paris...

Me, who grew up on a farm and still ended up with eczema, food allergies, and a cat allergy: 🤡

Okay, so you've talked about treating food allergies - how about environmental allergies? I developed severe cat allergies during puberty (and later also developed severe dog allergies, though not as severe as my cat allergies), and it's only gotten worse over time. Presumably eating small microdoses of cat isn't going to help me, so...

My cat hates when I sneeze too! He glares at me and chatters.

Wait…. So to help reduce or eliminate allergies you can eat the allergen? So there might actually be something to the folk-medicine remedy of eating honey of bees that have fed on the flowers you are allergic to?!?!

So we’re supposed to lick cats then. Got it…