Why Skin Creams Give You Rashes

Why Skin Creams Give You Rashes

Thanks to Brilliant for supporting this episode
of SciShow. Go to Brilliant.org/SciShow if you’re interested
in investing in your STEM skills this year. [ ♪INTRO ] If you’ve ever ended up with a nasty rash
from using skincare products, especially oily or heavily scented ones, you’re not the
only one. A lot of people react to certain compounds
found in these products. Around 50% of people who use these products
will experience this allergic reaction, known as contact dermatitis. But researchers may have finally figured out
why these pesky rashes happen — and how to prevent them. Right now, the main way to treat contact dermatitis
it is to just avoid products containing certain chemicals. But if you’ve ever had this problem, you
know that’s a long list. And before now, scientists simply didn’t
understand how these rashes happen. See, allergic reactions are often triggered
by specific molecules called peptides. Those peptides trigger immune cells known
as T cells. But skincare products don’t typically have
those kinds of peptides in them. What’s more, the molecules they do have
are thought to be too small to be seen by T cells. But last week in a paper published in the
journal Science Immunology, researchers showed that a molecule found in our skin called CD1a
binds to certain skincare chemicals, making them visible to T cells. It basically rats them out to our immune system. The researchers identified several common
skincare substances that were able to cause a T cell response by binding with CD1a. Two molecules found in a commonly used vanilla-scented
oil, benzyl benzoate and benzyl cinnamate, got T-cells fired up when they were bound
with CD1a. The researchers looked even more closely at
another allergen known as farnesol. They found that rather than just sitting on
the surface of CD1a, it actually binds deep inside it , displacing natural skin oils that
would normally be there. That meant T cells weren’t simply recognizing
the chemical structure of farnesol on CD1a, but instead changes to the shape of CD1a itself. The researchers believe they might be able
to identify other compounds that can compete with farnesol for a spot binding to CD1a without
causing an immune response, offering some hope for preventing contact dermatitis. Another idea getting a lot of attention this
month comes from a pair of papers that claim to show how artificial intelligence can be
trained to detect cancer more efficiently than doctors. The first study, published last week in the
journal Nature, outlined an algorithm for detecting breast cancer from mammograms, which
are essentially x-rays of breast tissue. Researchers first trained the AI to recognize
cancer by showing it tens of thousands of mammograms from women in the US and UK with
a confirmed diagnosis. They then tested the AI on different datasets
of around 26,000 UK women and 3,000 US women and compared its results with the initial
diagnosis made by expert radiologists. The algorithm caught cancer on images where
it had been missed by the doctors who initially examined those mammograms. That will be a false negative,when we are
saying it isn’t there, but actually is. And it reduced false negatives by 9.4% for
the US dataset and 2.7% for the UK dataset. UK doctors always get a second opinion, which
might help explain the difference. Which is great, because doctors can miss up
to one in every five cases of breast cancer. So even a few percentage points could be helpful. The AI also lowered the rate of false positives
— where it looks like cancer is there but it actually isn’t — by around five percent
for the US group and one percent for the UK group. The second study, published this week in Nature
Medicine, used a similar method to train an AI to detect brain cancer. Researchers trained their AI on a dataset
of 2.5 million images of brain tissue from several hundred patients. But when it came to testing the AI, these
researchers did it in real time. They took two samples of brain tissue from
278 patients during surgery and gave one to their AI and one to a team of pathologists. The computer would first create detailed images
of the brain tissue and then analyze them using an algorithm. The humans would go off to the lab and look
at the samples the old-fashioned way, using a microscope. The AI did slightly better than the experts
here too, getting the diagnosis right 94.6% of the time compared to 93.9% of the time
for the humans. But what was really amazing about this technique
was its speed. The AI could predict brain cancer right there
in the operating room in around two and a half minutes, instead of roughly 30 minutes
it would take humans to do it. Which is great, because when doctors are operating
on your brain, they want to be really sure about their diagnosis. Now these studies don’t mean cancer diagnosis
is solved forever. One concern about algorithms in general is
that they’re only as good as the dataset they’re trained on. So if the dataset doesn’t include people
of different races or sexes, then the AI might not work as well for those groups of people
— like if the disease manifests itself differently in, say, men with breast cancer. They also wouldn’t work for diagnosing rare
tumors because there isn’t enough data to use for training the algorithms. Plus, it’s currently unclear exactly how
to use AIs in real-life hospital scenarios. Doctors could use them alongside their own
expertise to help them diagnose disease. However, a 2015 study suggested that other
computer-aided methods of detecting breast cancer didn’t improve accuracy, and may
even have made things worse. In addition, some physicians have raised questions
about these studies, suggesting that we should be identifying patients with dangerous but
curable cancers, not teaching AIs to find as many as possible. Especially when those lesions could be harmless,
leading to unnecessary treatment. In other words, the question no longer seems
to be whether we can train AIs to help us find cancer, but how they should be used to do that. If you’re interested in understanding more
about how the AIs we talked about today can detect cancer, you might like the computer
science courses over on Brilliant.org. They even have a machine learning course,
which will show you how computers learn, and why training them is so important. In addition to computer science, Brilliant
offers courses related to science, engineering, and math. They’re a great way to understand the world
better in the new year. They’re designed by talented educators and
lifelong learners from top institutions, so you know they know how to make things stick. And courses are even available offline via
Brilliant’s iOS and Android apps. The first 200 people to sign up at Brilliant.org/SciShow
will get 20% off an annual Premium subscription. And by checking them out, you’re also supporting
SciShow — so thanks! [ ♪OUTRO ]

100 thoughts to “Why Skin Creams Give You Rashes”

  1. Go to http://Brilliant.org/SciShow to try their machine learning course. The first 200 subscribers get 20% off an annual Premium subscription.

  2. 1:55 In general, binding of a ligand to a receptor causes the receptor to change its shape. The change in shape is what then triggers the response to the ligand. In this case the binding site may have been unusual for that protein, but cells detecting changes to the shape of a receptor is the normal way for this to work

  3. I get painful and itchy blisters from the adhesive on adhesive dressings, EKG leads, sports tape, and other such things. Also, a lot of sporty watches have silicone-rubber watchbands, and those also give me the same kind of rash. Creams containing hydrocortisone or benadryl don't relieve the rash.

  4. 50% get contact dermatitis from skin creams? That number is CRAZY high! I've never even heard of this. At most, I've heard the argument that using skin creams is sort of "addictive", that it somehow stops your natural skin oils, forcing you to keep using skin cream, or you'll dry out, but I never bothered to confirm this. If 50% get a rash from using skin cream, I don't understand how the product could even be on the market…

  5. Why do you need a skin cream if the skin doesn't already have an issue? And at that point whatever you use should be dermatologist-recommended… but oh wait… American healthcare

    All we have is universal functions that use weight matrix multiplication, to match input patterns to output patterns.
    Yes, the entire shady sub-industry has been lying to you. To catch clueless investors and rip off their money.
    I wrote more realistic neural net simulations in my teenage years in the 90s. But realistic simulations are very slow in comparison, allowing far too few neurons for anything resembling intellience. But at least they aren't a complete lie.

  7. I'm actually allergic to dimethicome, which sucks because it's in eyeshadows/powders as well as a lot of lotions. Also shaving cream. I used to think shaving your legs just made your body itchy, red, and crustiesh. Nope. Just me.

  8. AI May be able to detect breast cancer, but I have a better skill; If you just show me a picture of your breasts, I can tell you, if they're nice or not.

  9. Given basically every ointment, vitamin cream, balm, and so forth (EVEN 'pure Vitamen E cream" breaks my arms out in really.. .disturbing sorts of rashes to the point the only thing that seems to NOT break me out is petroleum jelly?

    This video is highly relevant to my interests.

  10. Im sorry. How can 50% of the people who use the product receive rashes or allergic reactions be a viable product that made it to market?

  11. ok… 20 years after I mostly gave up on makeup and facial cleansers and most lotions, something has been found. Yay.

  12. Lies. US healthcare 1,345.76x better than Everyone.

    I believe lobbyists amd shills anyday over some "science" malarky.


  13. I can't use any hand cream with sandalwood or primrose oil in, at least that's what I thought, but I now think it's the additives, from what you've just said.

  14. One of the biggest take aways seems to be 'on really important tests a routine second opinion seems like a really good idea, and is fairly easy to implement' – so why aren't they done else where??

  15. Patient: Every cream I put on my skin gives me a rash.
    Half-listening doctor: Uh-huh, a rash… this will clear that up. Here's a prescription for a cream.

  16. What's really frustrating is getting contact dermatitis but only in certain spots. I have an autoimmune disorder where I need to sometimes wear bandages under my arms, but after mere hours they become irritated, sore and even tear my skin. However, else where on my body bandaids don't have any side effect.
    #scishow can you explain this in a video?

  17. The answer is the bloody perfumes. I hate smelly skin creams, I get both contact, and regular dermatitis. I love sensitive or scent free options, they're all I can use.

  18. The fact that the cancer-detecting AI did the same thing for the US and UK and improved the US more than the UK shows how unnecessarily behind the US is in existing medical practices

  19. So doctors in the UK are better than doctors in America. Makes sense cuz most doctors in America only care about money. I know because my sister and brother in law are doctors in America.

  20. I never had rash using skin cream (and I use some often as my job make my hands dry as hell) but maybe that's because I avoid those with perfumes
    as much as possible as I got a pretty sensitive nose and heavy smells annoyed me. Or maybe I am just lucky.

  21. Sounds like a lot of cancer doctors don't like the chance of computer AI taking their income away … Where have I heard that before ???

  22. Should start training AI on blood work, vitals, and literally anything else possible to be able to diagnose pancreatic cancer sooner than haooens now

  23. FYI – farnesol is a naturally-occurring long-chain (16-carbon) organic "bio"chemical, no harm no foul https://en.wikipedia.org/wiki/Farnesol
    HOWEVER its also biochemically related to acyclic sesquiterpenoids which when doubled form 30-carbon squalene a steroid precursor and potent allergen adjuvant added to vaccines to make our bodies elicit a stronger immune response to the pathogen being immunized against
    IOW acquired contact dermatitis may be a very unpleasant side-effect of getting shots
    And as a perfume additive may also be linked to the deadly scented vaping e-cigarette epidemic of irreversible lung damage? Perhaps rather than developing new Rx to combat natural "effect" better to regulate "cause" ie disproportionate (ie unnnatural) application in commercial manufacturing?

  24. Probably completely unrelated, but nonetheless I have a personal story about AI diagnosing cancer. Believe it or not, Bixby vision on samsung mobiles diagnosed my grandmas skin cancer on her arm and face by matching images with those found online! It came back with the exact right cancer type and everything. Total fluke, obviously, but it warned us early and we sorted it!! Was just a passing thought to try it. Very glad we did!

  25. Is the AI any better at finding lobular cell carcinoma? 10-15% of breast cancers tgat are very hard to find with imaging

  26. Me at the start : skin creams can give you rashes and here’s why.
    5 mins after zoning out : AI can detect cancer

    I have cancer??

  27. I think cancer-detecting AI would be good for at least extra screenings. You could just go to a place and get a quick screening in a couple of minutes instead of waiting hours for a doctor. Of course it wouldn't replace mandatory screenings and if you really do have a concern

  28. It is going to take a long time before we will have AIs in the hospitals. Just one wrong diagnosis from an AI and newspapers will attack that AI even though real doctors make millions false-negatives each day

  29. I think the section about how the training worked might have a mistake at 2:40. Generally your training sets will have both positive/negative samples you train against.

  30. AI even to assist diagnoses by flesh and blood professionals is a bad idea, because it automatically introduces at least some measure of confirmation bias.

  31. That's generally how small molecules are immunogenic. They have to bind to some protein to be detected by the immune system, doesn't have to be cd1A.

  32. I'd like to see the day when big pharmacies provide cure for cancer. I bet there is already such but it is not free to use for public because it would drop so many medical bills from people.

  33. For people who has problems, also look out for GERANIOL. Many people are allergic to it and it can cause a quite ugly reaction.

  34. So that's another thing where Britain's NHS is better than America's terrible capitalist healthcare system: cancer diagnoses (as well as many other procedures) always require a second opinion, whereas in America that costs extra.

  35. TLDR; Use hypoallergenic products!!
    As someone who's had to hear about contact dermatitis every day on his course for the past few months it's always weird to hear about it outside of my course. What I've learnt & general advice:
    Moisturisers and skincare are beneficial for your skin, go for the good brands without fragrances or preferably, the hypoallergenic products would be ideal as those are supposed to be used on sensitive skin that is prone to reacting to products. Also nurses and doctors can be very prone to contact dermatitis as you can also get it from washing your hands far too often. If you do wash your hands too often like that, use a moisturiser in between washes to help prevent contact dermatitis.

  36. Did the studies on the cancer detecting programs look at the rate of false positives? If the rate of false positives went up, then the results are less impressive.

  37. Facinating! AI will help all of us, help from cancer! Our natural brain being helped by our artificial one! Sweet!

  38. I had an allergic reaction to sunscreen that was so bad, my skin turned into bright red blisters, I spiked a fever, and a few days later, my skin started sloughing off in sheets. =/ I was on antibiotics for a long time afterward.

  39. The science, dermatology community have forgotton the most common misunderstood skin condition that is "Rosacea" it affects 30 million people. The most sensitive skin ever.

  40. Our 3 month old hasn't had any noticeable reactions to lotions or ointments. We are picky about what we use though. Although we have used, like, Johnsons baby lotion on rare occasions, (which if you read the ingredients is probably the worst lotion you could use for a baby) we mostly use just olive oil or a couple brands that make an unscented lotion with a non-petroleum based moisturizer, he always takes colloidal oatmeal baths too (even though he never had eczema its still great for your skin). I think the times he has used less than desirable skin creams has probably helped to build his immune system and he didn't have any noticeable reactions.
    Moisturizing is such a simple concept.
    All lotions do is block moisture from leaving the skin and add a little moisture as well. Make sure drink plenty of water so you have that moisture in the first place.
    Edit: I've been wondering if coconut oil 8s a good moisture, some health sites list the things in it that make it good for your skin, anyone have any insight?

  41. The concern that there might be lots of misdiagnoses when the dataset on a cancer is biased to a certain sex, age or other group and that rare cancers will be harder to diagnose are of course vaild.

    But these problems concern humans just as much. Still we can teach humans with a lot of time invested. AIs are pretty fast learners from what I get.

  42. wow please do more videos of skincare!! I love skincare but i also want to be aware of the ingredients in them, these videos are so informative

  43. Alternatively…you can stop giving enormous companies your money and rely on natural soaps and organic oils and emollients like shea or cocoa butter.

    May not work for everyone, but my ultra-sensitive, acne prone skin did a complete 180 when I stopped wearing foundation, and then using drugstore skincare products.

  44. Or you could just do what I do: mix your own skin care products from natural ingredients like jojoba oil, vitamin E oil, shea butter, beeswax, etc. The result is a thousand times better than consumer products.

  45. Given the skin is similar to the digestive system in some ways, but rarely considered so, the term "skin deep" can be vastly misinterpreted.

  46. As someone with dermatites : just don’t use overly scented skin creams. Go to the “dermatology tested” specifically made for ppl with allergies… if you have dermatites rashes you know tht it makes your skin dry af…

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