5 Things Your Hair Can Tell You About Your Health
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5 Things Your Hair Can Tell You About Your Health


[ intro ] If you’ve ever dyed your hair the colors
of the rainbow, or gotten a dramatic updo for a special event, you know that we often use hair for more than
just keeping our heads warm. It can be an expression of our personalities,
too. But how your hair grows — or doesn’t — can
also be a sign about your personal health. And while that’s really convenient and everything,
it’s also… pretty weird. Like, your hair is basically just a bunch
of protein clumps, so it doesn’t seem like it should be able
to tell you about other things happening in your body. But in reality, it’s affected by all kinds of systems. So from dandruff to hair loss, here are five
hair symptoms that can tell you about your health. In most cases, dandruff isn’t anything to
worry about. It’s often caused by a dry scalp, and can
be fixed with special shampoos. But it’s still worth paying attention to, because some kinds of dandruff can be a signal
that something else is going on. For example, one of the main symptoms of a
condition called seborrheic dermatitis is large, greasy, sometimes yellow dandruff flakes. It also typically includes scaly patches on
the scalp and redness on the skin, and in infants, it’s often called cradle cap. This condition can impact other areas on the
body, but it’s often focused on the scalp because
of all the sebaceous glands found there. These are openings in the skin that produce
an oily substance, sebum, that naturally moisturizes skin and hair. This type of dermatitis can happen to people
of all ages, and to be clear, it’s not caused by poor
personal hygiene — or allergies. Many factors seem to work together to cause
it, including naturally-occurring yeast found
on the skin, called Malassezia. This yeast normally just feeds on sebum and
minds its own business, but researchers suspect it can also cause
problems. They’re still debating exactly how it does
this, but it might be that an excess amount of yeast
triggers a response from the immune system. Or maybe someone just has a general imbalance
of microbes on their scalp. Regardless, it can be an itchy and sometimes
uncomfortable experience, and doctors usually have a way to treat it
— like by prescribing an antifungal medication. So if your scalp begins shedding, maybe listen
to what it has to say. There’s nothing embarrassing about dandruff,
people. Often, if you notice something troubling about
your hair — besides whether or not you’re having a bad
hair day — it has to do with losing or gaining it in
ways you wouldn’t expect. That’s because, generally speaking, hair
grows on a fairly predictable cycle with three main phases. First, there’s the anagen phase, where your scalp hair is growing about a centimeter
every month. Then, there’s the catagen phase, where growth
is beginning to stop, and finally, the telogen phase, where activity
in your hair follicles has completely halted. Like with dandruff, hair loss is often totally
normal. The average person loses around 100 hairs
a day just thanks to that normal growth cycle and there are plenty of common genetic reasons
to start developing a bald spot or thinning hair. But if a lot of it starts falling out pretty
suddenly that could be a sign of something more significant. For example, if you frequently wear your hair
in tight ponytails or braids, you might notice hair falling out due to a
condition called traction alopecia. It’s a gradual hair loss that’s caused
by pulling on your hair follicles too often, but if it’s caught early, it’s pretty
easy to fix by switching to a looser hairstyle. There are also more surprising reasons hair
can start to fall out, though — like a disorder called telogen effluvium,
where hair prematurely shifts into the telogen phase. This causes it to rapidly fall out, sometimes
by the handful. It can be triggered by all kinds of factors,
from severe illness to medication to plain old psychological stress. But generally, it happens because when the
body is under stress it adjusts the amounts of hormones and chemicals
it releases. For example, if someone has a fever, their
symptoms are caused by cytokine molecules. They’re responsible for telling the body
to raise its temperature in order to fight off sickness. But as a side effect, those cytokines can
also tell the cells in hair follicles to die, causing an early telogen phase. Even though that has nothing to do with a
fever. These various changes are designed to help
the body deal with whatever situation it’s in, but they can also come with consequences. Thankfully, this shedding usually decreases
over time, once the primary stressor has been resolved. And in most cases, the hair grows back normally. Now, there are also a few conditions that
cause especially unusual hair loss — like in weird patterns, or unusually smooth
spots. Like, in up to 7% of cases, the secondary
stage of syphilis can cause a unique baldness pattern that kind of looks like a moth-eaten
sweater — although doctors are still trying to understand
why. There’s also a condition called alopecia
areata, which creates smooth, semi-round bald patches. Although they’re most notable on the scalp, they can happen anywhere on the body. And they can happen suddenly, too, developing
over the course of only a few days, which makes them different from your typical
bald spot. This time, though, it isn’t mainly because
of stress. Alopecia areata is thought to be an autoimmune
disorder, and happens when the body attacks its own hair follicles. Normally, your immune system protects you
against things like viruses and bacteria. But sometimes, it will mistake healthy cells
for invaders, and that’s when an autoimmune disorder develops. In the case of alopecia areata, researchers
think that a type of white blood cell called T cells are sent to attack hair follicles based on what they’ve seen in experiments
with mice. They’re still pinning down the details but it’s possible that an imbalance between
types of T cells could cause the attack. In some cases, scientists have noticed that
patients with this condition have too many helper T cells which trigger immune system responses, and
not enough regulatory ones. Still, regardless of what causes the attack it ultimately leads to the body producing
signaling molecules that tell hair to fall out. Researchers suspect that the odds of developing
this condition might have to do with someone’s genetic makeup since people with a family history of other
autoimmune disorders seem to have a higher risk of developing it. And for those genetically predisposed to the
disease various environmental factors that cause stress
on the body may trigger alopecia areata to occur. Now, on the other side of the spectrum, you
might sometimes notice extra hair growing where it didn’t before. This can be caused by multiple things that
are usually pretty easy to identify depending on factors like your age and sex. For example, menopause causes someone’s
estrogen levels to drop which can lead to an excess of testosterone. And that can cause more hair to grow in unusual
spots, or the hair to come in thicker or darker. Alternatively, it could just be a random mutation. If you find a sudden dark hair somewhere you
didn’t expect, it might be because the hair cells mutated during growth. There are some conditions, though, that cause
different types of hair to grow on your body. One is called acquired hypertrichosis lanuginosa. It’s a long a name that basically means
fine, unpigmented hair — called lanugo hair — just starts showing up in various spots. Normally, you don’t see lanugo hair much. Its main job is to protect a fetus during
development and it’s typically shed before someone is
born. But sometimes, it can regrow later in life
in response to major changes happening in the body. This condition is sometimes associated with
lymphoma or other various cancers but it’s more frequently known as a symptom
of anorexia nervosa. Those with the disorder might see these fine
hairs appear on their limbs, stomach, or back. It’s possible that the body starts growing
it to keep warm in the absence of body fat. But other researchers have suggested it could
be a consequence of decreased thyroid activity, which can also happen in anorexia patients. Of course, like other hair symptoms, the presence
of lanugo hair doesn’t mean someone is dealing with any of these conditions. This kind of hair growth can also be a side
effect of a wide range of drugs, from immunosuppressants to anti-seizure medication. Finally, besides excess hair growth, there
are also a few reasons for hair to come in thicker. A big one is pregnancy. Higher estrogen levels during pregnancy trigger
hair to stay in the anagen phase for longer, which means someone ends up with thicker locks. It also explains why hair loss after giving
birth is common, when those estrogen levels go down. There’s also another type of hair growth
that can be triggered by everything from polycystic ovary syndrome to medication, and it’s called
hirsutism. Although it can happen in all sexes, it’s
most common in biosex females. It causes them to grow hair in what’s typically
considered a male growth pattern with thicker hair developing in areas like
the chest, upper lip, and jawline. This growth is the result of the conversion
of fine vellus hairs — the peach-fuzz type hair all over someone’s
body — into coarse terminal hairs. And although it can be caused by multiple
conditions or medicines it’s broadly linked to an increase in androgens. These are hormones that play a part in traditionally
male traits and reproductive activity. Hirsutism can sometimes happen randomly, especially
in those of Middle Eastern, Mediterranean, or South Asian descent. But if it’s accompanied by other symptoms
— like increased acne or voice changes — doctors might take a closer look to make sure
it’s not a sign of a more serious hormone imbalance. Speaking of doctors, you’ve probably noticed
that it’s impossible to diagnose health issues just by looking at your hair, because the symptoms are shared with such
a wide range of causes. That means that, while changes in your hair can give you a
heads up that something might not be right, what you see in the bathroom mirror shouldn’t
be your final diagnosis. It’s fascinating that so many different
things throughout the body — from your immune system to your hormones
— can affect something as simple as your hair. But if your hair is trying to tell you something,
please don’t diagnose yourself using the Internet. Instead, this is the reason actual doctors
exist and you should go talk to them. Thanks for watching this episode of SciShow! If you want to learn more about what your
body can tell you about your health — including why you keep getting those weird
lines on your fingernails — you can watch our episode about nails after
this. [ outro ]

100 Comments

  • victorpapaavp

    I have exactly 0 non black hairs on top of my head, but there's dozens of blonde and red hairs in my beard. Any idea why?

    Am I a closet ginger?

  • chickenfoot87

    A fever changing the hair can happen in animals too. It's called a fever coat and can cause kittens and puppies to have a weird fluffy coat after an illness.

  • chickenfoot87

    I also have PCOS and it makes me grow a lot of body hair. I also have a deeper voice than is usual for a girl.

  • Joy Bradford

    No more tight ponytails for me. No wonder my hair brush is so full of hair when I am done brushing it! Thank you for your great videos!

  • Joshua D

    Remember, according to every advertisement featuring it, having visible dandruff means you will never get laid. The woman will see the flakes, have a disgusted expression, and walk away. Every time.

  • Pink Bunny

    I would love to have a looser hairstyle but its so frizzy that it has to be in a bun…. Well, gotta deal with a few hair falling out.

  • TheFourthWinchester

    I do not have the body of The Rock. I cannot afford to go bald 🙁 I recently lost a lot of hair due to Typhoid :/

  • Florin Curteanu

    How to get a thick healthy hair:
    – Eat healthy (for a light blood);
    – Hidratare enough (2 litres of water per day);
    – Don't stress or get upset (because the stress hormones attack the hair follicles);
    – Go outside and get some vitamin D (but don't stay to much in the sun), or take vitamin D medicals if you are a vampire;
    – Wash it 1-2 times a week, especially if work in dusty places (no more often);
    – Don't excess with the comb or with special sprays/gels (try to let the hair free, natural, to breathe);
    – Be happy and laugh often.

  • Thekrabbman

    If my scalp hurts a little after wearing a manbun (usually just after long periods of time), should I stop with the manbun or just use a "Lighter" bun?

  • lillypod21

    I learned a crapton about telogen effluvium after I started losing clumps of hair a few weeks after recovering from dengue fever. I know it's just hair and that it grows back, but suddenly losing that much hair so quickly is really distressing. It's been two years since the rapid hairloss stopped, but I feel like my hair has not gone back to how thick it was before TE.

  • GhormiBear

    I have PCOS and if i didn’t shave everyday I would have a beard
    it sucks and makes you feel less of a woman 😞

  • Greg West

    Back hair is not weird. I agree it looks awful, but there is a strong correlation between High functioning creative cognition and hirsuteness. https://www.independent.co.uk/news/the-hirsute-of-higher-intelligence-1328285.html

  • vamsi krishna sadhu

    Can you please make a video on ITP Idiopathic Thrombocytopenia Purpura. It is a rare auto immune disorder and there is no much information about it. Thanks.

  • Elizabeth Meier

    😲 I'm nearly positive the first one you talked about is what is wrong with my scalp. It's been an issue for years. I just thought I had really bad dandruff 🤷

  • Emelia Smith

    When I was in my teens I had a brief interesting period where two or three small patches of hair on my body just lost all pigmentation; My doctor couldn't work out why but put it down to some sort of stress reaction 🤷🏻‍♀️

    (The pigmentation never return to those patches either)

  • Danielle D

    I had adult cradle cap!!! It was so weird. I think it could've been partially because I'm a model, and people are always putting weird products in my hair that I have no control over. I also traveled a lot and lots of different phs in the water etc, i suppose could contribute to the microbiome. I also just think it's important to scrub your scalp a bit with your nails, I read somewhere that this causes irritation so I stopped scrubbing my scalp with my nails, just my fingertips, and the buildup became more severe. Sometimes you gotta just dig in there!! Hah.

  • Are Gup

    Am sorry but u really need to add other medical conditions and to go to ur dr for more deep eval.. Like a lot of dandruff for a person that never had it might be HIV sorry meant to say medical emergency symptoms.. or stop using others ppl brushes.. Ringworms causes bald patch on head.. ur body has a self warning signal to u to say hey go to the dr or something is wrong here do something before us to late. Just a little more in depth would b nice alway end with see a professional.. like excessive hiccups 4 days might also b a signal for the autoimmune disease hiv saying hey have this check out by a dr.. someone with halitosis should not blow food for a baby.. or kiss u u will get that bacteria .. meds can also do damage to the human system

  • Falbert Forester

    I disagree with the notes towards the end of, "It's impossible to diagnose conditions from your hair" – as I can recall reading about several cases where it's been proved that someone was poisoned with arsenic – provided by testing their hair.

  • Michael Seydor

    Thanks SciShow for talking about alopecia areata. I have alopecia universalis which is a form of AA with total hair loss over the entire body. AA is one of the least understood and under-researched autoimmune disorders out there since there is no physical pain/restrictions. However, the negative psychological and societal effects can lead many of us to develop mental illnesses among other side effects. Any coverage on our disorder is appreciated as we collectively are trying to create awareness to fast-track research and clinical trials. Woohoo!

  • TheMeganano

    I've been pretty self conscious about my hair ever since I was small. I've always had white hairs and I dunno why…

  • Rachel Swanson

    I have dandruff. It started around 12 years of age. I've tried all kinds of dandruff shampoos none work. I have to only shampoo my hair once a week sometimes twice. I use shampoos for Africans because they're not as drying on my scalp. I also have to oil my hair once a week to two weeks. My son whose reaching 12 years old just developed dandruff too. I think its a hormonal thing rather than a fungus thing as you mentioned. Why would it only start around the time hormones change in a person's body? I'm so tired of dealing with dandruff.

  • Ico

    Sometimes I get extremely stiff, translucent hairs on my arms (only ever noticed it on my arms) that are very easy to pull out and sometimes there’s are multiple coming from the same follicle. Does anyone know what this is or what causes it?

  • Feral Crafter

    Every time I go to a doctor, I'm billed thousands of dollars for a diagnosis of "I don't know" …. Sooo why go to a doctor?

  • David Oh

    I’ve noticed that ever since I started growing my hair longer, I’ve been losing a SIGNIFICANT amount of hair daily. I’m a male. Does anyone know why?

  • Sharon Johnston

    I actually have alopecia areata I always thought it was stress related. My dads a barber and in barber college he learned about hair disease and the way hair grows and he told me what it was and that it’s mostly stress related and it’ll grow back so I never really looked in to it I mean it’s probably only happened like 4 or 5 times in 3 years.

  • veksu9

    Dandruff is caused by fungus. In special shampoos there are ingredients which kill those microorganisms. You are missleading people…

  • TheSzyko

    Please make a video about why your turn down the music volume when backing into a parking lot ( and what science is behind it). Yeah for sure it´s because of focus, but why does everyone do it? Maybe there is more to it. Much love, thx for your show!

  • IncontrovertibleTruth

    Well many people look up things on the internet first because at least in America so many people can't afford health insurance also people want to be educated about what's going on with their bodies

  • Peldyn - Life with Cats

    I had a telogenic event and it was scary! Happened after I had a thyroidectomy. Lost most of my hair. Thankfully once my thyroid meds were adjusted my hair grew back.

  • Nikki Williamson

    My hair started falling out in 2017. It happened because I was very ill and on a lot of medications. I got better, came off the meds and it started to grow back thicker. Now I have a tonne of baby hairs that aren’t yet long enough to tie up but are long enough to get in my eyes…

  • edi

    Why are men and women storing fat differently. What´s the advantage of storing it mostly in the belly, rather than spread over a wider area? Since, we´re already on topic: why do many Afro-american women have butts that seem to defy gravity (not sagging, less bouncing and no moon-surface)?

  • Jeremy Pickett

    Too many comments way funnier than me 🙂 Thank you Sci, this happens to the best of us and shouldn't be feared. I had a severe health thing, three months later my hair fell out, three months after I am back to normal. Well, normalish 🙂

    Talk to your doc, and we dont judge.

  • Nishant Sengar

    Nicely explained, but what causes premature greying of hair, can that be treated? I have seen even the 5 years old kids start to have grey hair.. is it all diet dependent?

  • Hypatia Ravenclaw Sklodowska

    "your hair isn't just something that you have to deal with every morning" – first time someone accurately described hair imo

  • -

    One time I suddenly developed alopecia barbae which caused a small, circular bald spot in my beard (which was still visible even after shaving because it was completely hairless) and it was caused by stress and went away after a while.

  • Letolz Velostoll

    "menopause can affect someone's…" you can tell "menopause can affect a woman's…" is being avoided, because men can undergo menopause now.

  • Michael P.

    Going through the ninth month of tellogen effluvium, the hair has still not recovered. I've learned my lesson with stress.

  • Morris Chen

    Thank you for using trans/gender-inclusive language!! This just made me love you and your channel even more (which I didn't know was possible) <3 <3 <3

  • Maurice Spence

    I noticed I had alopecia areata after a visit to the barbershop. I thought I was aging way fast or something

  • MsMcmoe

    Hmm, didn't hear it mentioned that a persons' thyroid may be out of balance, or there's a nutritional/vitamin deficiency .

  • ღ Ashimari ღ

    I leave the floor coated in hair wherever I go but I have a super thick coat of hair, even with shoulder length, it takes a ton for it to dry

    It's been months like this and no notorious change, but as the video says, probably has to do with Ballet hahah

  • Liusila

    I’ve had dandruff and an itchy spot on my head. It really doesn’t respond to any shampoo and I know it’s part of a bigger thing because when it gets worse a few other areas around my body get really dry and start to itch. Wtf.

  • roronoazoro

    Each time I had move to a different country with a different climate my cells in my body mutated, and as side effects I have gained extra hair where I have never had before. It made me look more manly, so I am pretty much fine with it till women like it.

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