Information

Why does the scalp hair become grey first?


I understand that when the hair follicles produce less melanin or stop producing melanin altogether, hair becomes grey. But it seems like it is the scalp hair that becomes grey first. If follicles are producing less and less melanin, shouldn't the hair everywhere become gradually grey? Why is it that the scalp hair greys first?


The Biology, Structure, and Function of Hair

Heather L. Brannon, MD, is a family practice physician in Mauldin, South Carolina. She has been in practice for over 20 years.

Hair is much more complicated than it appears. It helps transmit sensory information. It acts as a barrier to foreign particles. It's an important part of the appearance and creates gender identity. It's also the only bodily structure that can completely renew itself without scarring. There is hair on almost every surface of the human body. Here's a complete overview of its biology, structure, and function.


Why Does Hair Change Colour And Turn Grey?

Most of us find our first “greys” by the time we turn 30, usually at the temples, then later, across the scalp. While many people find the salt and pepper look appealing, others go to great lengths to conceal these locks.

The grey hair “rule of thumb” is that by the age of 50, half of the population have lost the colour in 50% of their hair. When researchers tested this rule, they found that 74% of people aged between 45 and 65 had grey hair, with an average intensity of 27%.

Generally, men have more grey hair than women. Asians and Africans have less grey hair than Caucasians.

What Determines The Colour Of Hair?

Hair colour is produced by cells known as melanocytes, which migrate into the hair bulb as the hair follicles develop in utero. The melanocytes produce pigment that is incorporated into the growing hair fibres to produce hair in a bewildering array of natural shades.

Hair colour depends on the presence and ratios of two groups of melanins: eumelanins (brown and black pigments) and pheomelanins (red and yellow pigments). While variations in the ratio of these pigments can produce an large number of colours and tones, siblings often have strikingly similar hair colour.

Hair colour varies according to body site, with eyelashes being darkest because they contain high levels of eumalanin. Scalp hair is usually lighter than pubic hair, which often has a red tinge, due to the presence of more phaeomelanin pigments. A red tinge is also common in underarm and beard hair, even in people with essentially brown hair on their scalp.

Hormones such as melanocyte-stimulating hormone can darken light hair, as can high levels of oestrogen and progesterone, which are produced in pregnancy. Certain drugs such as those to prevent malaria can lighten hair, while some epilepsy medications can darken it.

Blond children tend to see their hair darken around the age or seven or eight. The mechanism for this is unknown and probably not related to hormones, as the darkening precedes puberty by a number of years.

New parents often find the first coat of their baby’s hair is darker than expected. It is not until this first hair is shed and replaced, at around eight to 12 months of age, that you get a clear indication of their hair colour.

Human hair growth is cyclical. During the anagen phase, hair grows continuously at a rate of 1cm per month. Anagen can last three to five years on the scalp and produce hair that grows to between 36 to 60cm in length.

At the end of the anagen phase, the follicle turns off, hair growth stops and remains off for the three months. Towards the end of this resting (telogen) phase, the hair is shed and the follicle remains empty until the anagen phase of the cycle restarts.

Pigment production also turns on and off in rhythm with the hair cycle. When pigment cells turn off at the end of one hair cycle and fail to turn back on with the onset of the next, hair becomes grey.

Losing Colour

Genetic factors appear to be important in determining when we turn grey. Identical twins seem to go grey at a similar age, rate and pattern, however we’re yet to identify the controlling genes.

There is no evidence to link the onset of greying to stress, diet or lifestyle. Certain autoimmune diseases such as vitiligo and alopecia areata can damage pigment cells and induce greying. However, these conditions are uncommon and can explain only a tiny fraction of greying.

Early greying occurs in premature ageing syndromes such as Hutchinson’s-progeria and Werner syndrome, where every aspect ageing in the body is accelerated. Premature greying can also be seen in people affected by pernicious anaemia, autoimmune thyroid disease or Down syndrome.

So, why doesn’t pigment production turn back on?

At the end of each hair cycle, some pigment-producing melanocytes become damaged and die. If the melanocyte stem cell reservoir at the top of the hair follicle can replenish the bulb, this keeps pigment production going. But when the reservoir of stem cells is exhausted, pigment production stops and the hair turns grey.

Scientists have long known that in order to prevent hair from going grey they would need to either prolong the life of the melanocytes in the hair bulb – by protecting them from injury – or expand the melanocyte stem cell reservoir in the upper or top region of the hair follicle so they continue to replace lost pigment cells.

A group of French scientists have identified a new series of agents that protect hair follicle melanocytes from damage at the end of the hair cycle. This enables pigment production to restart as soon as the next hair cycle begins.

The agents work by mimicking the action of an enzyme called DOPAchrome tautomerase. This enzyme is the naturally occurring antioxidant in the hair bulb that protects melanocytes from oxidative damage. By duplicating the effects of DOPAchrome tautomerase, melanocyte metabolism and survival improves.

The new agents are being formulated into a product that can be applied as a spray-on serum or shampoo. But they won’t re-colour grey hair or bring back the dead cells that produce hair colour. Instead, they protect your melanocytes.

So for those who cannot find it within themselves to embrace the salt and pepper look, new options are on the horizon.

This article was originally published on The Conversation. Read the original article.


Why Does Hair Turn Grey?

Your hair color is produced by cells at the base of each hair follicle. These cells make melanin pigments and feed these through to the hair root.

The pigment color you produce is genetically determined. Red melanin makes your natural hair color a gold, auburn, or red. Black melanin produces hair that is brown or black. Pale melanin, which is concentrated in the spongy core of the hair shaft, rather than the outer cortex, causes your natural color to be more honeyed or blonde.

Hair turns grey due to an age-related decrease in the activity of an enzyme called tyrosinase. This enzyme produces melanin from an amino acid called tyrosine.

The age at which your hair loses color is genetically determined and a few lucky people may retain their hair shade throughout life.

If your hair is grey, then some pigment is still present within the hair. If your hair is totally devoid of pigment, it becomes transparent and reflects light to appear snow white.


You might just experience a breakthrough

If you decide to give the "No Poo" movement a go, you may just experience a total hair breakthrough. Once you're several weeks in, your hair may start readjusting to infrequent washings and, instead of being a greasy mess, will start to look incredibly healthy.

"Certainly there is some truth to that," Angela Lamb, a board-certified dermatologist with Mount Sinai Hospital in New York, confirmed to USA Today. However, a lot of the results you will, or will not, experience comes down to what type of hair you're working with. Lamb explained that women with fine hair or those with naturally less oily locks usually have more success when going shampoo-free. Curlier hair, too, can often survive — and thrive — without frequent shampooing.

If you're not sure if your hair could handle weeks without washing, Lamb suggests trying three to four days to start. If your hair feels greasy, you've got the all clear to proceed. If you develop redness or itchy scales on your scalp, though, it's time to suds up. "That's your body trying to tell you that it needs more frequent washing," she added.


Thyroid disease: A checklist of skin, hair, and nail changes

Although your thyroid gland sits deep in your neck, your dermatologist may be the first doctor to notice signs of thyroid disease. That’s because many signs and symptoms of thyroid disease develop on the skin, hair, and nails.

The thyroid gland

The thyroid is a butterfly-shaped gland in your neck that produces hormones, which play a key role in regulating your heartbeat, breathing, and many other functions.

You, too, may also be able to spot thyroid disease, and that’s important. Caught early, treatment can prevent complications. When thyroid disease goes untreated for years, it can lead to a dangerously slow (or fast) heartbeat, an injury that refuses to heal, or unrelenting pain. You may have gained or lost weight for no apparent reason.

To help you find early (and some not-so-early) signs of thyroid disease on your skin, hair, and nails, here’s a checklist.

How many of these signs and symptoms do you have?

☐ Dry, pale, and cool skin
☐ Moist, velvety, and warm skin like a baby’s
☐ Dry skin with deep cracks and scale
☐ Deep, noticeable lines on your palms and soles
☐ Yellowish-orange color on your palms and soles
☐ Doughy and swollen face, especially on your eyelids, lips, and tongue
☐ Widening nose
☐ Slow-healing wounds
☐ Sweating less (or more) than before
☐ Goiter (swelling in the neck)
☐ Protruding eyes
☐ Flushing on your face and red palms
☐ Darker skin in the creases of your palms, on your gums, or elsewhere in your mouth
☐ Rashes, especially in the creases of your skin
☐ Painless lumps and patches of scaly, discolored skin, and the affected skin feels hard and waxy
☐ Reddish spots on the skin that come and go

Protruding eyes

When eyes protrude, it’s often a sign of thyroid disease.

Painless lumps and patches of scaly skin feel hard and waxy

Lumps on discolored skin that feel hard and waxy can be a sign of thyroid disease.

☐ Thinning (or missing) eyebrows on the outer edge
☐ Coarse, dull, dry, and brittle hair that breaks easily
☐ Soft and fine hair with lots of shedding
☐ Thinning hair or balding patches
☐ Growing more slowly (or quickly)
☐ Dry, itchy scalp and dandruff
☐ Less hair on your legs, arms, and other areas

Nails

☐ Thick, dry, and brittle with visible ridges
☐ Soft, shiny, and easily crumble
☐ Growing more slowly (or quickly)
☐ Peel, crumble, or break easily
☐ Lift up
☐ Curved with swollen fingertip and thickening skin above the nail

Curved nails with swollen fingertip

A swollen fingertip, curved nail, and thickening skin above a nail are often signs of thyroid disease.

☐ Itchy skin without a rash
☐ Untreatable and itchy hives

Existing skin disease

You have a higher risk of developing thyroid disease if you have one of the following:

☐ Vitiligo
☐ Hives
☐ Alopecia areata (autoimmune disease that causes hair loss)

When to contact your doctor

If you’ve checked off signs and are not feeling yourself, discuss this with your primary care doctor. These signs don’t necessarily mean that you have thyroid disease. By asking you about your symptoms, your doctor can decide whether you need a blood test to check for thyroid disease.

Have a skin, hair, or nail problem?

Discover the benefits of seeing a dermatologist.

Images
Image 1: Getty Images Images 2, 3, 4: Used with permission of the Journal of the American Academy of Dermatology: J Am Acad Dermatol. 2003 Jun48(6):970-2.

References
Ai J, Leonhardt JM, et al. “Autoimmune thyroid diseases: etiology, pathogenesis, and dermatologic manifestations.” J Am Acad Dermatol. 200348(5):641-59.

Anderson CK, Miller OF. “Triad of exophthalmos, pretibial myxedema, and acropachy in a patient with Graves' disease.” J Am Acad Dermatol. 200348(6):970-2.

Bae JM, Lee JH, et al. “Vitiligo and overt thyroid diseases: A nationwide population-based study in Korea.” J Am Acad Dermatol. 201776(5):871-8.

Callen JP. “Dermatologic manifestations in patients with systemic disease.” In: Bolognia JL, et al. Dermatology. (second edition). Mosby Elsevier, Spain, 2008: 681-2.

Kalus AA, Chien AJ, et al. “Diabetes mellitus and other endocrine diseases.” In Wolff K et al. Fitzpatrick’s Dermatology in General Medicine (seventh edition).” McGraw Hill, China, 2008:1470-4.


The Gene That Causes Gray Hair Has Been Identified

It's well known that graying hair is caused primarily by genetics if your parents went gray, you probably will, too. However, it's only now that scientists have pinpointed exactly which gene may be responsible for this color change.

A study published March 1 in Nature Communications identifies the primary gene responsible for gray hair, and argues that the finding could useful in the field of forensic science. One day, it could also lead to the development of a pill that prevents the salt from overpowering the pepper on your head.

For the study, researchers analyzed the DNA of 6,000 people from Latin America (Brazil, Colombia, Chile, Mexico and Peru) to locate the genes that determine hair color, texture, density and other attributes such as whether a person's hair is straight or has corkscrew curls. The study cohort included people of mixed European, Native American and African origin, giving the researchers a diverse variation of gene pools.

Kaustubh Adhikari, a professor of cell and developmental biology at the University of College London and lead author on the study, says it was already known that the newly identified gene&mdashIRF4&mdash is responsible for light hair color in people of European origin. But this is the first time researchers have shown that it's also tied to gray hair color.

The gene is tasked with regulating and producing melanin, the pigment that gives hair its color. (Melanin is also is responsible for the color of eyes and skin.) Gray hair occurs, in part, when the body starts producing less melanin. When and how much melanin the body produces is determined by genetics.

"As hair grays something happens that causes this gene to produce even lower levels of melanin," says Adhikari. "Now we can ask more specific functional questions." And asking the right questions will then put them one step closer to identifying therapies that delay hair graying.

According to the researchers, there is growing interest in developing therapies that alter the DNA attributes of hair before it actually emerges from the scalp. Up until now, the industry has focused primarily on changing the appearance of hair once it sprouts from the head.

In total, the researchers identified 18 genes that appear to influence the look and feel of hair. They found one gene linked to hair shape. In particular, gene PRSS53 was found to be responsible for hair curliness. This gene is the driver behind the production of a certain enzyme that prompts the hair follicle to produce a certain shape. The study also identified genes related to beard and eyebrow thickness and unibrow.

These findings may be especially useful to the field of forensics and anthropology. For example, in some criminal cases there are biological samples but sometimes insufficient eyewitness information to help investigators identify a suspect. Information on which genes are responsible for certain hair traits might help to unravel a case.


What determines the colour of hair?

Hair colour is produced by cells known as melanocytes, which migrate into the hair bulb as the hair follicles develop in utero. The melanocytes produce pigment that is incorporated into the growing hair fibres to produce hair in a bewildering array of natural shades.

Hair colour depends on the presence and ratios of two groups of melanins: eumelanins (brown and black pigments) and pheomelanins (red and yellow pigments). While variations in the ratio of these pigments can produce an large number of colours and tones, siblings often have strikingly similar hair colour.

Hair colour varies according to body site, with eyelashes being darkest because they contain high levels of eumalanin. Scalp hair is usually lighter than pubic hair, which often has a red tinge, due to the presence of more phaeomelanin pigments. A red tinge is also common in underarm and beard hair, even in people with essentially brown hair on their scalp.

Hormones such as melanocyte-stimulating hormone can darken light hair, as can high levels of oestrogen and progesterone, which are produced in pregnancy. Certain drugs such as those to prevent malaria can lighten hair, while some epilepsy medications can darken it.

Siblings often have strikingly similar hair colour. hans905/Flickr, CC BY-NC-SA

Blond children tend to see their hair darken around the age or seven or eight. The mechanism for this is unknown and probably not related to hormones, as the darkening precedes puberty by a number of years.

New parents often find the first coat of their baby’s hair is darker than expected. It is not until this first hair is shed and replaced, at around eight to 12 months of age, that you get a clear indication of their hair colour.


This Is Why Your Scalp Hurts When Your Hair Is Dirty

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We’ve all tried to extend a blowout past its natural lifespan or relied a little too heavily on dry shampoo during an exceptionally busy week. We know it’s bad for our hair, we know it weighs it down — we know, we know, we know. But why does your scalp hurt when it comes time to wash all that grease out of your hair? Science has the answer.

If you notice an ache or tenderness as you let your tresses down in the shower, it’s because oils your scalp produce naturally build up around your hair shaft. This can lead to the overgrowth of yeast on your scalp (yes, we’re grossed out, too). In an interview with Glamour, Dr. Joshua Zeichner, a New York City-based board-certified dermatologist, explained how this can lead to inflammation.

“In some patients, inflammation may manifest most with an ache,” Zeichner told Glamour.

The inflammation can also cause redness, itching or scaly skin. Though it sounds truly revolting, it doesn’t mean you have a yeast infection on your head. In fact, it’s a totally different kind from the better-known (but equally unpleasant) Candida yeast.

The yeast on your scalp is called Malassezia yeast, and lives on everyone’s bodies, according to Zeichner. When there’s more yeast than normal — for example, when you need to wash your hair — your body becomes more sensitive to it. This is what can cause the aching, itching or discomfort, Dr. Cynthia Bailey, a board certified dermatologist, told Glamour.

Another thing to note: When your hair is oily, you’re more likely to pull it back in a tight ponytail or bun, which can also cause discomfort, Bailey said.

So what’s the solution? Well, wash your hair. Zeichner suggests reducing yeast levels with an anti-fungal shampoo like Nizoral 1% shampoo. You can also use a tar extract-based cleanser like Neutrogena’s T-Gel to reduce inflammation further.

“Remember that while these shampoos may wash hair, they should really be used as scalp treatments,” Zeichner told Glamour.

This means you shouldn’t apply them anywhere but your scalp. Zichner said to lather for the amount of time it takes to sing the alphabet song. Once you rinse the treatment off, you can shampoo your hair as normal.

That should clear up any scalp pain or tenderness, but Bailey warns that you might need to see a dermatologist if symptoms persist.

And if you just cant bring yourself to shower, at least try using one of these cute hair styles for greasy or messy hair:


Gray hair cure? Scientists find root cause of discoloration

Gray hair — one of the classic signs of aging that can lead to a midlife crisis — may some day be a thing of the past, much to the chagrin of hair-dye manufacturers and Corvette salesmen.

A team of European researchers claims to have found not only the root cause of gray hair, but also a treatment for the condition. Additionally, their treatment may help people with vitiligo, a condition that causes the loss of pigment in patches of skin, they say.

It's been known for years that hair turns gray due to a natural buildup of hydrogen peroxide in hair follicles, which causes oxidative stress and graying. (Hydrogen peroxide solutions have been used for years as a cheap and easy way to "go blonde.")

In younger people, an enzyme called catalase breaks down hydrogen peroxide into water and oxygen. But lower levels of this enzyme, combined with lower levels of enzymes called MSR A and B that repair hydrogen peroxide damage, cause hair to turn gray as we age.

The researchers, whose findings are published in the experimental-biology publication FASEB Journal, analyzed 2,411 people with vitiligo.

By looking at people with two different kinds of vitiligo — strictly segmental vitiligo (SSV) and non-segmental vitiligo (NSV) — they discovered that both kinds resulted from oxidative stress.

And by applying a topical treatment, a substance called PC-KUS, the researchers successfully treated the discolored skin and eyelashes of people with vitiligo.

Though gray hair isn't always a welcome sign of aging, there's some evidence that suggests it can be an indicator of good health.

Researchers in 2012 found that wild boars with significant graying hair "were actually those in prime condition and with the lowest levels of oxidative damage," researcher Ismael Galván of the Museo Nacional de Ciencias Naturales in Spain said in a statement.

"Far from being a sign of age-related decline, hair graying seems to indicate good condition in wild boars," Galván said.

Nonetheless, many people will go to extreme lengths to hide any hint of aging, including gray hair.

"For generations, numerous remedies have been concocted to hide gray hair," Dr. Gerald Weissmann, editor-in-chief of FASEB Journal, said in a statement. "But now, for the first time, an actual treatment that gets to the root of the problem has been developed."

The treatment will be welcome news to people with severe or unsightly cases of vitiligo. "This condition, while technically cosmetic, can have serious socio-emotional effects," Weissmann said. "Developing an effective treatment … has the potential to radically improve many people's lives."