Name: ニキビを消すには？ (How Do You Get Rid of Acne?)
Uploaded: 2021-01-14T07:48:11.000Z
Duration: 8 min 53 s
Description: VoiceTubeの動画で発音を聞きながら英語表現を覚えよう！学べる英語：

Imagine waking up the morning of prom, or
your wedding day, or a big job interview…

and sure enough, you look in the mirror to
find your forehead is covered in zits!

Acne, or acne vulgaris, is the most common
skin disease in humans.

It affects about 80% of people at some point
in their lives.

Most people get acne between the ages of 11
and 30, but sometimes older people continue

Acne happens when follicles and pores become
clogged with dead skin cells and oils.

But by studying how acne forms, doctors have
developed ways to prevent and treat it.

It all starts with your skin: a complex organ
made up of two layers and lots of nerves,

Your skin cells regenerate about once a month,
so you constantly have dead skin cells sloughing

off, and new skin cells rising to the surface.

This whole skin-replacement thing isn't
much of a problem, on its own.

But lots of these dead skin cells come out
through your pores.

Skin pores are essentially just openings for
tiny hairs.

Hair follicles, the root ends of the hairs,
are embedded in your skin and surrounded by

clusters of sebaceous glands, special glands
that produce sebum.

Sebum is that oily, waxy stuff that comes
out of your pores.

It helps keep your skin waterproof and moisturized:
it keeps excess water out of your body, and

it keeps water already inside you from getting
out through your skin.

But things can go very wrong if your sebum
production gets out of whack.

When your body doesn't produce enough sebum,
your skin can dry out, making you more susceptible

But if your body produces too much sebum,
it can build up inside your pores, trap dead

Increased sebum production is one of the major
factors involved in the development of acne.

Increased keratin production is another one.

Keratin is a protein produced by your hair
follicles.

It gives structure to each strand of hair,
as well as the top layer of your skin.

But when the hair follicles produce too much
keratin, the extra protein binds together

dead skin cells, so they can't just shed
out of the pore like they normally would.

You end up with a blockage that then traps
more dead skin cells, plus sebum.

Once the pore is officially clogged, it becomes
a breeding ground for colonies of bacteria

That's a species of commensal bacteria,
which basically means it's friendly.

It naturally lives on your skin, and it's
not harmful … most of the time.

The commensal bacteria that make up your microbiome
probably even help prevent other, more harmful

So having colonies of Propionibacterium acnes
living on you isn't a bad thing.

You want them there — as long as they stay
on the surface of your skin.

When the bacteria find their way deep into
skin pores where they don't belong, that's

When you get an infection, your immune system
responds by increasing blood flow to the area

and sending extra immune cells and enzymes
to fight off the infection.

Different combinations of symptoms cause different
kinds of acne, with names you've probably

heard before:Blackheads, whiteheads, pimples,
pustules … technically, they all mean different

The scientific term for a clogged pore is
a comedo, which actually used to mean a parasitic

People started using the term to refer to
a clogged pore because the stuff that comes

out when you squeeze it looks kind of like
a worm.

When the main symptom is just that the pore
is clogged, without much inflammation, that's

Blackheads are what it's called when the
comedo is open.

The trapped sebum and dead skin cells become
oxidized, which turns the surface of the clogged

material into a dark color, kind of like how
silver tarnishes.

When the comedo closes, skin cells grow over
the top of the plug and stop this oxidation

from happening, so the whitish color of the
sebum shows through.

When there's a comedo plus an infection
that causes inflammation, that's a different

The typical reddish bumpy kind are more specifically
called papules.

If the inflammation gets really bad, sometimes
the bumps start leaking fluid or bacteria-filled

Those kind are categorized as pustules, and
they're usually a much brighter red, or

The most severe kind of acne is generally
called cystic acne.

That's when the infection takes root in
the deepest layers of the skin.

Sometimes the infection causes more solid
bumps to form, called nodules.

And sometimes the infection causes pus-filled
bumps, called cysts.

What makes healthy pores become clogged, infected,
and sometimes ooze-y?

Again, there are a few different factors involved.

Genetics seem to be important, for one thing.

So if your parents had acne, you're more
likely to have it too.

Hormones also have a huge influence on acne
— specifically, androgen hormones, like

testosterone, which influence the development
of both the male and female reproductive systems.

Which explains why acne is so much more of
a problem during puberty.

Androgen hormones are linked to sebum production.

So during puberty, when the hormones are highly
active, there's an increase in sebum production.

Increased stress has been thought to increase
hormone production, as well.

So if you find yourself breaking out the day
before a big test, that's probably why.

When you're stressed, you produce more hormones,
which then increases your sebum production.

Since sebum is an oil, a lot of people say
that greasy foods will cause acne.

Sometimes you'll also hear that dairy makes
it worse, or even more specific foods, like

But the truth is, scientists aren't really
sure how or whether diet and acne are connected.

There have been lots of studies investigating
this, and some do suggest a possible link.

We need more comprehensive, controlled trials
with plenty of subjects before we can come

Doctors do acknowledge that there's anecdotal
evidence, and they say that if changing your

diet has helped with your acne, then it makes
sense for you to stick with it.

There just isn't enough evidence to support
the idea that diet has a role in acne in general.