How Many Arachnids Live in Your Eyelashes?

Pretty much every human has thousands of microscopic mites living in the hair follicles on their face, feeding off of the dead skin cells and oils there. Learn why you probably shouldn't worry about Demodex mites in today's episode of BrainStuff, based on this article: https://health.howstuffworks.com/human-body/systems/eye/are-there-really-arachnids-living-in-my-eyelashes.htm

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Episode Transcript

Speaker 1 (00:01):
Welcome to Brainstuff, a production of iHeartRadio. Hey, brain Stuff,
Lauren Boglebaum. Here it probably sounds more like a scene
from a horror movie than a scientific reality, but human
eyelashes are in fact home to iraknids, veritable oodles of them.

(00:22):
Each individual hair follicle on your eyelids can contain as
many as twenty five of the creatures. When you consider
that we humans have up to eighty lashes on our
lower lids and one hundred and sixty on our upper lids,
that's possibly some six thousand tiny iracanids living on our
faces at any given time. It's believed that almost every human,

(00:45):
no matter how well groomed, has them. Babies are born
without mites, but they pick them up almost immediately from
the people around them. Since these tiny beings make themselves
at home on our faces today, let's get to know
them a little little better. Many of us think of
spiders when we hear the word arachnid, but there are

(01:05):
other types of these eight legged invertebrates, including scorpions, ticks,
and mites. It's that last category that resides around our eyelashes.
More specifically, they are mites in the Demodex genus the
species Demodex filiculorum and Demodex brevis. Unlike many other mites

(01:25):
that have rounded or bulb shaped bodies, such as dust mites,
for example, Demodex mites have an unusual elongated body shape,
with their four pairs of short legs coming off of
a segment behind their mouth, and then a long abdominal
section trailing after that. The picture a semi transparent caterpillar
with only eight stubby legs right at the front. Defiliculorum

(01:49):
is a bit longer and deebrevis a bit shorter, hence
the name. The reason you may not have known that
these follicle dwellers exist is because they're microscopic. They're less
than a third of a millimeter long, which is around
the width of a human hair, and smaller than some
single celled organisms. Most could fit inside a droplet of mist.

(02:11):
They're small enough that they can wander down into your
hair follicles and oil glands, and indeed that's where they
usually hang out during the day. Because they're not fond
of bright light, these mites live on your lashes so
that they can eat the oils and skin cells they
find there. Defolliculorum eats skin cells, while de Brevis prefers

(02:33):
sebum made by oil glands on the lash line to
help keep your eyes protected and moisturized. These mites can
also reside on small hairs throughout the face, including the nose, cheeks,
and ears, on the neck and chest, and sometimes elsewhere
on the body, so that six thousand guestimate above may
actually be on the low end. Neminex mites live short

(02:56):
lives of about two to four weeks. Their mating habits
can take in a speed dating quality. The female stays
on her lash and the males hop from follicled follicle
looking for a partner. The mites can also jump onto
another person's face, so if you spend time snuggling with
a loved one, you're probably providing new mating opportunities for

(03:17):
one another's eyelash mites. When they die, they decompose in
your hair, follicles or sebaceous glands. We're not alone in
being hosts to follicular mites. There are over one hundred
different species that make their home around the hairs of
mammals and marsupials, from bats to dogs to armadillos. Most
of them are harmless or rarely our demodex mites can

(03:41):
multiply out of control, though, and cause irritation to our
skin our eyes in the form of demodicosis, a condition
that can appear as tiny pustules or scales on the
skin of your face, along with itching or burning. They
can also cause a type of blepharitis, which is eye
irritation that comes with swollen or scaily eyelids and lash
loss or crustiness. Both conditions are treated with lotions, washes,

(04:06):
or eye drops, with a pesticide to kill the mites,
other ingredients to help remove excess oil and dead skin
that they feed on, and something to help soothe the irritation.
My overgrowth is usually a result of your immune system
being compromised or suppressed. If that applies to your loved
one and you see these symptoms, talk to a health
care provider about it. There is some evidence that, for

(04:30):
reasons we don't understand, demodex mites might have a role
in the development of other skin conditions like rseatia and acne.
Scientists are looking into it. Generally, though these microscopic facerachnids
are considered harmless, they might even be helpful. Some researchers
think that they may help prevent clogs in our facial

(04:53):
pores and may even protect us from the pathogenic bacteria
that can cause staff and strep infections. Also, there's evidence
that they're evolving from being parasitic to humans to being
symbiotic with us. In twenty twenty two, a team of
researchers published their findings from having sequenced the genome of Defoliculorum.

(05:14):
They learned a lot during their course of study. Due
to the mite's isolated lives with no competition from other
mites with different genes, these creatures have become extremely simple organisms.
Their tiny legs are powered by just three single cell muscles.
They also cannot make their own melatonin, which regulates when

(05:35):
animals sleep and wait, but they can use the melatonin
created by us they're human hosts to power their night
long mating sessions. The average human will be host to
over one thousand generations of mites in their lifetime. We
really do contain multitudes. Today's episode is based on the

(05:59):
article so are there really arachnids living in my eyelashes?
On HowStuffWorks dot com, written by Jennifer Sellers Brain Stuff
is production of iHeartRadio in partnership with HowStuffWorks dot Com
and is produced by Tyler Klain. Four more podcasts from
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