Face mites: They really grow on you: Shots
It might give you scary creepy-crawlies, but you're almost certain to have tiny mites that live right in the pores of your face.
They are known as Demodex or eyelash mites, and almost every adult human lives on them.
The mostly transparent creatures are too small to be seen with the naked eye. At a length of about 0.3 millimeters, about five adult facial mushroom mites would be needed, laid end-to-end to extend over the top of a pin.
"They look like little dull worms," says Michelle Trautwein, an entomologist at The California Academy of Sciences in San Francisco.
Demodex Face mites have their name from the Greek words for "fat" and "boring worm", but they are no real worms at all. In fact, they are arachnids related to ticks and, even further away, spiders.
Trautwein examines our relationship with these microscopic blind people based on their DNA. Their findings suggest that people in different parts of the world have different facial mites. "They tell a story of their own descent and also a history of older human history and migration," she says.
But before she could tell this story, she had to find the mites.
"We use a small spoon and scratch it over the greasy areas on someone's face, which is not as bad as it sounds," says Trautwein.
Once the samples have been collected, she takes them back to the lab to look at the genetics.
Trautwein has tested more than 2,000 people, including tourists from all over the world, who have found their way to the California Academy of Sciences. And she has found DNA evidence for facial mites on each and every one of them.
"Nobody is thrilled with the initial idea that they have arachnids on their faces," says Trautwein. "But people are often curious – even in their dislike."
But how could these creatures live on so many people and yet go unnoticed?
Our skin is mostly covered by a thin layer of peach fluff called Vellus hair with a few notable exceptions such as the palms and feet. The shaft of each tiny hair grows out of its own follicle.
Face Mites – Demodex folliculorum and Demodex brevis – spend their days face down in your hair follicles, which cling to the hair shaft and are not visible from there.  Face mite "/>
You eat sebum, the greasy oil that makes your skin protect and protect against dehydration. The sebum is produced in sebaceous glands, which open into the hair follicles and cover both the hair shaft and the facial mite.
Because of this, the fattest parts of the body like eyes, nose and mouth are likely to have higher levels of mites than in other areas.
The mites live about two weeks. They spend most of their time in their pores, but as people sleep, they crawl on the surface of the skin to mate, then go back to lay their eggs.
Living in your pores, you can not wash them off. Basically, it is impossible to get rid of all facial mites.
How does Trautwein find and investigate a specific mite? With glue.
"I actually applied glue to a glass slide and stuck it on a person's forehead," she says. "Then I take it off slowly and I search for mites in a microscope, which are stuck in the follicles, which stick out from the thin layer of skin that has peeled away."
"It can be quite addictive and exciting," she adds. "It's a kind of meditative process to look through this microflora of follicles and hair and look for just the right possible movement or shape."
It seems that our immune system is able to keep their numbers at bay, but some people may experience mite problems.
"When you tell patients that they have facial mites, they are freaking out first," says Kanade Shinkai, dermatologist at the University of California, San Francisco.
Since then, facial mites live in your pores, you can not wash them off. But for most people, they are harmless.
Josh Cassidy / KQED
Josh Cassidy / KQED
Since facial mites live in your pores, you can not wash them off. But for most people, they are harmless.
Josh Cassidy / KQED
Shinkai occasionally treats patients with facial mite congestion, leading to demodicosis.
"Demodicosis sufferers are given special attention, we call them Demodex. Frost," she says. "It's a kind of white shimmer on the skin, and if you look closely, you can see that [it] comes out of every pore, and if you scrape those pores, you can see it's foaming with little Demodex Face mites. "
The condition is relatively rare and is often associated with a decline in the immune system, such as the use of immunosuppressants after transplant surgery, chemotherapy or immunodeficiency diseases such as AIDS.
Demodicosis can also be triggered by a local suppression of the immune system, for example by the application of an itch-relieving hydrocortisone cream on the face.
It usually sets in quickly. "Patients describe this explosive development of pustules similar to whiteheads on their face almost universally, it's really dramatic," says Shinkai. "And what's really dramatic is that they are doing well the day before and then developing it overnight."
For the vast majority of people, facial mites are not a cause for concern. While some studies have found loose links between Demodex and diseases such as rosacea, the evidence has shown no strong association.
"What's really confusing is that if you go into your office and scratch everyone's face, you'd probably find Demodex with everyone," says Shinkai. "And people with a low burden of Demodex can have no or very serious illnesses and vice versa."
Trautwein regards facial mites as a source of concern rather than anxiety.
"They are not dangerous in the broadest sense, because we all have them and most of us live pretty well with them," says Trautwein. "We largely divide them within family units, and it seems that you are likely to be colonized shortly after birth, most likely by your mother, traditionally in human history." something about your geographical origin – from which part of the world your ancestors came.
"Face mites are definitely the species we humans have the closest connection with, although most of us do not know about them or we've never seen one in our lives," she says. "We still have this very old and intimate relationship, and it seems clear that we had this face mite species for the entire story, so they are as old as our species, as old as Homo sapiens . "