Researchers have identified tiny, 8-legged mites found living in the pores of human faces and feeding on the skin oil produced by sebaceous glands.
Michelle Trautwein, an entomologist at the California Academy of Sciences in San Francisco, led the study on microscopic creatures known as Demodex. These mites are only 0.3 millimeters long, making them too small to be seen by the naked eye.
While the Demodex mites were named after the Greek words for "fat" and "boring worm," they are not necessarily worms. These creatures are arachnids, so they are more related to spiders and ticks.
Relationship Of Face Mites With Humans
To find out what role the Demodex mites play on their human hosts, Trautwein examined the arachnids' DNA. She found that each part of the world has a different set of face mites.
The researcher believes the tiny creatures may help tell a story about people's ancestry, as well as the history of ancient humans and their migration.
Trautwein collected Demodex samples from the faces of more than 2,000 people. These include tourists from different parts of the world who visited the Academy of Sciences in California.
She and her team used small spoons to scrape the mites from the greasier parts of people's faces. They then subjected the tiny creatures to DNA testing.
The team discovered DNA traces of the Demodex face mites on all of the participants.
The idea of having microscopic arachnids on people's faces may not be thrilling for many, but Trautwein said there are some who are curious despite being repulsed by the creatures.
How Demodex Mites Get To Human Faces
There are two known species of face mites found on people's skin: the Demodex folliculorum and the Demodex brevis. These creatures often find their way to the shaft of hair follicles, spending most of their days nestled up against them.
Demodex mites live off of the skin's sebum. This greasy oil is normally used to waterproof the skin and keep it from drying out. Sebaceous glands empty sebum into hair follicles, allowing them to coat both the shaft and the face mites.
The eyes, nose, and mouth are the areas where face mites can often be found in large numbers because of the high amount of grease they typically produce.
The researchers said Demodex spend most of their two-week lifespan staying inside the skin's pores. However, they often crawl out of their hiding places to mate with other face mites. Once they are ready to lay their eggs, they make it back to pores.
People find it difficult to get rid of these face mites, no matter how much they try to scrub off because these creatures live inside the pores. This also makes it next to impossible to eliminate all of the Demodex from the body.
Trautwein described how she used glue to remove the tiny creatures from the subjects' skin. She put some of the adhesives on a glass microscope slide then placed it on people's foreheads. This allows her to get some hair follicles that often have face mites with them.
"It can be pretty addictive and exciting," Trautwein said. "It's sort of a meditative process of looking through this microforest of follicles and hairs and looking for just the right potential movement or shape."
How Face Mites Can Affect Human Health
The body's immune system helps make sure that the population of Demodex mites does not get out of hand. However, there are some people who still get bothered by the existence of the tiny creatures on their skin.
In some cases, people who have too many face mites go on to develop a skin condition known as demodicosis. Kanade Shinkai, a skin expert from the University of California, San Francisco, explained how the illness affects patients' health.
"There is a very particular look to people suffering from demodicosis. We call it the Demodex frost," Shinkai said. "It's sort of a white sheen on the skin. And if you look really closely, you can see [it] coming out of every pore. If you scrape those pores, you can see it frothing with little Demodex face mites."
Demodicosis is considered as a relatively rare medical condition and mostly associated with people who have declining immune systems such as those undergoing immunosuppressive treatment following surgery or chemotherapy.
The illness can also be found in patients diagnosed with AIDS or other immunodeficiency diseases.