Face mites, tiny creatures living on the skin of our faces, are not rare, research suggests; in fact, they're absolutely ubiquitous.
No matter how often or how thoroughly you wash your face -- and never mind disinfectants or exfoliating scrubs -- the pores of your facial skin are home to organisms that have evolved to live there, they researchers say.
"Within our samples, 100 percent of people over 18 years of age appear to host at least one Demodex species, suggesting that Demodex mites may be universal associates of adult humans," they report in the journal PLOS ONE.
Of the 48,000 mite species known to science, two have been detected living on human faces, buried head-down in our hair follicles, living off the skin oils our faces secrete.
The two species, Demodex folliculorum and Demodex brevis, have been found in every human ethnic group.
To test for the presence, researchers at North Carolina State University developed a DNA test.
The mites possess the peculiar property of excreting no waste products during their lives; instead, a lifetime's worth of mite poop is released only when they die.
It contains DNA that can reveal their presence even if the mites are hidden from any other means of detection.
In the study, 100 percent of the adults showed mite DNA on their facial skin, suggesting having face mites is a universal condition.
"The first time I found one on my face I didn't sleep for four nights," study co-author Megan Thoemmes says. "They're actually pretty cute. With their eight little legs, they look like they're almost swimming through the oil. It's like having friends with you all the time. Realizing that everyone has them and they're likely not causing any problems, it's pretty reassuring."
One of the study findings is that genetically the two species of face mites are not close relatives, suggesting the possibility of their being acquired from different hosts in humanity's evolutionary past. D. brevis is more closely related to dog mites the D. folliculorum, the researchers say.
Mites are ubiquitous on more than just humans, it turns out. The tiny arachnids -- relatives of ticks and spiders -- have been found living on every species of mammal on Earth.
Although for the most part their lives on the skin of their hosts is an example of benign coexistence, they can cause mange of some of our furry mammal friends, and human can sometimes suffer from skin ailment like rosacea caused by the mites.
The mites have probably been with us for a long time; when early humans moved out of Africa to spread around the globe, they likely carried mites with them, experts say, making man and mite old friends, at least from an evolutionary perspective.
Read more: Meet Demodex, tiny mites on your face
