You can’t see them, but they’re there. They are microscopic mites, eight-legged creatures rather like spiders. Almost every human being has them. They spend their entire lives on our faces, where they eat, mate and finally die. Before you start buying extra-strong facewash, you should know that these microscopic lodgers probably aren’t a serious problem. They may well be almost entirely harmless. What’s more, because they are so common they could help reveal our history in unparalleled detail.
There are two species of mite that live on your face: Demodex folliculorum and D. brevis. They are arthropods, the group that includes jointed-legged animals such as insects and crabs. Being mites, their closest relatives are spiders and ticks. The two species live in slightly different places. D. folliculorumresides in pores and hair follicles, while D. brevis prefers to settle deeper, in your oily sebaceous glands. Compared with other parts of your body, your face has larger pores and more numerous sebaceous glands, which may explain why the mites tend to live there. But they have also been found elsewhere, including the genital area and on breasts. Scientists have known that humans carry face mites for a long time. D. folliculorum was spotted in human earwax in France in 1842.
In 2014, it became clear just how ubiquitous they are. Megan Thoemmes of North Carolina State University in Raleigh and her colleagues found, as had previous studies, that about 14% of people had visible mites. But they also found Demodex DNA on every single face they tested.
That suggests we all have them, and probably in quite large numbers. “It’s hard to speculate or quantify but a low population would be maybe in the hundreds,” says Thoemmes. “A high mite population would be thousands.” Put another way, you may have around two mites per eyelash. The populations may well vary from person to person, so you might have many more than your neighbour or far fewer. You may also have more mites on one side of your face than the other. Yet it’s not clear what the mites are getting from us. For starters, we’re not sure what they eat.
Shahmshad Ahmed Khan