You probably don't think of your face as a homestead for bugs, but it's true. Human skin is literally crawling with microscopic insects called mites and these critters have a fondness for hair follicles, especially the ones that belong to eyelashes and nostril hair. Normally, these super-tiny critters don't cause problems for their human hosts but in rare cases, they can cause eye infections.
We've known about face mites since the early 1840s, thanks to their near-simultaneous discovery by two German scientists. In 1841, Frederick Henle found tiny parasites living in earwax but he wasn't sure how to classify them within the animal kingdom. He said as much in a letter to German physician Gustav Simon, who discovered the same parasites year later while studying facial pimples. Demodex folliculorum had arrived.
More than a century later in 1963, a Russian scientist named L. Kh. Akbulatova noticed that some face mites were a bit smaller than the others. He considered the shorter mites a subspecies and referred to them as Demodex brevis. Subsequent study determined that the mite was actually a distinct species, with a unique morphology that differentiated it from the larger Demodex folliculorum.
All About Mites
There are more than 60 species of parasitic mite, but only two, Demodex folliculorum and Demodex brevis, like to live on human beings. Both can be found on the face, as well as the chest, back, groin, and buttocks. The Demodex brevis, sometimes called the face mite, prefers to live near sebaceous glands, which produce oil the keep the skin and hair moist. (These glands also cause pimples and acne when they become clogged or infected.) The eyelash mite, Demodex folliculorum, prefers living on the hair follicle itself.
Research shows that the older you are, the more face mites you have tucked away in your facial follicles. Newborn babies are mite-free, but by age 60, virtually all humans are infested with face mites. Face mites are believed to spread from person to person via close contact and a healthy human adult is colonized by 1,000 to 2,000 follicle mites at any given time, without ill effects.
Facial mites have eight stubby legs and long, thin heads and bodies that allow them to move in and out of narrow hair follicles with ease. Face mites are tiny, measuring a mere fraction of a millimeter long. They spend their lives head-down in the follicle, gripping onto the hair or lash tightly with their feet.
Follicle mites (Demodex folliculorum) typically live in groups, with a few mites sharing a follicle. The smaller face mites (Demodex brevis) seem to be loners and generally only one will occupy a given follicle. Both species feed on the secretions of oil glands and Demodex folliculorum is thought to feed on dead skin cells as well.
Occasionally, a face mite may need a change of scenery. Face mites are photophobic, so they wait until the sun goes down and the lights are off before backing slowly out of their follicle and making the arduous journey (moving at a rate of about one centimeter per hour) to a new follicle.
There are still some things that researchers don't know about facial mites, especially when it comes to their reproductive lives. Scientists believe that facial mites may only lay one egg at a time because each egg can be up to half the size of its parent. The female deposits her eggs inside the hair follicle and they hatch in about three days. Within the span of a week, the mite progresses through its nymphal stages and reaches adulthood. Mites live about 14 days.
The link between facial mites and health problems is not well understood, however, scientists say they do not normally pose any issues for people. The most common disorder, called demodicosis, is caused by an overabundance of mites on the skin and hair follicles. Symptoms include itchy, red, or burning eyes; inflammation around the eyelid; and crusty discharge around the eye. Seek medical treatment if you have any of these symptoms, which can also indicate other health issues besides mites.
In some instances, your doctor may recommend a prescription or over-the-counter antibiotic treatment. Some people also recommend cleaning the eyelashes with tea tree or lavender oil and washing the face with baby shampoo to remove mites. You may also want to consider discontinuing the use of cosmetics-especially mascara and eyeliner-until your skin is clear.
People suffering from rosacea and dermatitis tend to have a much higher number of face mites on their skin than persons with clear skin. However, scientists say there's no clear correlation. The mites may cause the skin to break out, or the infection may attract abnormally large mite populations. Large face mite populations have also been found on people suffering from other dermatological disorders, such as alopecia (hair loss), madarosis (loss of eyebrows), and infections of hair and oil glands on the head and face. These are fairly uncommon, and the link between them and mites is still being studied.
- Hassan, Iffat, and Rather, Parvaiz Anwar. "Human ." Indian Journal of Dermatology. January-February, 2014. Demodex Mite: The Versatile Mite of Dermatological Importance
- Jones, Lucy. "These Microscopic Mites Live on Your Face." BBC.com. May 8, 2015.
- Knutson, Roger M. "Furtive Fauna: A Field Guide to the Creatures Who Live on You." Viking Penguin, 1992.
- Berenbaum, May R. "Bugs in the System: Insects and Their Impact on Human Lives." Addison-Wesley, 1995.
- Rajan, T.V. "Textbook of Medical Parasitology." BI Publications Pvt Ltd, 2008.
- Gutiérrez, Yezid. "Diagnostic Pathology of Parasitic Infections: With Clinical Correlations." Oxford University Press, 2000.