Demodex mites are tiny eight-legged parasites that mostly live in hair follicles and oil glands on your face, neck, or chest. As alarming as this may sound, they’re generally harmless. In fact, they can even help your skin by removing dead skin cells. But if you get too many of them, they can cause an infection that irritates your skin.
They’re very common. Scientists estimate that from 23%-100% of healthy adults have them. But you likely won’t know you have them unless your skin acts up. You can’t see them without a microscope.
Even if you can scrub your face, the mites probably won’t come off. But there are treatments that can kill them if they start to cause problems.
How Demodex Mites Survive on Your Body
Male and female mites usually mate inside a follicle opening. They lay eggs inside your hair follicles and oil glands. Larvae hatch within 3-4 days and reach adulthood after 7 days.
The mites live about 2 weeks. They usually come out at night to feast on dead skin cells before retreating to their hiding spots to lay eggs. When they die, they break down inside your hair follicles and sebaceous glands.
Demodex mites are contagious. They move from person to person by contact with hair, eyebrows, or oil glands on the skin.
Types of Demodex Mites
Two types of Demodex mites live on humans: Demodex folliculorum (D. folliculorum) and Demodex brevis (D. brevis). D. folliculorum mites are around 0.3-0.4 millimeters long, while D. brevis mites are slightly smaller at 0.15-0.2 mm.
Both types have elongated, semi-transparent bodies made up of two fused segments, one of which has eight legs attached. Scales cover their bodies, helping them attach to your hair follicles. Each has mouthparts designed to consume skin cells, oil, and hormones in your hair follicles and oil glands.
Demodex folliculorum. This is the most common type of demodex mite. They tend to stay in the facial area, including your nose, cheeks, chin, eyelashes, eyebrows, and scalp. They might also be found on your neck and ears. They like to get inside the upper part of a hair follicle and survive on skin cells and oil.
Demodex brevis. While D. brevis isn’t as common as D. folliculorum, they affect a larger area of your body. They can affect your face and eyes but tend to migrate to your chest and neck area. They prefer to go deep into the oil glands there and feed on the cells.
Symptoms
Symptoms of Demodex folliculorum infection
Some common symptoms of D. folliculorum infection are:
- Rough skin
- Scaly, flaky, or itchy skin
- Redness or rashes
- Skin sensitivity
- Burning
- Eczema
- Inflamed papules and pustules that resemble whiteheads
If your eyes are affected, you could notice:
- Blepharitis (eyelid irritation)
- Itchiness
- Loss of eyelashes
Symptoms of Demodex brevis infection
D. brevis symptoms are similar to those of D. folliculorum. But unlike with D. folliculorum, you may notice them on your neck or chest area.
Diagnosis
Diagnosis of Demodex folliculorum infection
You can’t tell you have D. folliculorum unless you develop symptoms. To diagnose it, your doctor will scrape your skin to get a sample. Then they’ll look at it under a microscope.
Diagnosis of Demodex brevis infection
Your doctor diagnoses D. brevis the same way they do D. folliculorum -- by looking at your skin cells under a microscope.
How Demodex Mites Impact Your Health
Small numbers of Demodex mites can be beneficial because they remove dead skin cells and extra oil on your skin. As long as the amount of mites on your skin stays under control, you are unlikely to experience any problems.
But sometimes, people end up with too many mites burrowing into their skin, leading to demodicosis -- the infection that causes skin inflammation.
People between ages 20-30 may be more vulnerable to demodicosis, as can older people and children under 5. You may also be prone to this rare condition if you’re on immunosuppressive drugs or have an immune-related disease like HIV/AIDS or liver disease.
Demodex mite complications
Some common conditions that have been linked to infestations of Demodex mites include:
Blepharitis. This inflammation of the eyelids is caused by a blockage in the oil glands in that area, usually at the base of your eyelashes. Demodex mites are often the reason people over 60 develop blepharitis.
Signs of blepharitis include:
- Redness
- Tearing
- Burning or stinging sensation in your eyes
- White flakes in your eyelashes
- Feeling like something is in your eye
- Sensitivity to light
- Brittle eyelashes
- Loss of eyelashes
- Blurred vision at times
Rosacea. This skin condition causes redness, mostly on the face. But it can also affect your neck, chest, ears, and scalp. Researchers have found larger numbers of Demodex mites on people’s skin in the same areas affected by rosacea.
It’s not clear whether rosacea causes a Demodex mite infestation or whether rosacea is a result of the mites. Some experts think that having too many Demodex mites on the skin can trigger a reaction and lead to rosacea. Another theory is that bacteria tied to the parasites causes rosacea.
Signs of rosacea include:
- Lasting redness
- Thickened skin
- Blushing or flushing
- Eye irritation
- Bumps and pimples
- Visible blood vessels
- Swelling
- Dryness
- Stinging or burning
Demodex Mite Treatment
If you have lasting skin irritation, a rosacea breakout, or a blepharitis issue that doesn’t go away, see a doctor.
The most commonly used treatment for demodicosis is a medication you apply to your skin called metronidazole. Other treatments include:
- Permethrin
- Benzyl benzoate
- Crotamiton
- Lindane
- Sulfur products
- Ivermectin
- Salicylic acid
- Selenium sulfide
- Pulsed dye laser treatments
If your doctor thinks mites caused your blepharitis, they’ll advise cleaning your eye area daily with warm water. Warm compresses can help relieve swelling while they clean your lashes and eyelids.
Your doctor may exfoliate your eyelids (remove dead skin from them) to provide relief. Medicated ointments can help prevent the spread of Demodex mites from your eyelashes.
Some people use tea tree oil as a home remedy for Demodex, but researchers aren’t sure how well it works. One study found it draws the mites out of your skin, which could make it easier for treatments to work. But tea tree oil can irritate your eyes.
Demodex Mite Prevention
These parasites live harmlessly on most people’s skin. But if you want to reduce how many you have even if you don’t have symptoms of an infection, there are steps you can take:
- Keep your skin clean and wash your face twice a day.
- Avoid greasy skin products that may add extra oil or clog pores.
- Exfoliate your skin regularly.
