Eyelid mites, also known as Demodex, are tiny parasitic mites that live in or near hair follicles of mammals. Two species live on humans: Demodex folliculorum and Demodex brevis. These harmless mites are found on the skin of most adults.
What Are Eyelid Mites?
Eyelid mites are members of the Demodex genus, a type of arachnid. They are distantly related to spiders and ticks. There are over 100 species of Demodex mites identified, but only two live on humans:
- Demodex folliculorum – Lives in the hair follicles
- Demodex brevis – Lives deep in the sebaceous glands connected to the hair follicles
These two microscopic mites are invisible to the naked eye. They feed on skin cells and oils inside the hair follicles. Since they don’t bite or burrow into the skin, they typically don’t cause itching or irritation.
What Does Demodex Look Like?
Demodex mites have a tiny, elongated body only 0.3-0.4 mm long. D. folliculorum is longer than D. brevis:
- D. folliculorum – 0.35-0.4 mm long
- D. brevis – 0.15-0.2 mm long
These mites have eight short legs for grasping hair follicles. They lack eyes and respiratory organs. A segmented body allows some flexibility to squeeze into follicles. The mite’s body is covered with scales for gripping surfaces. The mite attaches itself to the follicle with hook-like mouthparts.
Demodex Folliculorum
Also called the longer eyelash mite, D. folliculorum lives solitary in the hair follicle. It is shaped like a long cigar with eight stubby legs:
- Cigar-shaped body
- 0.35-0.4 mm long
- Eight short, stump-like legs
- Mouthparts shaped like hooks for attachment
- No eyes or respiratory organs
- Whitish-transparent color
Demodex Brevis
The shorter eyelash mite (D. brevis) is stouter with a partially overlapping body:
- Overlapping body sections
- 0.15-0.2 mm long
- Eight short legs
- No eyes or respiratory organs
- Sphere-shaped mouthparts for attachment
- Whitish-transparent hue
Where Are Eyelid Mites Located?
Demodex mites live inside the hair follicles, specifically in the following areas:
- Eyelashes – D. folliculorum thrives along the lash line.
- Eyebrows – D. folliculorum and D. brevis inhabit brow hairs.
- Nose – In nose pores and follicles.
- Cheeks – In hair follicles on the face.
- Forehead – Around follicles above the eyes.
The mites emerge from follicles at night to mate and deposit eggs. Then they crawl back into the pores to avoid light.
What Does a Demodex Infestation Look Like?
Nearly 100% of adults have eyelash mites living on them. Low levels don’t cause issues or symptoms. But if the mite population rapidly grows, it can lead to an infestation called demodicosis. An overgrowth of Demodex mites may cause:
- Redness and inflammation of the eyelid margins
- Greasy scales or crusting on the lashes
- Missing lashes (madarosis)
- Red, itchy, sore eyes
- Blurry vision
- Eyelash mats or clumping
Some people are more prone to Demodex overgrowth, including those with weakened immune systems and chronic skin conditions like rosacea. Suppressing the immune system with medications can also trigger an infestation.
What Does Demodex Look Like Under a Microscope?
Demodex mites are invisible to the naked eye. To view them, doctors scrape skin cells from around the eyes and eyebrows. Then they examine the sample under a microscope to look for two hallmark signs of Demodex mites:
- The mite body – The microscope reveals the elongated, segmented body and short stubby legs of Demodex.
- Eggs – Microscope images also show the oval-shaped mite eggs attached to hairs.
Here is what Demodex folliculorum and brevis look like under the microscope:
| Demodex Species | Microscope Image | Description |
|---|---|---|
| D. folliculorum | Cigar-shaped mite body with 8 legs. Measures 0.35-0.4 mm long. | |
| D. brevis | Overlapping body sections. Measures 0.15-0.2 mm long. |
Microscopes magnify Demodex mites up to 90X their actual size to reveal their physical features and structures.
Demodex Life Cycle
The life cycle of eyelash mites passes through the following stages:
Eggs
Adult Demodex mites lay eggs inside hair follicles. The oval-shaped eggs stick to the hair shaft. They hatch after 3-4 days.
Larvae
Larvae emerge from eggs and develop into a nymph stage in about 5 days. They have six legs at this stage.
Protonymph
The six-legged larva progresses into an eight-legged protonymph after 5 more days. The protonymph crawls out of the follicle to mate.
Deutonymph
After mating, the protonymph develops into an adult-shaped deutonymph with an elongated body. The mites crawl into hair follicles to finish maturing.
Adult
In 14-18 days after hatching, the deutonymph becomes an adult Demodex mite. Adults live inside follicles and mate to lay up to 25 eggs over a two-week period.
The entire life cycle takes about 3-4 weeks. Mites can survive 2-3 days outside of a follicle without feeding.
Are Eyelash Mites Visible?
No, Demodex folliculorum and Demodex brevis cannot be seen with the naked eye. These microscopic mites are smaller than the width of a hair strand. The average person has 1-2 mites per eyelash follicle.
Even with an infestation, it’s unlikely to see the mites crawling on lashes or skin. Magnification of 20-25X is required to view Demodex. Doctors use microscopes to identify them.
How Do You Get Rid of Eyelid Mites?
Most people don’t need to treat eyelash mites. Gently washing the eyes daily with lid scrubs can remove dead skin cells and oils where mites thrive. If you have a mild infection with irritation, a doctor may prescribe:
- Antibiotic ointment to apply on the eyelid margins
- Baby shampoo lid scrubs
- Warm compresses
- Artificial tears
For a moderate infestation, a doctor may prescribe medicated shampoos and ointments containing ingredients like:
- Tea tree oil
- Metronidazole
- Crotamiton
- Permethrin
Oral ivermectin is sometimes prescribed for a severe Demodex infestation. Removing makeup daily and treating any underlying skin condition can also help reduce mite populations.
Preventing Demodex Infestations
You can’t completely prevent or eliminate eyelash mites, since they occur naturally on most adults. But you can reduce the risk of having too many by:
- Gently washing the eyes and face daily
- Properly removing makeup each night
- Avoiding sharing towels, pillowcases, and other items that contact the eyes
- Treating any underlying skin conditions like rosacea
- Not suppressing the immune system with medications
Proper hygiene helps control the Demodex population to avoid an infestation.
Conclusion
Eyelash mites are microscopic parasites named Demodex folliculorum and Demodex brevis that live in the hair follicles of most adults. They have a tiny elongated body about 0.3-0.4 mm long with eight stubby legs. These blind mites feed on oils and skin cells inside the follicles.
Finding Demodex under a microscope confirms their presence. Though harmless at normal levels, a rapid overgrowth causes symptoms like eye irritation, missing lashes, and redness. Mild cases can be treated with lid hygiene and topical medications. Severe infestations may require oral medication. Proper face washing and makeup removal help control Demodex populations.
