Patient guide
Eyelash mites (Demodex blepharitis): the crust at the base of the lashes
By Dr. Sam Khoury, Optometrist7 min read
Lid problems like this are usually slow and affect both eyes. Call the same day if any of these apply: pain rather than itching or grittiness, a change in your vision, new light sensitivity, one eye red and the other not, thick discharge, or an eyelid that is swollen, hot to the touch and spreading. Swelling around the eye with a fever needs to be seen right away. You can contact the office at (609) 246-0236. If the office is closed, or you cannot reach us, go to a hospital emergency room — most have an ophthalmologist on call.
If the edges of your eyelids itch, especially first thing in the morning, and there is a fine crust clinging to the base of the lashes, mites are the most likely explanation. It sounds worse than it is. They are common, they are not a sign of poor hygiene, and they can be treated.
What the mites are
Demodex are microscopic mites that live in human hair follicles and oil glands. Two kinds matter for the eyes: one lives in the lash follicles, the other deeper, in the oil glands along the edge of the lid. Most adults carry some, and the numbers rise with age. In small numbers they cause no trouble.
The problem starts when the numbers build up. Mites, their eggs and their waste collect at the base of the lashes, and the lid margin reacts with redness, itching and inflammation. That is Demodex blepharitis. Blepharitis simply means an inflamed lid margin, and mites are one of its most common causes.
It matters beyond the itching. The same lid margin holds the oil glands that stop tears from evaporating, and inflammation there is one route into evaporative dry eye. That is why mites are worth looking for in anyone whose dry eye treatment has stalled.
How to recognize it
The sign that gives it away is the collarette: a fine, waxy sleeve wrapped around the base of a lash, like a collar. It is made of mite waste and eggs. Other kinds of blepharitis cause crusting, but not these sleeves, which is why they are treated as the signature of Demodex.
Other things people notice:
- Itching along the lid edge, often worst in the morning.
- Red, thickened or crusty lid margins.
- Lashes that fall out, grow in odd directions or stick together.
- A gritty, something-in-the-eye feeling, burning, or watering.
- Styes or lid bumps that keep coming back.
- Contact lenses that have become uncomfortable to wear.
It becomes more common with age and is more common in people with rosacea, the facial skin condition that also involves the oil glands. It is common in general: in a review of 1,032 patients seen for any reason at six U.S. eye care practices, 58 percent had collarettes. That review was funded by the maker of the prescription drop described below; it counted what was found at examination and did not test any treatment.
What to do at home
Home care keeps mite numbers down. It is slow, and on its own it often does not clear the collarettes completely, but it is the right place to start and it stays useful after any treatment.
Clean the lid margins with tea tree
Tea tree oil is the ingredient with direct published evidence against Demodex. Use a product made for the eyelids, such as Cliradex or Ocusoft Oust, once or twice a day. With the eye closed, wipe along the base of the lashes, upper and lower lids.
Expect some stinging; it is the most common reason people stop. If it is genuinely intolerable, say so rather than quietly giving up, because there is a prescription alternative.
Never put tea tree oil from a health food store near your eyes. Undiluted, it is far too strong for the eye. Only use products made for the eyelids.
Give it six weeks before deciding whether it works.
Makeup, pillowcases and towels
Replace mascara and eyeliner you have been using while your lids have been itchy, and do not share eye makeup. Take makeup off every night.
Wash pillowcases and face towels often, and use your own.
If you also have dry eye
Warm compresses and lid massage still help the oil glands, and they work alongside lid cleaning rather than instead of it. The dry eye guide covers that routine.
What an examination adds
Collarettes are visible in seconds under magnification, usually by asking you to look down so the base of the upper lashes comes into view. The examination also rules out the look-alikes: bacterial blepharitis, allergy, oil gland problems without mites, and eyelid growths that need a different plan. And it checks whether the tear film and the surface of the eye have been affected.
Xdemvy, the prescription drop for mites
Xdemvy (lotilaner) was approved by the FDA in 2023 as the first prescription drop for Demodex blepharitis. It acts on the mites' nervous system and kills them, rather than keeping their numbers down the way lid cleaning does.
One drop in each eye twice a day, about twelve hours apart, for six weeks, and then it is finished. Complete the full six weeks even if the lashes look clean sooner.
Stinging or burning when the drop goes in was the most common side effect in the trials, reported by about one patient in ten.
If you wear contact lenses, take them out first and wait fifteen minutes before putting them back. The drop contains a preservative that can discolor soft lenses. If you use other eye drops, leave at least five minutes between them.
Whether it is the right choice depends on what the examination finds, and coverage for it varies from plan to plan.
Common questions
Did I catch them from my dog or cat?
No. Pets carry their own species of Demodex, which live only on that kind of animal. The mites on human lashes live only on people.
Are they contagious?
They can pass between people through close contact, but most adults already carry some. What causes symptoms is the numbers building up on your own lids, not catching them in the first place. Not sharing eye makeup, towels or pillowcases is still sensible.
Will they come back after treatment?
They can. Treatment brings the numbers down; it does not stop mites returning. Keeping up some lid cleaning afterward helps, and if the itching and crust come back, call.
Is this why my dry eye treatment stopped working?
Sometimes. Mites inflame the same lid margin that holds the oil glands, and a dry eye routine that ignores them can stall. That is why the lashes are part of a dry eye examination.
Does this go through my vision plan or my medical insurance?
If mites or blepharitis are the reason for your visit, it is a medical visit and goes through your medical insurance, even though you are seeing an optometrist. Vision plans cover routine eye exams and eyewear; medical plans cover conditions.
Call with your plan details before you book and it can be sorted out beforehand rather than afterwards.
Book an evaluation
If six weeks of lid cleaning has not settled the itching and crust, or you would rather know what is causing it before you start, the next step is an examination.
Khoury Eye Care, Hamilton Mall, 4403 Black Horse Pike, Mays Landing.