Eyelash mites (Demodex): why an itchy, crusty lash line keeps coming back

Itchy lash roots, a gritty feeling and a crust along the lash line every morning: it is a pattern that settles for a fortnight and then comes back. Sometimes the cause is a mite that lives in the eyelash follicle. Demodex is real, it is very common, and it does not mean anyone has been unclean. Here is what the evidence says, what treatment exists, and where its limits are.

Are eyelash mites real, and does everyone have them?

Yes, they are real, and many adults carry them without any symptoms. Demodex mites are microscopic parasites that live in hair follicles, and on the eyelids they sit in the follicles of the lashes. One study of 1,499 patients at eye clinics in Warsaw found mites on the lashes of 47% of them. The rate climbed with age, from 8% in the youngest group to 77% in people over 70.

That is a Polish clinic population, so I would not quote the exact figures as a Malaysian rate. The lesson travels well enough: finding a mite is not the same as having a disease. The trouble starts when the numbers or the reaction to them tip over into inflammation of the lid margin, the edge of the eyelid where the lashes grow. That inflammation is blepharitis, and mites are one of its possible causes.

What are the waxy collars at the base of the lashes?

They are called collarettes, and they are the sign that points most directly to Demodex. A collarette is a cylindrical, waxy sleeve of debris that wraps around the base of a lash like a small collar. It is made of keratinised cells, undigested material, egg casings and dead mites. The review I relied on calls collarettes the pathognomonic sign of Demodex blepharitis, which means the one finding that is specific to it.

You will not see a collarette well in a mirror. Doctors find them by looking at the lash roots under the slit lamp, the bright microscope used in every eye clinic, while you look downwards so the upper lid margin is exposed. The mites themselves are far too small to see.

So the useful question at an eye appointment is not whether mites are present. It is whether the collarettes and the inflamed margin explain the symptoms, and whether something else is contributing. Ask what was seen at the lash roots, how the lid margin and the oil glands looked, and what each finding means for the plan. A clear answer to that is worth more than a product bought after a search.

Why do my lids itch and go red, and is it my make-up or my skin?

Demodex is one cause of itching, redness and a burning feeling on the lid margin, but it is not the only one, and it can sit alongside the others. The reported symptoms are redness, dryness and itching. The same features can come from blepharitis without mites, from an allergic or irritant reaction to cosmetics or lash glue, and from dry eye. The NHS lists the same set for blepharitis: sore eyelids, itchy eyes, a gritty feeling, and flakes or crusts around the lash roots.

Skin matters too. In the Warsaw study, 76% of people with blepharitis had mites, against 47% overall, and 67% of people with rosacea did. Rosacea is a long-term inflammatory skin condition that often affects the face and can involve the eyelids; Dr Ong Jin Khang of The Retreat Clinic writes about it from the skin side in rosacea and the eye. I have found no source that tests whether lash extensions or make-up cause Demodex, so I will not claim it. What I can say is that a red, itchy lid margin has several possible causes, and one look at the lash roots sorts out more than a guess does.

Will lid hygiene and tea tree products clear it?

They can help the surface, but a review of the prescription drop reports that most patients treated this way still had unresolved disease. The NHS advice for blepharitis is to soak a clean flannel in warm water and hold it on the closed lid for 5 to 10 minutes, then gently clean the lid margin with cotton wool, and to carry on cleaning even after symptoms clear. It is a sensible routine for the lid margin, and I would not drop it, but it is not designed to kill mites.

That review lists warm compresses, artificial tears and tea-tree-oil based lid products as the traditional care, and reports that dry eye treatment alone does not deal with Demodex blepharitis. I will not give tea tree oil strengths or home mixtures. Which product suits which lid is a question for the doctor who has looked at the lashes.

What is the prescription drop for eyelash mites?

It is lotilaner 0.25% eye drops, a medicine that paralyses the mites and so starves them. It blocks GABA-gated chloride channels in the mite, which leads to paralysis. The US prescribing information gives the indication as Demodex blepharitis, one drop in each eye twice daily, about 12 hours apart, for 6 weeks. Six weeks is chosen to cover at least two full life cycles of the mite, which the review puts at about 14 to 23 days each.

A systematic review pooling four studies and 947 people found that collarettes were cleared far more often than with the vehicle drop (relative risk 5.05, 95% confidence interval 3.75 to 6.81), and mite eradication was also higher (relative risk 3.80). Contact lenses come out before the drop and can go back in after 15 minutes. The commonest reaction on the label was stinging or burning at the time of the drop, in 10% of people. The label says safety in people under 18 is not established.

Two cautions. These trials were part of the manufacturer's development programme, and a trial result describes a group, not one person. And I have no source on whether lotilaner is registered or supplied in Malaysia. Availability varies from country to country, so this is a question for a doctor or pharmacist, not something I can promise.

Why does it keep coming back, and what should I do?

The NHS says blepharitis symptoms often come and go, and it advises carrying on with lid cleaning even after they clear. Clearing mites deals with one cause. It does not treat the others on the list above, such as a cosmetic reaction or dry eye. So the sensible approach is to find out which cause is at work, treat that, and keep up the daily lid care.

The action is a proper look. See a doctor who can examine the lash roots under a slit lamp, which in practice means an eye doctor. If crusted, red lids do not improve or they get worse, the NHS says to see a GP. Pain in the eye, a change in vision such as blurring or loss, or a very red eye is different: the NHS says to get urgent help the same day. Lumps on the lid can go with Demodex blepharitis, and the review lists chalazia among its features. A lump that appears during a flare is often a chalazion, and the same review lists lid and lash abnormalities among the signs, so lashes that grow inward are worth checking for as trichiasis. The wider picture of lid, tear film and surface is in the guide to what makes eyes look tired, and the rest of the lid conditions sit under eyelid conditions.

Little Eyes 101's Dr Chan Li Yen writes about blepharitis in children, which matters because the lotilaner label says safety and effectiveness are not established under 18.