Most of the time, humans and Demodex mites coexist with no problem. But on occasion, the mites can multiply exponentially, resulting in an infestation that can manifest with red, irritated eyes and itchy, crusty eyelids, known as demodicosis.
When a mite infestation is diagnosed, it can be treated with over-the-counter or prescription medications in combination with good hygiene.
Symptoms of Eyelash Mites
When demodicosis occurs, it can lead to blepharitis (inflammation of the eyelids), which in turn leads to keratitis (inflammation of the cornea). Common symptoms of demodicosis include:
Itching, crusting, redness, and swelling of the eyelidBurning sensation in the eyeFeeling of a foreign object in the eyeEye rednessWatery eyesBlurry visionExtreme sensitivity to light
Demodicosis is most commonly bilateral (affecting both eyes), although roughly a third of all cases will only affect one eye.
Complications
Demodicosis is often uncomplicated but can sometimes lead to additional symptoms, especially if the infestation is severe and left untreated. These include:
Conjunctivitis: The inflammation of the conjunctiva (the clear membrane covering the white of the eye). This differs slightly from pink eye, which is the common name for the viral form of infectious conjunctivitis. Chalazia: A bump on the eyelid caused by blockage of an oil gland called the meibomian gland Trichiasis: A condition in which eyelashes grow inward, causing irritation and pain Madarosis: A condition in which eyelashes become brittle and fall out
Causes
Demodex mites are most prevalent on the face and are easily transmitted from person to person with close physical contact. The mites are usually benign and go about their normal life cycle, laying eggs near the ducts of the sebaceous glands, without any notice.
Although the mite population is usually well-controlled by the immune system, they can sometimes overproliferate if the microbiome of the eyelid is changed. When this occurs, the increased number of mites (and increased accumulation of eggs and larva) can trigger an inflammatory response, resulting in the blockage of the sebaceous glands.
Demodex mites often are first passed from mothers to newborns, particularly those who are breastfed. But because the mites subsist on skin cells and sebum (skin oil)—both of which babies and young children produce in low quantities—infestations are uncommon until the child gets older.
Demodex mites become more prevalent during puberty as the number of sebaceous glands increases. The risk is further increased if the eyelids are not part of daily hygiene practices.
There are several risk factors for demodicosis:
Age: Demodicosis is most common in adults between the ages of 20 and 30 whose sebum production is at its highest, and in adults over 60 whose immune systems are increasingly less able to control mite overgrowth. Sex: Men are almost twice as likely to experience demodicosis than women. This may be due in part to the use of eye makeup in women and the regular cleansing of the eyelids with makeup remover. Weakened immune system: Immunocompromised people (including organ transplant recipients, people with advanced HIV, and those undergoing chemotherapy) are more likely to experience infestations. Rosacea: A condition that causes skin redness and often small, pus-filled bumps on the face. Those with rosacea may have a higher risk of developing an increased load of demodicosis.
Diagnosis
An ophthalmologist or optometrist can diagnose demodicosis by using a slit-lamp to illuminate and magnify structures in and around the eye and eyelid. Cylindrical dandruff on the eyelash is a classic sign of Demodex infestation.
The healthcare provider may also obtain an eyelash for examination under the microscope. A fluorescent dye, called fluorescein, can provide greater contrast and help identify Demodex eggs, larvae, and adult mites.
Demodicosis is often missed in the initial diagnosis because it mimics other common eye conditions such as conjunctivitis, infectious keratitis, and dry eye syndrome. In some cases, it may not be diagnosed until the symptoms fail to respond to a prescribed treatment.
Treatment
The goal of demodicosis treatment is to reduce the number of Demodex mites and prevent the recurrence of infestation. The treatment may include topical or oral medications, used alone or in combination.
Over-the-Counter (OTC) Therapies
There are several OTC topical medications commonly used in the treatment of mild demodicosis:
Cliradex: Cliradex is a natural medication made with a component of tea tree oil called terpinen-4-ol (T40). Available as a foam cleanser or as single-use moist towelettes, Cliradex is applied to the eyelid twice daily for six to eight weeks (roughly two life cycles of the Demodex mite). Tea tree oil: Tea tree oil, a common home remedy, should only be applied to the eyelid or near the eye when diluted, as it can cause irritation, redness, and swelling in its pure form. Still, tea tree oil has been shown to be an effective treatment for demodicosis.
Speak to your healthcare provider before trying any home or OTC remedy to ensure it is safe to use around your eyes.
Prescriptions
Because relapse is common in people with moderate to severe demodicosis, prescription drugs may be needed. These include:
Eurax (crotamiton): Available as a 10 percent cream, Eurax is applied to the skin for seven to 10 days. A second course may be prescribed if the infestation persists. Common side effects include itchiness and rash. Flagyl (metronidazole): This antibiotic medication may be prescribed topically or orally for 14 days. When taken by mouth, Flagyl can cause headache, nausea, diarrhea, constipation, or a metallic taste. Topical metronidazole can cause stinging or burning. Ivermectin: This antiparasitic drug is used for severe cases, particularly in immunocompromised people. The oral drug, known by the brand name Stromectol and others, may only require one to two doses. Dizziness, nausea, stomach upset, diarrhea, and constipation are common side effects.
Coping
In addition to medications, there are other things you can do to ease symptoms of demodicosis and make the treatments more effective. Among them:
Avoid rubbing or scratching the eyes. Place a warm washcloth on top of the eyelid to help clear away crustiness. Dab rather than wipe. Clean the skin around the eyes twice daily with a gentle, non-soap cleanser like Cetaphil. Avoid wearing eye makeup until the symptoms are fully resolved. Change from contact lenses to eyeglasses until the treatment is complete.
To avoid relapse after treatment, avoid greasy eye makeup and oil-based cleansers that can promote Demodex overgrowth. Never use someone else’s eye makeup.
A Word From Verywell
As off-putting as it may sound, an infestation of eyelash mites is common and relatively easy to treat.
One of the best ways to prevent demodicosis is to wash your eyelids regularly (something that men often miss when washing their faces). By taking an extra second or two to gently wipe the eyes with a moist facecloth, you can avoid the buildup of sebum or skin cells that Demodex mites feed on.
