Extra eyelashes in dogs – distichiasis

Overview

The term used in examination reports is distichiasis, while a single extra eyelash is called a distichia. The hair emerges from or beside a gland opening on the eyelid edge.

These oily eyelid glands are called Meibomian glands. Their normal role is to produce secretions that lubricate the eye's surface.

A gland opening should not normally produce a hair. Extra hairs may affect just one eyelid or all four.

The condition can affect both upper and lower lids, although dogs normally have no eyelashes on the lower lids. Extra eyelashes are often found in both eyes.

Some dogs live their whole lives without problems from the extra lashes.

The name does not mean a complete additional row of eyelashes: dogs usually have individual hairs growing in the wrong place.

Causes

An abnormally positioned hair follicle

The extra eyelash's follicle lies within or very close to an eyelid gland. Abnormal differentiation of the gland may create a hair-producing structure in that area.

The precise reason a follicle develops in the wrong place is unknown. Inheritance involves multiple factors rather than one simple genetic defect.

No single major genetic variant explaining canine distichiasis has been identified. Symptom severity depends particularly on the hair's thickness and direction of growth.

A stiff hair touching the eye rubs the cornea and may damage its surface cells. Hairs can fall out naturally and reappear during the hair growth cycle.

More than one extra hair may grow from a single gland opening.

A hair growing through the inner eyelid surface

An ectopic cilium grows through the conjunctiva on the inner eyelid surface directly towards the eye. It may emerge a few millimetres from the lid edge.

It generally causes much greater pain and corneal damage than a soft eyelash on the lid margin. In trichiasis, a normally positioned eyelid or facial hair instead points towards the eye's surface.

In entropion, hairs may touch the cornea because the whole eyelid edge turns inwards.

Risk factors

Extra eyelashes are often detected early, usually before 1–2 years of age. However, new abnormal hairs can become visible at any age.

Predisposed breeds include American and English Cocker Spaniels and Poodles. Extra eyelashes are also often found in Cavalier King Charles Spaniels, Shih Tzus, Lhasa Apsos and Shetland Sheepdogs.

Other risk groups include Golden Retrievers, Boxers, Yorkshire Terriers and Pekingese. Among 1,156 Havanese eye-tested in Norway between 2005 and 2020, 168, or 14.5%, had distichiasis.

The study found no statistically clear difference in prevalence between males and females. Extra eyelashes were found in 13.1% of males.

The corresponding proportion of females was 15.3%. Among Labradoodles attending breeding eye examinations in the Netherlands between 2014 and 2024, extra eyelashes were found in 30 dogs, or 2.5%.

These figures describe studied groups in different countries, rather than the risk for all dogs.

Typical symptoms

Distichiasis causing few symptoms may only be found during an eye check, even if the eyes look normal at home.

• The eye waters more than before.

• The eye or conjunctiva is red.

• Your dog blinks more often than usual.

• Your dog squints or keeps the eye partly closed.

• Mucus or other discharge comes from the eye.

• Your dog rubs the face or tries to scratch the eye with a paw.

• Light may be uncomfortable and increase squinting.

A bluish area of cornea or one that has lost its shine may be associated with an ulcer. The amount of pain is not directly proportional to the number of extra lashes.

In the Havanese study, 86.9% of affected dogs were classified as mild cases. Moderate cases accounted for 2.4%.

Severe cases accounted for 0.6%. Severity was not recorded for 10.1% of diagnosed cases.

Complications and consequences

Persistent rubbing and corneal ulcers

Constant rubbing can ulcerate the cornea and make it susceptible to bacterial infection. Longstanding irritation may cause white corneal scars.

Dark pigment may also accumulate in the cornea. Growth of new blood vessels into the cornea is another possible consequence of persistent damage.

These chronic surface changes can impair vision. A deep corneal ulcer can perforate the eye and threaten preservation of the eyeball.

Your dog may worsen the damage by scratching or rubbing the eye.

Outlook and treatment complications

The outlook for a dog without symptoms is excellent without removing the lashes. The outlook after surgery is generally good, but new hairs may need further treatment.

Electrocautery or freezing can cause excessive eyelid scarring.

Diagnosis at the vet

Finding the eyelashes and examining surface damage

The vet checks where hairs emerge and whether they touch the conjunctiva or cornea. Small hairs often require magnification to see their origin clearly.

An extra eyelash may be missed if it is the same colour as the normal eyelid hair. Swelling of the inner lid surface can make an ectopic cilium harder to find.

Assessment of tear production helps establish whether dryness contributes to symptoms. Fluorescein staining identifies areas with damaged corneal surface cells.

A very painful dog may need local anaesthesia or sedation for a thorough examination. Other possible causes are investigated too, because not every extra eyelash causes a problem.

In the Norwegian study, 49 dogs changed from an unaffected result to a distichiasis finding between their first and last examinations. This may reflect lashes appearing later or a mild finding missed initially.

Official eye screening

Some official screening schemes record distichiasis and ectopic cilia within the same diagnostic group. A severe result may be recorded when lashes are numerous or cause observable irritation.

Stiff, hard lashes and ectopic cilia also fall within findings classified as severe. Corneal swelling, blood vessels or pigment at the point of hair contact help assess the significance of irritation.

In such schemes, a previous distichiasis diagnosis remains valid even if no extra hairs are visible at a later examination.

Official eye screening examines the front and back of the eye as well as the lids to identify other conditions.

Treatment

A symptom-free finding and mild irritation

The vet chooses treatment according to symptoms and surface damage; not every eyelash needs removal. For mild signs, an eye ointment can lubricate both the cornea and the hair touching it.

Plucking provides only temporary relief because the follicle continues producing new hair. A regrowing hair may be thicker or stiffer than before.

Plucking may therefore be an interim measure, for example while a dog awaits more lasting treatment or cannot undergo general anaesthesia.

Treating the follicle

Lasting treatment aims to destroy the follicle of the hair causing symptoms. The follicle can be treated by freezing, electrocautery or laser.

Cryotherapy freezes the affected eyelid area with a special cold probe. While destroying the follicle, the lid margin must also be protected from injury.

If a lid has only one or two troublesome hairs, a small section containing their follicles may sometimes be removed surgically. An ectopic cilium growing through the inner lid surface is usually removed surgically with its follicle.

Surgical treatments take place under general anaesthesia. A severe or complex case may be referred to a veterinary eye specialist.

Recovery and recurrence

Swelling and discomfort are usual during the first 2–3 days after cryotherapy. The lid margin may temporarily lose colour, with pigment generally returning within 4–6 months.

New eyelashes may grow from previously untreated follicles. Inadequate freezing of a follicle can also allow hair to regrow at the treated site.

Cryotherapy may be repeated when necessary if new troublesome lashes appear. The eyes are monitored for several months after surgery for new hairs.

A concurrent corneal ulcer may need topical antibacterial medication. A protective collar can prevent rubbing and further injury during healing.

Pain from a corneal ulcer may require vet-prescribed pain relief. An uncomplicated ulcer often heals within 3–5 days, but continuing hair contact can prevent healing.

Prevention

Ordinary home care cannot prevent extra eyelashes from developing. Some breeding guidance allows consideration of a dog with mild findings if paired with an examined, unaffected mate.

Clearly symptomatic distichia and ectopic cilia are reasons not to breed from a dog. Mating two dogs affected by extra eyelashes is not recommended.

Removing eyelashes through treatment does not change the original inherited eye disease diagnosis to unaffected. DNA testing does not replace a breeding dog's clinical eye examination.

Eye examinations also monitor other inherited eye diseases within the breed, such as cataracts.

Important for dog owners

Record when watering, squinting or rubbing began and whether only one eye is affected.

Keep the eye examination report and details of lashes already removed. Tell the practice about previous cryotherapy or surgery so that a new finding can be considered alongside the treatment history.

If a dog receiving topical treatment keeps rubbing the eye or develops a corneal ulcer, the treatment approach needs reassessment.

Removing lashes before examination can make the original finding harder to assess, so tell the examiner about earlier treatment.

Agree a follow-up appointment with your vet and follow the care instructions. New severe pain or cloudiness is a reason for immediate contact even in a dog whose extra eyelashes previously caused no symptoms.

Frequently asked questions

Must every extra eyelash be removed?

Very fine, soft lashes may cause no symptoms and need not be removed simply because they are present. Numerous or stiff lashes touching the eye surface cause symptoms more often and may therefore need vet-planned treatment.

Why does a plucked eyelash grow back?

Plucking removes the visible hair but leaves the follicle in place, so relief is usually temporary. More lasting treatment targets the follicle, for example with freezing or electrocautery. New hairs may later emerge from other, previously untreated follicles too.

How do distichiasis and an ectopic cilium differ?

In distichiasis, an extra hair emerges from the free eyelid edge, usually through a gland opening. An ectopic cilium grows through the inner eyelid conjunctiva directly towards the cornea, generally causing substantially more pain and surface damage.

How long is the eyelid swollen after freezing?

Moderate swelling and discomfort usually occur during the first 2–3 days, then gradually improve. Pigment may take 4–6 months to return, so the colour change can last much longer than the swelling.

Is there a DNA test for extra eyelashes?

Canine distichiasis involves multiple factors, and no single major genetic variant explaining the condition is known. Breeding choices therefore require clinical eye examinations; dogs with severe symptoms or ectopic cilia should not be bred from.