Tear Stains and Blocked Tear Ducts in Dogs: Causes, Care, and Treatment

How tears normally drain

A thin film of tears keeps the eye moist and clean. Extra fluid drains through two tiny openings at the inner corner of each eye, one on the upper lid and one on the lower lid. Short channels lead from these openings into a small sac, and from there the nasolacrimal duct carries the tears into the nose.

When any part of this path is narrowed, blocked, or hard for tears to reach, they spill over the lower lid instead. The fur below the eye stays damp and slowly turns reddish-brown. The color comes from porphyrins, iron-containing pigments that are a normal part of tears. It shows most on white and cream coats, although dogs of any color can have tear overflow.

Common causes

There are two broad reasons for tear overflow. Either something irritates the eye and it makes extra tears, or the tears cannot drain properly. Vets commonly find one or more of the following.

• Face shape. In flat-faced breeds such as Pugs, Pekingese, and Bulldogs, the eyes sit in shallow sockets, and tears can roll off the face before they reach the drainage openings.
• Hair at the inner corner of the eye that covers the openings or draws tears onto the face.
• Eyelids that roll inward (entropion) or outward (ectropion), or extra eyelashes that rub the eye.
• Conjunctivitis, allergies, corneal ulcers, and other eye infections or injuries.
• Glaucoma, a painful rise in pressure inside the eye.
• A tear duct blocked by inflammation, debris, scar tissue after an injury, or a foreign object such as plant material. Rarely, a growth near the duct presses on it.
• A drainage opening that never formed, called an imperforate punctum. It is an uncommon cause and shows up in young dogs.

A dog whose eye looks white and comfortable, with clear tears running down the face, most often has a face shape or drainage problem. Tearing that comes with redness, squinting, or thick discharge points more toward irritation, infection, or pain.

If a blockage lasts, the small sac at the start of the duct can become inflamed and infected. This is called dacryocystitis. It can cause swelling at the inner corner of the lower lid, sticky discharge from the drainage openings, and conjunctivitis that does not clear up with the usual treatment.

Signs to watch for

Most owners notice the stain first. The eye and the skin around it are worth a look too.

• Wet fur or a damp streak below the inner corner of one or both eyes
• Reddish-brown staining of the fur under the eyes
• An odor from the area, or red and irritated skin
• Discharge that is thick, sticky, yellow, or green instead of clear
• Swelling at the inner corner of the lower lid
• Squinting, rubbing the eye, or holding it shut

When to see a vet quickly

Long-standing tear stains in a dog who seems comfortable are not an emergency, although a routine vet check is still a good idea. Staining that appears in a dog who never had it before is also worth a visit. Some signs call for a visit the same day or as soon as you can. These include squinting, keeping the eye closed, or pawing at it, which often mean pain. A cloudy or bluish look to the eye, a visible wound, or sudden heavy tearing after a walk through tall grass or brush also need prompt attention. So do a painful swelling at the inner corner of the eye and thick yellow or green discharge. Eye problems such as corneal ulcers can get worse quickly and may affect vision if they are not treated.

How vets find the cause

The vet will usually start with a full eye exam, looking at the eyelids, the lashes, the surface of the eye, and the drainage openings at the inner corner. They may also measure tear production and the pressure inside the eye. A common next step is a fluorescein test. A drop of harmless dye is placed in the eye. If the drainage system is open, the dye usually appears at the nostril within a few minutes. If it does not show up, the vet will look further, since a missing result does not always mean a blockage. The same dye also highlights scratches and ulcers on the surface of the eye.

Flushing is often the next step. The vet passes a very fine, blunt tube into an opening at the inner corner and gently pushes sterile saline through the duct. Fluid at the nose shows the duct is open. Resistance, or fluid and discharge coming back out of the other opening, points to a blockage. Many dogs need sedation or a short anesthetic for this. For long-standing or unclear blockages, the vet may recommend X-rays taken after a contrast dye is placed in the duct, or other imaging.

How it is treated

Treatment depends on the cause the vet finds.

Flushing can clear debris and reopen a blocked duct, and a foreign object such as plant material can often be flushed out or removed. If the duct is likely to close again, the vet may leave a thin, soft tube in it for several weeks while it heals. If the sac or duct is infected, the vet may prescribe antibiotic eye drops, and sometimes medicine by mouth as well.

When a drainage opening never formed, a small procedure can open it. A tube is often left in place for several weeks afterward so the new opening stays open.

Eyelid and eyelash problems are treated at their source. Inward-rolling eyelids are usually corrected with surgery, and extra lashes that rub the eye can be removed. Infections, allergies, ulcers, and glaucoma each need their own treatment. In rare cases where the drainage system is badly damaged, a specialist can create a new route for tears to drain.

For dogs whose face shape is the main cause, there may be no complete fix. Many of these dogs have tearing that comes and goes throughout life, and good daily care keeps the skin healthy. Long-term, low-dose antibiotics are no longer recommended for tear stains, because this use helps bacteria become resistant. Some vets suggest a daily probiotic. There is some evidence it helps, although results can take a couple of months. Ask your vet before starting any tear stain product or supplement.

Everyday care and prevention

Some causes cannot be prevented. Simple daily care still keeps the area clean and helps you notice changes early.

Wipe the area once or twice a day with a clean, soft cloth or cotton pad. Dampen it with warm water or with an eye-safe cleanser your vet recommends, wipe away from the eye, and use a fresh pad for each eye. Pat the fur dry afterward. A damp coat lets staining build up and can lead to skin irritation or yeast growth.

Keeping the hair around the eyes short also helps. Long hair can cover the drainage openings and hold moisture against the skin. A groomer or your vet can trim it safely with blunt-tipped scissors. Vets advise keeping whitening products, peroxide, and household cleaners away from the face, because they can seriously injure the eye if they get in. Eye drops are best used only when your vet has prescribed or approved them.

Fur that is already stained tends to stay discolored. Once the tearing is under control, new hair grows in clean, and the stained hair can be trimmed away as it grows out. It is also a good habit to check your dog's eyes after walks through long grass or brush, and regular checkups let your vet catch eyelid and eyelash problems early.

Rescued and newly adopted dogs

At Paw Squadron, the first stops after every rescue are the vet and a bath. Each animal gets a checkup, deworming, and treatment against fleas and other parasites. Every animal also gets treatment, vaccinations, and a microchip before adoption.

Dogs who lived on the street or in a shelter may arrive with long, matted hair around the eyes that traps tears and debris. A trim and gentle cleaning are often part of settling in. If your new dog has tear stains, mention them at the first visit to your own vet and bring any health records you received, so the vet can see what was already checked.

Eyeworms are another cause of watery eyes worth knowing about. These thin, white worms live on the surface of the eye and under the eyelids. Small flies that feed on tears carry them from one animal to the next. They are found in many parts of Europe, and cases in dogs have been reported in the Balkans, including Bulgaria, Serbia, and Greece. An infected dog may have tearing, discharge, or red eyes, or may rub at its face. A vet can usually spot the worms during an eye exam, remove them, and advise on treatment. The same flies can also infect cats and, rarely, people.

A blocked tear duct and the staining it causes do not spread to other pets or to people. Some eye infections can pass between animals, so if the discharge is thick or colored, it makes sense to use separate cloths for each pet until your vet has checked the eye. If you are thinking about giving a dog a home, you can meet the dogs looking for families on our Adoptions page and find more care guides in PawPedia.