Why Is My Dog Having Eye Discharge When Breathing? | PawAI Lab

Eye discharge that coincides with noticeable breathing changes in your dog may reflect a connection between the nasal and lacrimal (tear drainage) systems, or it may indicate a respiratory or ocular condition that requires veterinary attention.

Quick Answer

The eyes and nasal passages in dogs are connected through the nasolacrimal duct, which normally drains tears from the eye into the nose. When a dog has difficulty breathing, nasal congestion, or a respiratory infection, this drainage can be disrupted, causing tears to overflow and appear as eye discharge. Discharge that is clear and linked to temporary nasal stuffiness may resolve on its own, but coloured discharge, breathing difficulty, or persistent symptoms should be evaluated by a veterinarian.

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How Breathing and Eye Drainage Are Connected

To understand why eye discharge may appear when a dog is experiencing breathing changes, it is helpful to understand the anatomy of the tear drainage system.

Dogs, like humans, have a nasolacrimal duct system. Tears produced by the lacrimal gland flow across the surface of the eye and drain through small openings (puncta) located at the inner corner of the eyelid. From there, the tears travel through a duct that empties into the nasal cavity. This is why your dog's nose is typically moist, and it also explains the connection between breathing and eye discharge.

When the normal flow through this drainage system is disrupted, tears can back up and overflow from the eye, creating visible discharge. Several conditions that affect breathing can interfere with this system.

What the Discharge May Look Like

Discharge associated with breathing changes can present in characteristic ways depending on the underlying cause.

Clear and watery overflow: Tears that spill from the eye because they cannot drain properly through the nasolacrimal duct into the nose. This may be most noticeable when the dog is breathing heavily, panting, or has a congested nose.
Thick and mucoid: A stringy, white, or yellowish discharge that may occur when the eye produces excess mucus in response to chronic inflammation or infection. This can be associated with long-standing respiratory or ocular conditions.
Mucopurulent (yellow or green): Thick, coloured discharge that may indicate a bacterial infection in the eye, the nasal passages, or both. This is more concerning than clear discharge and warrants veterinary evaluation.
Bloody or blood-tinged: Discharge that contains traces of blood may be associated with trauma, severe infection, or nasal conditions such as a foreign body or tumour. This requires prompt veterinary attention.
Bilateral vs. unilateral: Discharge from both eyes is more commonly associated with systemic issues such as allergies, respiratory infections, or bilateral nasolacrimal obstruction. Discharge from one eye only may suggest a localized blockage or an issue isolated to that eye.

Possible Causes Linked to Breathing and Eye Discharge

Several conditions that affect a dog's breathing can simultaneously produce or contribute to eye discharge.

Upper respiratory infections. Viral or bacterial infections of the upper respiratory tract (such as canine infectious respiratory disease complex, sometimes called kennel cough) can cause nasal congestion and inflammation. When the nasal passages are swollen or filled with mucus, the nasolacrimal duct cannot drain tears effectively, leading to tear overflow and visible eye discharge. These infections may also directly involve the conjunctiva, causing conjunctivitis alongside respiratory signs.

Nasolacrimal duct obstruction. The duct that drains tears into the nose can become blocked by inflammation, scarring, foreign material, or, less commonly, tumours. When the duct is obstructed, tears have nowhere to drain but out through the eye. Obstruction may be congenital in some breeds (such as Poodles and American Cocker Spaniels) or acquired due to chronic infection or injury.

Allergic rhinitis. Dogs with environmental allergies can experience inflammation of the nasal passages (allergic rhinitis) alongside allergic conjunctivitis. Both the nasal congestion and the direct eye inflammation can lead to visible discharge. This is often seasonal and may be accompanied by sneezing, a clear nasal discharge, and itchy skin.

Brachycephalic obstructive airway syndrome (BOAS). Brachycephalic breeds with compressed facial anatomy (such as Pugs, English Bulldogs, and French Bulldogs) are prone to breathing difficulties due to narrowed nostrils, an elongated soft palate, and other airway abnormalities. The altered facial structure in these breeds can also affect the nasolacrimal duct pathway. Heavy or laboured breathing in these dogs may be accompanied by chronic eye discharge.

Sinusitis or rhinitis. Inflammation of the sinuses or nasal lining, whether due to infection, fungal disease, or foreign material, can disrupt normal tear drainage. Chronic sinusitis may cause persistent, low-grade eye discharge alongside nasal discharge or noisy breathing.

Facial trauma or dental disease. The roots of the upper teeth are located close to the nasal passages and nasolacrimal duct. Severe dental disease (such as tooth root abscesses) or facial trauma can cause inflammation or infection that affects both breathing and tear drainage, leading to eye discharge that seems to worsen with breathing effort.

Foreign body in the nasal passage. A grass seed, plant awn, or other foreign material lodged in the nasal passage can cause sneezing, nasal discharge, laboured breathing, and secondary disruption of tear drainage. Dogs that suddenly develop noisy breathing and eye discharge, especially after being in grassy or wooded areas, should be evaluated promptly.

Bracken fern or plant awn migration. In certain regions, plant material can penetrate the nasal passages and migrate, causing chronic discharge and breathing changes. This is a particular concern in rural or hunting dogs.

What to Monitor

Careful observation can help distinguish between benign tear overflow and discharge associated with a more significant condition.

Breathing pattern: Is your dog breathing faster than normal, panting excessively at rest, struggling to breathe through the nose, or making audible breathing sounds (wheezing, snorting, or stridor)? Laboured breathing at rest is a serious sign that requires immediate veterinary attention.
Nasal discharge: Note whether there is any discharge from the nostrils and, if so, its colour and consistency. Bilateral clear nasal discharge may be associated with allergies or viral infection, while unilateral coloured or bloody discharge may suggest a foreign body or more serious nasal condition.
Discharge timing: Does the eye discharge appear mainly when the dog is breathing heavily (such as after exercise or during stress), or is it present continuously regardless of activity level?
Appetite and energy: A dog with a respiratory condition that is severe enough to affect tear drainage may also show reduced appetite, lethargy, or reluctance to eat (which can indicate nasal discomfort, as dogs rely on their sense of smell to eat).
Facial symmetry: Observe your dog's face from the front. Swelling on one side, uneven pupil size, or asymmetrical eye appearance can indicate a serious condition.
Sneezing or reverse sneezing: Frequent sneezing, reverse sneezing episodes, or pawing at the nose alongside eye discharge may suggest a nasal foreign body or irritant.

What You Can Do

While veterinary evaluation is important for persistent or concerning symptoms, some at-home measures may provide comfort and useful information.

Observe and document: Note the breathing pattern, type of discharge, timing, and any other symptoms. Recording a short video of your dog's breathing when you notice the discharge can be very helpful for your veterinarian.
Keep the eyes clean: Gently wipe discharge from the eyes using a clean, damp cotton ball moistened with warm water or sterile saline. Use a separate cotton ball for each eye and wipe from the inner corner outward.
Use a humidifier: Adding moisture to the air, particularly in dry environments or during winter, may help soothe both the nasal passages and the eye surface.
Limit strenuous activity: If your dog is experiencing breathing difficulty, restrict exercise to gentle, short leash walks until the cause is identified and addressed.
Do not attempt to remove a suspected nasal foreign body: Inserting objects into the nose can push foreign material deeper and cause serious damage. Leave removal to a veterinarian.

When to Contact a Veterinarian

Contact a veterinarian promptly if any of the following are observed:

Laboured or noisy breathing at rest, or visible effort to breathe
Eye discharge that is yellow, green, bloody, or thick and persistent
Nasal discharge, particularly if coloured, bloody, or from one nostril only
Discharge from one eye that is accompanied by facial swelling or asymmetry
Sneezing fits, reverse sneezing, or pawing at the nose
Reduced appetite, weight loss, or lethargy alongside breathing and eye changes
A sudden onset of symptoms, especially after outdoor activity in grassy or wooded areas
Brachycephalic breeds showing increased breathing effort or new discharge patterns

Difficulty breathing can be a sign of a serious condition, and eye discharge that coincides with respiratory changes should not be dismissed as a minor issue. When in doubt, seeking veterinary advice is the safest course of action.

Frequently Asked Questions

Can a blocked nose cause eye discharge in dogs?

Yes, the tear drainage system (nasolacrimal duct) connects the eyes to the nasal cavity. When the nose is congested due to infection, allergy, or anatomical narrowing, tears cannot drain properly and may overflow from the eye as visible discharge. This is a common reason for clear, watery eye discharge that appears alongside nasal congestion.

Why does my dog get eye discharge when panting heavily?

Heavy panting changes the airflow around the face and can increase evaporation from the eye surface, triggering reflex tear production. In brachycephalic breeds, panting may also temporarily compress the nasolacrimal drainage pathway, contributing to overflow. If the discharge is clear and resolves after the dog rests, it may be related to the panting itself, but persistent or coloured discharge should be assessed.

Is eye discharge linked to kennel cough?

Kennel cough (canine infectious respiratory disease complex) primarily affects the upper respiratory tract, causing coughing, nasal discharge, and sometimes mild fever. The associated nasal inflammation can disrupt tear drainage, leading to secondary eye discharge. Some of the organisms involved can also cause direct conjunctivitis. If your dog has been in contact with other dogs and develops coughing alongside eye discharge, veterinary evaluation is recommended.

Can dental problems cause both breathing changes and eye discharge?

The upper tooth roots in dogs are located near the nasal passages and the nasolacrimal duct. A tooth root abscess or severe dental infection can cause inflammation in this area, potentially affecting both breathing and tear drainage, which may produce eye discharge. This is one reason why persistent, unexplained eye discharge may warrant a dental examination as part of the veterinary workup.

Not sure if your dog's symptoms need urgent care? Try PawAI Lab's Symptom Triage Tool for a quick, evidence-based assessment you can use at home before your vet visit.

Sources

American College of Veterinary Ophthalmologists (ACVO)
American Kennel Club (AKC) Canine Health Resources
Royal College of Veterinary Surgeons (RCVS) Knowledge Hub
Veterinary Information Network (VIN)
Cornell University College of Veterinary Medicine
Merck Veterinary Manual

Disclaimer

This article is for informational purposes only and does not constitute veterinary advice, diagnosis, or treatment. If your dog is experiencing eye discharge or any other symptom, consult a qualified veterinarian for a professional evaluation. PawAI Lab's Symptom Triage Tool is designed to provide general guidance and is not a substitute for veterinary care. Always seek professional veterinary attention for persistent, worsening, or concerning symptoms.