Causes of a Dog’s Swollen Eye

The dog’s eyes are swollen. Swollen, red eyes in dogs can indicate various issues, from simple irritations to more serious conditions. Common causes include allergies, injuries, infections, and even underlying medical conditions. A swollen eye in a dog can be startling, especially if it appears suddenly or looks severe. As pet parents, we’re wired to notice when something’s off with our furry companions. Swollen eyes aren’t just a cosmetic issue—they often point to underlying problems ranging from mild allergies to serious health threats. Understanding what could be behind that puffiness or bulging can help you act quickly and ensure your dog gets the care they need.

Dog eyes are delicate. They’re exposed, prone to injury, and highly reactive to allergens, infections, and trauma. A swollen eye can appear red, teary, or partially closed. Sometimes it’s just one eye, sometimes both. But no matter the appearance, it’s a sign that your dog’s eye—or something around it—is inflamed, irritated, or under attack.

Let’s walk through the most common causes behind this condition, starting with the basics of what eye swelling in dogs really means.

Understanding Eye Swelling in Dogs

What Is Eye Swelling in Dogs?

Eye swelling in dogs refers to puffiness, inflammation, or enlargement around one or both eyes. This can include the eyelids, the tissues surrounding the eye, or even the eyeball itself, appearing more prominent. Swelling might be soft and fluid-filled, hard and dense, or just a general puffiness.

The most common areas where swelling appears include:

The eyelids (upper and/or lower)
The conjunctiva (the pink inner lining of the eyelids)
Around the eye socket (periorbital swelling)
The eye itself protrudes (exophthalmos)

This swelling may be accompanied by other signs like:

Redness
Watery or pus-filled discharge
Squinting
Pawing at the eye
Visible third eyelid
Cloudiness in the eye

Sometimes, swelling is the only visible symptom, but often it’s a package deal that comes with discomfort, discharge, or even a sudden change in behavior.

Common Symptoms Accompanying Swollen Eyes

If your dog has a swollen eye, there are usually other signs to help clue you in on what might be going on. These include:

Excessive blinking or squinting – a sign of discomfort or pain.
Tearing or discharge – clear fluid might indicate irritation, while yellow or green discharge usually points to infection.
Eye rubbing or pawing – dogs instinctively try to relieve irritation by scratching, which can actually worsen the issue.
Changes in behavior – lethargy, loss of appetite, or irritability can indicate systemic infection or pain.

Don’t ignore these signs. Even if the swelling seems minor, it can escalate quickly without proper care.

Environmental Irritants and Allergies

Pollen, Dust, and Mold

Just like us, dogs can suffer from allergies. Airborne allergens like pollen, dust mites, and mold spores can irritate the sensitive tissues around the eyes, causing redness, itching, and swelling. Seasonal allergies are especially common in spring and fall, but can occur year-round depending on your environment.

If your dog’s eye swelling seems to coincide with time spent outdoors, high pollen counts, or dusty environments, allergies are a strong suspect. These allergic reactions typically affect both eyes and may come with sneezing, itchy skin, or licking of the paws.

The signs to look out for:

Swollen eyelids
Red, watery eyes
Excessive tearing or clear discharge
Itchy face or rubbing against furniture

Managing environmental allergies often involves:

Limiting outdoor exposure during peak allergen times
Frequent eye wiping with vet-approved pads
Air purifiers indoors
Allergy medications as prescribed by your vet

Food Allergies and Eye Reactions

Food allergies can also cause eye swelling, although this is less common than environmental triggers. Proteins like beef, chicken, dairy, and wheat are typical culprits. When the immune system misidentifies certain food components as threats, it releases histamines that can cause inflammation throughout the body, including the eyes.

If your dog has persistent eye swelling, especially paired with gastrointestinal issues, itchy skin, or chronic ear infections, a food allergy may be to blame.

Managing food-related eye issues requires:

An elimination diet trial under veterinary guidance
Switching to hypoallergenic or limited-ingredient diets
Long-term avoidance of identified allergens

Chemical Irritants in the Home

Household cleaners, scented candles, air fresheners, or even certain shampoos can cause eye irritation and swelling in dogs. Dogs are often on the floor where chemicals settle, and they tend to sniff everything—including your freshly sprayed room.

If your dog experiences sudden eye swelling after a cleaning session or bath, chemical exposure is likely. Symptoms might include:

One or both eyes suddenly puffy
Redness and squinting
Sneezing or runny nose

In these cases, remove the source, flush the eyes with saline if advised by your vet, and consider switching to pet-safe, fragrance-free cleaning products.

Injuries and Trauma

Scratches from Other Pets

Whether it’s playtime gone wrong or a territorial scuffle, dogs often get scratched near the eyes. A cat swipe, another dog’s paw, or a sharp toy can result in a scratched cornea or bruised eyelid. These types of injuries are common, especially in multi-pet households.

Scratches often result in:

Swelling and redness
Increased blinking or closing of the eye
Clear or bloody discharge
Reluctance to open the eye

Any eye trauma warrants a vet visit. Even a small scratch can lead to a corneal ulcer, which, if untreated, could lead to vision loss.

Foreign Bodies in the Eye

Grains of sand, grass seeds, or tiny bits of debris can get stuck under a dog’s eyelid or on the surface of the eye. This not only causes irritation but can scratch the eye and cause significant inflammation.

Signs of a foreign body include:

One eye suddenly becoming swollen or red
Pawing at the face
Excessive blinking
Tear overflow

Your vet may use a fluorescein stain to detect scratches or flush the eye to remove debris safely.

Accidental Bumps or Hits

Dogs are curious by nature and don’t always look where they’re going. A bump into a table, fall from a height, or even a poorly-timed game of fetch can cause blunt trauma to the eye area. This may lead to swelling, bruising, or internal damage like hyphema (blood in the eye).

In these cases, watch for:

One eye appearing more “popped out” than the other
Swelling around the orbital bone
Signs of pain when touched

Eye trauma isn’t just painful—it can be a medical emergency. Immediate veterinary attention is crucial to prevent permanent damage.

Infections and Inflammation

Conjunctivitis (Pink Eye)

One of the most common causes of eye swelling in dogs is conjunctivitis, or “pink eye.” This condition involves inflammation of the conjunctiva—the pink tissue lining the inner eyelid and covering the white part of the eye. It’s a condition many pet owners recognize because humans can get it too, though the causes in dogs can be different.

Conjunctivitis in dogs can be caused by:

Bacterial infections
Viral infections (like canine distemper)
Allergies
Environmental irritants
Dry eye (keratoconjunctivitis sicca)

Dogs with conjunctivitis usually show symptoms like:

Swollen eyelids
Red, irritated eyes
Mucous or pus-like discharge (yellow or green)
Squinting or blinking
Frequent pawing at the face

Treatment depends on the cause. Bacterial conjunctivitis typically responds well to antibiotic eye drops or ointments. For allergic or viral causes, the vet may prescribe anti-inflammatory or lubricating drops. Whatever the origin, early treatment prevents complications like corneal ulcers or long-term vision problems.

Uveitis and Other Inflammatory Conditions

Uveitis is a more serious form of eye inflammation that affects the inner structures of the eye, including the iris and ciliary body. It’s not as easily visible as conjunctivitis, but one of the symptoms is often a swollen or cloudy-looking eye.

Uveitis can be caused by:

Trauma
Systemic infections (like ehrlichiosis or leptospirosis)
Immune-mediated diseases
Cancer

Signs include:

Cloudiness in the eye
Eye swelling and redness
Pain (squinting, head shaking, sensitivity to light)
Reduced vision

Because uveitis can lead to blindness, it’s considered an emergency. Your vet will likely perform blood tests, ocular pressure readings, and a full physical exam. Treatment includes steroid eye drops, systemic medications, or addressing the underlying condition.

Bacterial, Viral, and Fungal Infections

Beyond conjunctivitis, several other types of infections can affect a dog’s eye. These include bacterial infections from cuts or trauma, viral infections like distemper, or fungal infections from environmental exposure.

Infections often bring:

Significant swelling around the eye
Crusty or thick discharge
Foul odor from the eye area
Fever or lethargy

Fungal infections like blastomycosis can be particularly aggressive and may cause blindness or even affect the brain. These are more common in certain geographic areas, so if you live in a high-risk zone, be vigilant.

Quick diagnosis and prompt antibiotic, antiviral, or antifungal treatment are essential. Leaving infections untreated risks complications like corneal ulcers, glaucoma, or even permanent vision loss.

Parasites and Insect Bites

Eyeworms and Their Effects

Yes, you read that right—eyeworms. These tiny parasites, such as Thelazia, can live in a dog’s tear ducts or conjunctival sac. They’re usually transmitted by flies and are more common in outdoor or farm dogs. While it’s rare, it’s definitely a cause of eye swelling that pet owners should be aware of.

Symptoms of eyeworm infection:

Swollen eyes or eyelids
Increased tear production
Visible white or worm-like structures in the eye
Constant rubbing or scratching

Treatment involves a vet manually removing the worms and administering anti-parasitic medication. It’s not pleasant, but thankfully, it’s treatable and preventable with proper care and parasite control.

Reactions to Bee or Wasp Stings

Insect stings near or on the eyelid can cause sudden, dramatic swelling. Just like in humans, a dog’s immune system might react strongly to a bee sting or wasp attack. The result? A puffy, red, swollen eye that appears to have come out of nowhere.

Sting-related swelling often:

Appears quickly, within minutes
Affects one side of the face
Comes with itching or head shaking
May involve hives or swelling around the muzzle

Mild reactions can be treated at home under vet guidance with antihistamines. However, severe reactions—like difficulty breathing, vomiting, or collapsing—require emergency care, as they may indicate anaphylactic shock.

Prevention involves avoiding areas with high insect activity and keeping your dog away from bee nests or wasp colonies.

Glaucoma and Increased Eye Pressure

How Glaucoma Develops in Dogs

Glaucoma in dogs occurs when fluid inside the eye (called aqueous humor) cannot drain properly, leading to increased intraocular pressure. This pressure buildup can damage the optic nerve and cause partial or complete blindness if not treated promptly.

Primary glaucoma is inherited and more common in breeds like:

Cocker Spaniels
Basset Hounds
Shiba Inus

Secondary glaucoma is caused by underlying issues such as:

Uveitis
Eye tumors
Trauma or infection

Symptoms of glaucoma include:

Swollen or bulging eyes
Cloudy cornea
Excessive tearing
Disorientation or bumping into objects
Dilated pupil that doesn’t react to light

Glaucoma is a medical emergency. It’s very painful and progresses quickly. Vets treat it with medications to reduce eye pressure, pain relief, or in some cases, surgery to save vision or remove a non-functional eye.

Recognizing the Signs of High Eye Pressure

Dogs won’t tell you they have a headache, but signs of elevated eye pressure include:

Reluctance to play or move around
Rubbing the head against walls or furniture
Lethargy and disinterest in surroundings
Eye redness and swelling

You might even notice the eyeball looking slightly out of place. If you observe these signs, go to the vet immediately—delays can cost your dog their sight.

Tumors and Growths

Benign vs. Malignant Growths

Tumors near or around a dog’s eye can cause swelling by pressing against the ocular structures or invading surrounding tissue. These may be benign (non-cancerous) or malignant (cancerous), but either type can interfere with vision and comfort.

Common types of eye-related growths:

Meibomian gland adenomas (benign eyelid tumors)
Melanomas
Lymphomas
Orbital tumors

These growths can cause:

One-sided swelling
Eyelid deformity
Discoloration of the eye or lid
Vision impairment

Even benign tumors can cause problems if they grow too large. Vets may recommend surgical removal, biopsy, or radiation, depending on the diagnosis.

How Tumors Cause Eye Swelling

Tumors exert pressure on surrounding tissues, leading to inflammation and distortion of the eye’s normal structure. Some tumors also bleed or produce fluid, which increases swelling.

Signs that a tumor might be the cause:

Gradual swelling that worsens over weeks
No signs of infection (discharge, redness)
Persistent eye discomfort despite medication

Early intervention is key. If caught early, many eye tumors can be managed or removed before they spread.

Breed-Specific Predispositions

Brachycephalic (Flat-Faced) Breeds

Certain dog breeds are genetically predisposed to eye issues due to the structure of their face. Brachycephalic breeds like Pugs, Bulldogs, Shih Tzus, and Pekingese have shallow eye sockets, making their eyes more exposed and vulnerable.

These breeds often suffer from:

Eye dryness (because they can’t blink fully)
Trauma from rough play or bumping into things
Corneal ulcers and inflammation
Prolapse of the eyeball (in severe cases)

Their eyes may swell more easily and need daily attention to keep them moist and clean. Owners should be extra cautious about roughhousing, sharp objects, or dusty environments.

Genetic Conditions Linked to Eye Problems

Other breeds may inherit eye conditions like:

Entropion (inward-turning eyelids)
Ectropion (outward-turning eyelids)
Cherry eye (prolapsed third eyelid gland)

Each of these can lead to chronic irritation, inflammation, and yes, eye swelling. Recognizing breed-specific risks helps you stay one step ahead in your dog’s care routine.

Diagnosing the Cause of Eye Swelling

Importance of a Veterinary Exam

When your dog develops a swollen eye, guessing the cause isn’t just ineffective—it can be dangerous. The eye is a sensitive, complex structure, and problems can escalate rapidly. This is where a professional veterinary exam becomes essential. While it might be tempting to look up symptoms online or try home remedies, only a trained vet can pinpoint the exact reason for the swelling and decide the best course of action.

Here’s what to expect during a vet visit:

Visual inspection: The vet will examine the eye for signs of trauma, discharge, redness, or abnormalities.
Detailed history: You’ll be asked questions about when the swelling started, any other symptoms, recent activities, diet, or exposure to potential irritants.
Light and pupil tests: These assess whether the eye is responding to light normally and if there’s pain.
Intraocular pressure test: A tonometer may be used to check for glaucoma.
Fluorescein stain test: This highlights corneal scratches or ulcers.
Eye swabs or cultures: If infection is suspected, the vet might collect a sample for lab analysis.

Sometimes, blood work, X-rays, or ultrasounds might be necessary if a more serious systemic illness or tumor is suspected.

Getting a clear diagnosis ensures the right treatment—and fast relief—for your dog. Never assume a swollen eye is “no big deal.”

Tests and Procedures Used

Here are the most common diagnostic procedures your vet may perform:

Schirmer tear test: Measures tear production to diagnose dry eye (KCS).
Ophthalmoscopy: An in-depth look at the retina and optic nerve.
Ultrasound of the eye: Used when tumors or foreign bodies are suspected but not visible.
Cytology: Microscopic examination of eye discharge to identify infectious agents or cancerous cells.

Each of these tests helps narrow down the problem so your vet can act quickly and effectively. The goal isn’t just to treat the symptoms—it’s to address the root cause.

Treatment Options for a Swollen Eye

Medications and Drops

Once the vet determines what’s behind your dog’s swollen eye, treatment can begin. In many cases, non-surgical solutions like medications and eye drops are all that’s needed to resolve the issue.

Here are some of the most common treatments:

Antibiotic drops or ointments: Used for bacterial infections or conjunctivitis.
Steroid drops: Reduce inflammation and swelling, especially in allergic reactions or autoimmune conditions (not suitable if corneal ulcers are present).
Antiviral or antifungal medications: Necessary for viral or fungal eye infections.
Pain relievers: Often prescribed for injuries or conditions like glaucoma.
Lubricating drops: Useful for dry eye or brachycephalic breeds prone to exposed corneas.

Medications are usually prescribed for 1 to 2 weeks, and many vets recommend a follow-up visit to ensure the condition has fully cleared up. You may also be instructed to gently clean your dog’s eye and prevent them from scratching it—an Elizabethan collar (cone) might be necessary.

Surgical Interventions When Needed

Some conditions, especially advanced ones, require surgery. While this may sound scary, many of these procedures are routine and have high success rates.

Common surgical treatments include:

Cherry eye surgery: To reposition a prolapsed third eyelid gland.
Eyelid surgery: To correct entropion, ectropion, or remove tumors.
Enucleation: Complete removal of the eye in cases of untreatable glaucoma, cancer, or trauma.
Foreign body removal: Performed if something is lodged in the eye and cannot be flushed out.

Your vet or a veterinary ophthalmologist will guide you through the process, discuss risks, and offer post-operative care instructions. Most dogs adapt quickly after surgery and enjoy full, pain-free lives.

Home Care Tips and First Aid

Flat lay of contact lens care kit with solution and tweezers on blue backdrop.

Cleaning the Eye Safely

Even after a diagnosis and vet visit, home care plays a vital role in your dog’s recovery. If your dog has a mild irritation or if you’re instructed by your vet, gentle cleaning can help reduce swelling and prevent infection.

Follow these tips:

Use saline solution (available at pharmacies) to rinse the eye. Avoid using contact lens solution unless it’s labeled as plain saline.
Gently wipe away discharge with a soft, damp cloth or sterile gauze.
Don’t touch the eyeball directly—just clean the outer area around the eye.
Wash your hands before and after touching your dog’s eye.

Never use human eye drops unless directed by a vet. Some ingredients can be toxic or make the problem worse.

When to Use a Cold Compress

Cold compresses can help with minor swelling caused by allergies, mild trauma, or insect bites. Wrap a clean towel around a bag of frozen peas or crushed ice, then hold it gently against the swollen area for 5–10 minutes. Repeat up to 3 times a day.

Cold compresses help:

Reduce inflammation
Relieve itching
Ease mild pain

Just be sure your dog tolerates it—some may find it uncomfortable or resist sitting still. If the swelling doesn’t go down in a day or worsens, call your vet.

Preventing Eye Swelling in Dogs

Regular Grooming and Eye Checks

Prevention is better than treatment, especially with something as sensitive as your dog’s eyes. Simple daily habits can prevent many common causes of swelling.

Here’s what helps:

Keep fur trimmed around the eyes to avoid irritation.
Clean tear stains and discharge daily using vet-approved wipes.
Check for redness or swelling during grooming or petting.
Monitor eye response to light to detect early signs of trouble.

Regular grooming appointments and at-home maintenance can prevent buildup of debris, reduce the chance of infections, and make it easier to spot issues early.

Avoiding Common Irritants

Dogs are exposed to a world of eye irritants—dust, pollen, smoke, and more. A few lifestyle adjustments can protect their vision and comfort.

Tips to minimize exposure:

Avoid cigarette smoke and strong cleaning agents.
Limit outdoor time during high pollen seasons.
Close car windows to prevent wind and dust blowing into the eyes.
Use goggles if your dog rides in open vehicles like motorcycles or ATVs.

Also, be mindful of where your dog plays. Tall grass, sandy trails, or chemical-treated lawns can all cause irritation. Prevention takes effort, but it keeps your dog healthy and happy.

When to Seek Immediate Vet Attention

Emergency Signs You Shouldn’t Ignore

Some eye conditions can’t wait. In fact, delays in treatment could cost your dog their vision—or worse. If you ever notice the following symptoms, get to a vet immediately:

Bulging or protruding eye
Sudden blindness or disorientation
Thick yellow or green discharge
Bleeding from the eye
Eye injury from trauma (e.g., hit by a car or bitten by another animal)
Pupil size changes
Severe squinting or inability to open the eye

Trust your instincts. If your dog seems in pain or is behaving unusually, don’t take chances. Fast action can mean the difference between recovery and permanent damage.

Long-Term Eye Health for Dogs

Tips for Maintaining Healthy Vision

Caring for your dog’s eyes doesn’t stop once the swelling goes down. In fact, consistent long-term care is crucial to keeping those expressive, loyal eyes in top shape. Just like humans, dogs are prone to developing eye issues as they age—or even earlier if they’re genetically predisposed.

Here are some habits that go a long way in preserving your dog’s eye health:

Routine eye exams: Annual vet visits should include a close inspection of the eyes. For breeds prone to eye issues, more frequent checks might be necessary.
Daily observation: You know your dog best. A quick look at their eyes during cuddle time can help you notice changes like cloudiness, discharge, or redness before they become serious.
Balanced nutrition: A diet rich in omega-3 fatty acids, antioxidants, and vitamins like A, C, and E can support eye health. Supplements may also help for senior dogs or those with existing conditions.
Protective measures: If your dog spends time outdoors in dusty, sunny, or windy environments, consider canine goggles. They protect against UV rays, debris, and irritants.
Regular grooming: Keep fur trimmed around the eyes and clean tear stains regularly. This minimizes the risk of hair or bacteria irritating the eye.

By adopting these practices, you can reduce the risk of future flare-ups and catch problems early. Healthy eyes are essential for your dog’s quality of life—and their ability to enjoy the world around them.

Conclusion

A swollen eye in your dog isn’t just a minor inconvenience—it’s a warning sign. It could be something as simple as an allergic reaction or as serious as glaucoma or a tumor. Either way, ignoring it or trying to self-diagnose can lead to bigger problems, including infection, chronic pain, or even permanent vision loss.

Understanding the possible causes—whether environmental, infectious, traumatic, or genetic—gives you a head start in recognizing the issue and seeking timely care. Always watch for other symptoms like discharge, squinting, or behavior changes. And don’t hesitate to consult a vet, even if the issue seems minor.

Your dog can’t tell you when their eye hurts. But with attentive care, proactive treatment, and a bit of education, you can protect their sight and ensure they keep exploring the world with bright, happy eyes.

FAQs

1. Can I use human eye drops on my dog?

No, not unless your vet specifically instructs you to. Many human eye drops contain ingredients that are not safe for dogs and could make the issue worse. Always use veterinarian-approved products.

2. How long does it take for a swollen eye to heal in dogs?

It depends on the cause. Minor irritations or allergic reactions can clear up in 1–3 days with proper care. Infections may take 1–2 weeks. More serious conditions like ulcers or glaucoma require long-term or ongoing treatment.

3. Are some dogs more prone to eye issues than others?

Yes. Flat-faced (brachycephalic) breeds like Pugs, Bulldogs, and Shih Tzus are more likely to experience eye injuries, dryness, and swelling. Dogs with long hair around their eyes or certain genetic conditions also have a higher risk.

4. Is a swollen eye always painful for dogs?

Not always, but often. Conditions like trauma, infections, and glaucoma can be very painful, while mild allergic reactions might just cause discomfort or itching. Watch for signs like squinting, head rubbing, or avoidance of touch.

5. Can I treat my dog’s swollen eye at home?

Only if your vet approves it and the cause is minor. For example, saline rinses or cold compresses can help with mild swelling. But if there’s discharge, cloudiness, or signs of pain, you should see a vet immediately. Misdiagnosing or delaying care can lead to serious consequences.

Please don’t forget to leave a review.