When your beloved dog starts pawing at their eye, squinting in discomfort, or developing unusual discharge, it's natural to feel concerned—and you should be. Eye infections in dogs are more common than many pet owners realize, affecting both indoor and outdoor companions, including emotional support animals, and can range from minor irritations to serious conditions that threaten your dog's vision if left untreated.

The good news is that most canine eye infections are highly treatable when caught early and managed properly. Whether you're dealing with bacterial conjunctivitis, a corneal scratch, or dry eye syndrome, understanding the warning signs, causes, and treatment options can make all the difference in preserving your dog's eyesight and comfort. This comprehensive guide will walk you through everything you need to know about recognizing, treating, and preventing eye infections in dogs—but remember, as with any health concern, consulting your veterinarian promptly is always the best first step toward getting your furry friend back to their happy, healthy self.

Whether you have an indoor or outdoor dog, or even an emotional support animal, it can be susceptible to many diseases, including eye infections. There are several reasons why your dog might develop an eye infection. And while this might be scary for any pet owner, these infections are treatable with quick action and proper care.

As with any disease or infection, it is best to consult a veterinarian as soon as possible before attempting at-home care.

What Causes Eye Infection in Dogs?

The cause of eye infections in dogs differs in various cases. There are many different causes, and they can vary depending on your breed, size, whether they are an outdoor or inside dog, and what other animals they are around.

• Fungus
• Bacteria such as leptospirosis, Lyme disease, and canine brucellosis.
• Viruses include canine influenza, hepatitis, canine distemper virus, and herpes.
• Parasites
• An injury to the cornea
• Irritants such as chemicals and smoke.
• Foreign bodies in the eye, such as plant material, fur, and debris.
• Eye abnormalities predispose your dog to infections, such as eyelid tumors, an abnormal tear in the eye's film, and inward/outward turning eyelids.

Types of Dog Eye Infections and Related Conditions

• Conjunctivitis - inflammation of the pink tissue that lines the eyelids. Often causes redness, discharge, and squinting.
• Keratitis and corneal ulcers or abrasions - injury or infection of the cornea that can quickly worsen without treatment.
• Uveitis - inflammation inside the eye that can be very painful and threaten vision.
• Dry eye (keratoconjunctivitis sicca or KCS) - inadequate tear production that leads to thick mucus, irritation, and recurrent infections.
• Blepharitis and eyelid infections - swollen, itchy eyelids from bacteria, allergies, or parasites.

Not All Eye Problems Are Infections

Glaucoma, tear duct issues, eyelid or eyelash abnormalities, and tumors can mimic infection signs. All eye problems deserve prompt veterinary evaluation to protect your dog’s vision.

Styes

A dog's eye stye is a painful, red lump that develops on the inner edge of the eyelid. It is transmitted to the eye by Staphylococcal bacteria, often found in the nasal passages and introduced by scratching the nose then touching the eye area. Styes usually look like small, pus-filled pimples and are uncomfortable but not harmful to eyesight.

Apply a warm compress 3 to 4 times daily for 10 to 15 minutes to ease pain and encourage drainage. A chalazion on a dog’s eye is often mistaken for a stye and appears as a firm, round bump from a blocked oil gland. Do not pop or drain any eyelid lump at home.

Stye care tips

• If swelling worsens, pus persists, or lumps recur, see your veterinarian for care and possible drainage.
• Remember not to pop or drain the stye or chalazion on your own. It can lead to further complications and may result in more pain for your dog.

What Are the Signs of a Dog Eye Infection?

There are many ways your ESA dog will alert you that it potentially has an eye infection. It is essential to note that many of these signs do not appear independently but together. Visiting your veterinarian with your dog's ESA letter is necessary if you observe any of the following symptoms:

Discharge From the Eyes

Excessive discharge from the eyes is one of the most apparent signs of an eye infection in a dog. However, not all discharge is the same, and the specific discharge can give better insight into what type of infection it is.

Thick and purulent yellowish-green discharge is usually a sign of a bacterial infection, while clear discharge could indicate a viral infection. 

What Discharge Colors Can Mean

• Clear or watery - allergies, irritation, or early infection.
• Yellow or green - bacterial infection is common and needs veterinary care.
• White or gray mucus - possible dry eye (KCS) that requires testing.
• Reddish-brown tear staining - often porphyrins. Cosmetic for many dogs but see your vet if staining increases or is accompanied by other signs.

Pawing at Their Eyes

As eye infections are often painful or very itchy, a dog suffering from it will often paw at its eyes and even drag its face across furniture and floors. Although dogs do this to get relief, this behavior further damages the dog's eyes. 

To prevent this, your veterinarian may prescribe a cone for your emotional support animal to wear while the infection is treated.

Squinting

Squinting and increased eye blinking is usually caused by an infected eye's pain and irritation.

Redness and Swelling

If your dog has an eye infection, its eyes may be more crimson or pink than usual, and the eyelid may be inflamed. Typically, eye infections cause the tissue surrounding the eye to swell, making the eyelid appear droopy or swollen.

Acute vs Chronic Signs and the Third Eyelid

• Acute signs - sudden squinting, rubbing, light sensitivity, or a new colored discharge can indicate injury or infection that needs prompt evaluation.
• Chronic signs - ongoing mild redness, thick mucus, or recurrent discharge can suggest dry eye or eyelid problems.
• Third eyelid showing - a prominent inner eyelid that partially covers the eye is a common red flag that your dog is uncomfortable or has ocular disease.

Infection vs Allergies

As a rule of thumb, one eye is more likely with infection or trauma, while both eyes can point toward allergies or irritation. Your vet will confirm the cause.

• Common allergy clues - clear watery discharge, frequent itchiness, sneezing, seasonal patterns, and known triggers like pollen, dust, or recent swimming in ponds.
• Infection clues - yellow or green discharge, significant redness, squinting, and pain.

When to See a Vet vs Emergency

• Call your vet within 24 hours if - redness lasts more than a day, colored discharge appears, your dog is squinting or rubbing the eye, or the third eyelid is visible.
• Seek emergency care now if - chemical exposure, any trauma, the eye is bulging, you see a blue or white haze, your dog shows severe pain, or there is sudden vision loss.

How Vets Diagnose Dog Eye Infections

As of 2025, veterinarians typically combine a focused eye exam with simple in-clinic tests to pinpoint the problem and protect vision.

Common Diagnostic Tests

• Schirmer tear test - measures tear production to identify dry eye (KCS).
• Fluorescein stain - detects corneal scratches or ulcers that can worsen quickly without treatment.
• Tonometry - checks eye pressure to screen for glaucoma and evaluate uveitis.
• Eyelid and eyelash exam - looks for entropion, ectropion, masses, or stray lashes that irritate the cornea.

What Your Vet May Ask

• Onset and duration of signs
• Discharge color and whether one or both eyes are affected
• Any recent trauma, foreign body exposure, shampoo or chemical exposure
• Recent swimming or dusty, windy hikes
• Breed and prior eye issues

Brief Example

Example: a dog with sudden squinting and green discharge tested positive for a corneal ulcer on fluorescein stain and improved after antibiotic drops and a cone, with a recheck 3 to 5 days later to confirm healing.

How to Treat Dog Eye Infection

The treatment the veterinarian prescribes for your dog will depend on the cause of the infection. Your vet may recommend an ointment or eyedrops to ease the itchiness, treat the underlying condition and promote healing.

The vet may also prescribe oral medication and injections to combat infections deeper in the eye. There are some ways to provide loving care at home to help aid in your dog's recovery so it can quickly return to the best of health. 

• Keep the area around the eye clean - Dampen a soft, clean towel with warm water, and gently clean off any discharge build-up around your dog's eyes. Please do not use any chemicals or touch their eyes. Contact your vet if the discharge is not easily removable or if there is debris in the dog's eye.
• Use a cone - A dog cone gives the prescribed treatment a chance to work, as your dog won't be able to cause any more damage to the eye. We recommend discussing alternatives with your vet if your dog has trouble adjusting to the cone.
• Eyedrops - If the vet has prescribed eyedrops for your emotional support animal, gently tilt your dog's head back, and squeeze the drops to the upper part of the eye with your hand resting on the dog's head.
• Ointment - To apply the cream, pull down your dog's lower lid and create a pocket for the medication. Rest your hand on the dog's head, and squeeze the ointment into the eye. Open and close the eye gently to spread the cream evenly.

Corneal Ulcer or Abrasion

Topical antibiotics and pain control are common, with a protective cone to prevent rubbing. Avoid steroid eye drops unless your veterinarian prescribes them, because steroids can worsen ulcers according to veterinary ophthalmology guidelines. Rechecks are typically needed to ensure the cornea is healing.

Dry Eye (KCS)

Tear stimulants such as cyclosporine or tacrolimus plus lubricating artificial tears are mainstays. This is often long-term management with periodic tear testing.

Eyelid or Eyelash Abnormalities

Surgical correction may be recommended for entropion, ectropion, or masses. Lubrication can protect the cornea until surgery is performed.

Allergy-Related Inflammation

Your vet may recommend antihistamines or anti-inflammatory medications and trigger control. Address environmental factors like pollen, dust, or grooming products that irritate the eyes.

Foreign Body

Have debris removed by your veterinarian. Do not probe the eye at home. Follow with prescribed drops or ointments as directed.

Home Care Do's and Don'ts

Do

• Flush gently with sterile saline or lukewarm water if loose debris is visible.
• Use the cone consistently so the eye can heal.
• Follow dosing schedules and complete all medications.
• Wash your hands before and after medicating the eye.

Don't

• Do not use human eye drops or leftover pet medications without veterinary guidance.
• Do not skip rechecks if your vet recommends them.
• Do not stop medications early even if the eye looks better.

Dosing and Administration Tips

1. Have everything ready, then calmly approach your dog from the side.
2. Rest your hand on your dog’s head for stability.
3. For drops, aim for the upper part of the eye so the drop can spread as your dog blinks.
4. For ointment, create a small pocket by gently pulling down the lower lid and apply a thin ribbon.
5. Allow several minutes between different medications so each can absorb.
6. Plan a recheck based on your veterinarian’s timeline, often within 3 to 7 days for ulcers or moderate infections.

Keeping Your Dog's Eyes Healthy

Your dog's eyesight is priceless, and you can avoid eye infections with the appropriate care. If your ESA dog has long hair, you should first clip the hair around its eyes to prevent irritation. Hold blunt-tip scissors parallel to your dog's eyes and wait until they are still and calm before you start trimming.

You must also routinely clean your dog's eyes with a warm cloth. Wipe the area around the eye gently and avoid wiping the eye itself. Routine eye care is the key to a happy and healthy pup. Also, be sure to take note of any changes to your pup's eye and schedule an appointment with your vet if you notice any alarming changes.

Visit Pettable's blog for more information on pet care, ESA certification, and other valuable resources.

Practical Prevention Tips

• Do not let your dog hang its head out of moving car windows where debris can strike the eye.
• Trim bushes at home and avoid thorny brush on walks to reduce scratches.
• Consider dog goggles for hiking, biking, sandy or windy conditions.
• On windy days, ask your vet about using lubricating artificial tears before and after walks.
• Keep facial hair and tear-stained fur clean and short to limit irritation.
• Brachycephalic breeds with prominent eyes need closer monitoring and quicker vet checks at any sign of squinting or discharge.

Medically reviewed by a licensed veterinarian in 2025.