Conjunctivitis in Dogs: Symptoms and Treatment

Painful, red eyes and eye discharge in your dog are understandably concerning to see.  

Unfortunately, these may be signs of an eye condition called conjunctivitis, which develops because of inflammation or infection. There are a variety of causes, ranging from mild to severe.  

Conjunctivitis in dogs is common, but it generally requires treatment by a veterinarian for resolution.  

If you notice your dog’s eye appears red or she’s squinting frequently, contact your veterinarian for guidance.  

The inflammation occurs for a variety of reasons, such as an infection or exposure to an allergen, which causes inflammatory cells within the eye to react. As a result, dogs with conjunctivitis develop concerning symptoms, such as unusual eye discharge, squinting, and eye redness.  

Conjunctivitis is not generally a medical emergency in itself; however, it can become one if appropriate treatment is not given.  

If left untreated, this condition can severely worsen and affect a dog’s vision.  

If your dog is experiencing discomfort and pain, if they are having trouble seeing, or if the eye symptoms are persistent or worsen, contact a veterinarian immediately.  

• Bacterial infection: Normal eye bacteria, such as Staphylococcus, can cause infection when a dog’s immune system is weak, leading to symptoms of conjunctivitis.  

• Allergen: Dogs with seasonal allergies to pollen or dust, for example, can experience eye inflammation.  

• Chemical or toxin exposure: Exposure to chemicals in the environment, such as from smoke, can irritate the eyeball and surrounding structures.   

• Eyelid abnormalities: Dogs with irregularities of their eyelids, such as improper turning of the eyelid or abnormal eyelashes, have an increased risk for conjunctivitis.  

• Tumors: Although rare, tumors that develop on the eyelid or the conjunctiva can cause significant inflammation within the eye.  

• Other eye conditions: Glaucoma and uveitis cause abnormal eye pressure, which can lead to inflammation within the eye.  

Both males and females are equally likely to develop conjunctivitis. While this condition can affect dogs of any age, it is more common in puppies, young adults, and seniors, likely due to weaker immune systems.  

Certain breeds, such as the Cavalier King Charles Spaniel, Pugs, German Shepherds, and Border Collies, are at an increased risk of conjunctivitis due to genetics.  

A veterinarian will start with a complete physical exam by checking your dog over from nose to tail.  

The eyes will be carefully examined visually and by using an ophthalmoscope, which is a special tool used to identify abnormalities within the eye and surrounding structures. Pet parents can describe any eye discharge they’ve noticed and when symptoms first occurred, giving the veterinarian a complete history.  

If the veterinarian sees symptoms of conjunctivitis on an exam, she will do additional tests to identify the underlying cause, which don’t require any preparation at home by the pet parent. These may include:  

• Schirmer tear test: A small strip of paper is gently placed inside the dog’s eyelid to measure tear production. If the result is abnormally low, lack of tear production may be a contributing factor to the conjunctivitis.  

• Conjunctival swab: For severe cases or those not responding to initial treatment, a swab can be used to collect a sample from the conjunctiva so that it can be processed in a laboratory to identify the bacteria or virus causing the conjunctivitis.  

• Topical ointment. Ointments containing antibiotics and anti-inflammatories, such as Neo-Poly-Dex Ophthalmic Ointment, can improve conjunctivitis in some cases, especially when the underlying cause is a bacterial infection. Terramycin ointment is beneficial if a dog can’t use topical steroids, such as if she has a corneal ulcer.  

• Oral antibiotics. In severe cases or for dogs who do not allow topical administration, an oral antibiotic such as Clavamox can be prescribed.  

• Artificial tears. In some dogs, including those with viral infections, artificial tears can soothe and lubricate the eyes and improve symptoms.  

• Antihistamines. Dogs with allergies can benefit from antihistamines, including hydroxyzine, to reduce their eye symptoms.  

• Oral steroids. To reduce inflammation or treat an underlying immune-mediated disease, prednisone may be prescribed.  

• Other topical medications. Tacrolimus or cyclosporine may be prescribed if underlying immune-mediated conditions affecting the eye are diagnosed. Dorzolamide or atropine sulfate may be given to treat underlying glaucoma or uveitis that can contribute to conjunctivitis. 

Some dogs may benefit from flushing the eye with saline at a veterinarian’s office to remove allergens or foreign objects.  

Surgery may be required to correct eyelid abnormalities or remove tumors that contribute to symptoms of conjunctivitis.  

A veterinarian will advise you on the most suitable treatment option based on your pet’s unique condition. 

Dogs may need to wear a cone while recovering from conjunctivitis, to prevent itching and pawing at their eyes.  

Always follow your veterinarian’s instructions closely when treating your dog at home. 

Maintain regular wellness care, including vaccinations, to protect your dog against viral infections that can cause conjunctivitis.  

Always follow your veterinarian’s instructions for managing any other health conditions your dog may have, because this can reduce their risk of secondarily developing conjunctivitis.