Conjunctivitis in Dogs

Causes, Treatment, and Prevention

French bulldog getting an eye exam on vet exam table
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Conjunctivitis in dogs is the inflammation of tissue in a dog's eye. Symptoms of conjunctivitis include rednesseye discharge, and swelling. Conjunctivitis can occur independently or result from a more serious ocular disease. The treatment and prevention depend on the cause of conjunctivitis, but usually, topical anti-inflammatories and antibiotics will resolve the issue. Your vet will perform a thorough exam on your dog's eye to identify the cause of conjunctivitis and treat it accordingly. The prognosis is favorable for dogs diagnosed early and receiving prompt treatment, but the prognosis is more guarded for dogs with underlying issues. Any breed can contract conjunctivitis, but bulldogscocker spaniels, and miniature schnauzers can be more susceptible. 

What is Conjunctivitis in Dogs?

Conjunctivitis, also known as "pink eye," is common in dogs. It results from the inflammation of the conjunctiva, the thin layer of tissue that lines the eyelid. It can affect one or both eyes and may start in one and spread to the other.

Symptoms of Conjunctivitis in Dogs

The symptoms of conjunctivitis are usually identifiable. If your dog's eye looks inflamed and produces colored discharge, visit your vet for a potential conjunctivitis diagnosis.


  • Eye redness
  • Eye discharge
  • Swelling of the eyes
  • Squinting
  • Excessive blinking
  • Rubbing or pawing at the eyes

If your dog has conjunctivitis, it will experience uncomfortable symptoms that, if untreated, may worsen, especially as your dog tries to scratch its itchy eyes. If your dog's eyes look inflamed, red, or oozing, it likely has conjunctivitis. Your dog may also blink excessively and squint. While the symptoms of conjunctivitis are recognizable, a possible underlying cause might not be so obvious. If conjunctivitis symptoms accompany other, seemingly unrelated symptoms, consider a more significant problem as a cause.

Causes of Conjunctivitis

  • Allergies: Conjunctivitis in dogs can be caused by environmental allergens, which may cause a dog's ocular mucus membrane to become irritated and inflamed. Allergens like pollen, mold, and dust are likely to lead to conjunctivitis in your dog. Even if the irritant itself isn't the cause of the conjunctivitis, your dog's scratching at its itchy eyes can cause inflammation secondarily.
  • Virus: Viral infections like canine herpes, canine distemper, and canine influenza can cause conjunctivitis in dogs. Symptoms of conjunctivitis due to a viral infection don't differ from those of any other cause.
  • Bacteria: Bacteria in the eye can cause conjunctivitis. This usually occurs when a dog has a non-ocular bacterial infection such as Streptococcus or Staphylococcus that contacts the eye through another body part.
  • Immune disease: An autoimmune disease can make your dog more susceptible to developing conjunctivitis. Your dog's eye will be more affected by bacteria and allergens with a weakened immune system.
  • Foreign objects: An eye injury in a dog caused by a foreign object can become infected if not treated swiftly. Foreign objects can range from a piece of dirt to a piece of plastic. Not only is the object an irritant, but it may carry harmful bacteria, fungi, viruses, or parasites.
  • Dry eye: Dry eye, a condition in which the tear gland cannot produce the tears necessary to flush debris and bacteria from the eye, can lead to conjunctivitis. Dry eye is among the most common causes of conjunctivitis.
  • Growths: A growth inside the eye that obstructs or irritates the tear duct eye can lead to conjunctivitis.

Diagnosing Conjunctivitis in Dogs

Your vet will perform a thorough ophthalmic exam to diagnose conjunctivitis, beginning by looking for foreign objects or tumors in the eye. Usually, a diagnosis can be made by the outward clinical appearance of the eye, but sometimes, your vet may do additional tests. These include tear tests, stains to look for corneal ulcers or lesions, measurement of intraocular pressure, or a biopsy. The primary goal of the diagnosis is to determine whether the conjunctivitis is developed on its own or if it's the secondary issue of a more severe problem. Your vet will perform more specialized tests if they suspect a different primary cause.


The treatment for conjunctivitis depends on its cause. If a dog's conjunctivitis is a secondary infection, your vet will treat the primary infection in addition to the conjunctivitis. Your vet can usually treat primary conjunctivitis using topical steroids, antibiotics, or anti-inflammatories. If your dog's infection is related to dry eye, it may be prescribed tear stimulants. Sometimes, if an eyelash or eyelid abnormality occurs, your dog will require surgery. If a virus is causing your dog's pink eye, your vet may prescribe an anti-viral medication. If a more serious ocular disease is the cause of conjunctivitis, your vet will take appropriate care measures to treat both problems.

Prognosis for Dogs With Conjunctivitis

Most dogs with conjunctivitis have a favorable prognosis, especially if there isn't something more serious causing the infection. Eye drops and topical medications are very effective. As always, early treatment is key to a swift recovery. Dogs with untreated conjunctivitis may suffer permanent ocular damage.

How to Prevent Conjunctivitis

There are measures you can take to help prevent conjunctivitis in your dog. Still, you cannot avoid some forms of conjunctivitis. If you suspect that environmental allergies are causing your dog's pink eye, limit contact with irritants. You should also be mindful of your dog's contact with matter that may cause eye trauma. Additionally, make sure your dog is fully vaccinated against viruses that lead to conjunctivitis.

The best thing you can do to curb conjunctivitis is to pay close attention to the health of your dog's eyes and take it to the vet as soon as you suspect an issue.

  • Is it normal for my dog to tear?

    Some tearing is normal and a sign of healthy eye function, but it is likely infected if your dog's eye is secreting colored, thick discharge.

  • Is there a bigger health problem causing my dog's conjunctivitis?

    Your vet will diagnose your dog's conjunctivitis and run tests to ensure there isn't a more significant, serious cause of the infection.

  • Can I treat my dog's conjunctivitis at home?

    There are over-the-counter treatments you can get to relieve some of your dog's discomfort, but it's essential to visit your vet. Because there may be an underlying, primary cause, a proper diagnosis is imperative.

Article Sources
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  1. Conjunctivitis in Dogs. VCA Hospitals.

  2. Ledbetter, E. C. et al. Virologic Survey of Dogs With Naturally Acquired Idiopathic Conjunctivitis. Journal of the American Veterinary Medical Association235(8), 954–959, 2009. doi:0.2460/javma.235.8.954