Conjunctivitis in Dogs

Understanding Conjunctivitis in Dogs

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Pinkeye. Properly known as conjunctivitis it may be something you have dealt with in the past, as in humans it is a fairly common eye infection. What you may not know is that it is something that often affects dogs as well.

What is conjunctivitis in dogs?

The conjunctivitis found in dogs is similar, but not quite the same, as that found in humans. The conjunctiva is a mucus membrane found in the eye that is there to protect it from debris and damage. It covers the whole eyeball and lines the eyelids as well.

Simply put, conjunctivitis is an infection of that membrane. It can be more complicated in dogs - and cats - than in humans, as they have a third eyelid, and so the infection has a greater area that it can spread to, increasing the pain and irritation a pup feels.

What causes conjunctivitis in dogs?

Eye infection in a bulldog

A 3-year-old Bulldog with a red right eye

Conjunctivitis in dogs can be caused in a number of different ways. 

These include all the following risk factors:

  • A viral infection such as canine distemper virus
  • An allergic reaction to a medication
  • An autoimmune disorder in the eye
  • Blocked tear ducts
  • Unvaccinated puppies with distemper virus
  • An eye injury (especially a scratch)
  • Entropion, a condition in which the eyelids roll inward 
  • A reaction to environmental pollutants like smoke, pollen or dust and dirt
  • Chronic dry eye
  • Ulcers in the eye, including the condition ulcerative keratitis
  • An infection of the eyelash
  • Dangers outside such as thorns from rummaging in bushes
  • Unintended eye injuries from shampoo, scissors, drying and restraint can occur during your dog's grooming

Are certain breeds more susceptible to developing eye conditions?

Yes, and being aware of your pet’s unique risk for certain diseases may allow earlier detection and treatment.

“Allergies are a major cause of conjunctivitis in dogs. Dogs overly sensitive to pollen, dust and mold often rub and paw at their eyes continuously.”

- Dr. Carol Osborne DVM, Chagrin Falls Pet Clinic -

Allergy-prone breeds such as cocker spaniels and bulldogs are a higher risk since they are more sensitive to irritants in the environment, such as pollen or dust. 

Some dog breeds are more prone to developing conjunctivitis secondary to another common to their breed condition. This includes nodular episcleritis in Collie breeds and crosses and plasma cell conjunctivitis in german shepherds.

Young Siberian huskies are susceptible to developing cloudy lenses (cataracts).

Dogs with prominent eyes such as boston terriers, pugs, bulldogs, cockers, cavalier King Charles spaniels, westies, pekingese pups and shih tzus, due to their skull shape, are at increased risk for infections on the surface of their eyes (corneal ulcers). 

Outdoor, sporting and hunting breeds are also at a higher risk due their working outside.

Finally, Terrier breeds are at a higher risk of developing glaucoma after the lenses in their eyes move (lens luxation).

How can I tell if my dog has conjunctivitis?

Dog with irritated red eyes

Pup with irritated red eyes from a common allergen such as dust, pollen or mold.

Although he obviously cannot tell you that his eyes feel itchy and irritated (which they will if he has conjunctivitis) there are a number of signs that a pup may have pink eye. These include the following:

  • Discharge from the eyes, often yellowish or pale green in color
  • Excessive blinking
  • Squinting (sign of discomfort)
  • Swelling of the eyes
  • Redness in the whites of the eyeball
  • Pawing at the eyes
  • Sneezing and coughing
  • Loss of appetite (due to pain)

Many of the symptoms of conjunctivitis can also apply to other infections - especially more serious eye diseases in their early stages - so it is very important that you take your dog to his vet for a check up as soon as possible, both to relieve his pain and irritation and to prevent more serious, long term damage to his eyes from occurring.

How is conjunctivitis in dogs diagnosed?

When your vet examines your dog, they'll look for several things, not just to give a positive diagnosis of conjunctivitis. 

A series of diagnostic tests are used to try to determine the underlying cause.

Your vet will try to determine if the problem is an isolated infection - as it would be if it was caused by an allergic reaction or irritation from environmental irritants - or a secondary sign of a more serious condition.

These other conditions could include glaucoma and ulcerative keratitis, so these need to be ruled out and the overall health of the eyes needs to be examined. 

It is likely that your vet will perform a standard eye exam, a tear production test (known as the Schirmer tear production test) an eye pressure test to rule out glaucoma and a corneal stain test to ensure there is no damage to, or abnormality in, the cornea of the eye itself.

Finally, your vet may perform a thorough exam using slit lamp biomicroscopy, which will definitively diagnose the cause of the conjunctivitis or suggest other causes, such as allergy or infection.

If there is no sign of other disease, and you do not know of any recent trauma, or contact with another infected dog, that may have led to the problem after making a positive diagnosis of conjunctivitis your vet may also order allergy testing, to determine if it is 'something in the air' that led to the infection.

How is conjunctivitis in dogs treated?

Conjunctivitis is very common in both dogs and cats, but the underlying cause and treatment options can vary greatly. 

Simple conjunctivitis treatments

Dogs with simple allergic conjunctivitis can be treated with a topical antihistamine. 

If 'simple conjunctivitis' is diagnosed your pup will be put on a course of antibiotics to clear the infection up. These may be oral, topical or, in some cases, to be given in the form of eye drops. Some pups, if their eyes have become very swollen, may also be given anti-inflammatory medications to address that problem. If they have 'dry eye' they will be given medication to stimulate tear production as well.

When conjunctivitis is not the primary abnormality

A stronger topical anti-inflammatory, specifically a corticosteroid may be used.

If the conjunctivitis is determined to be a secondary symptom of another eye disease, that will then be treated as a separate issue. These treatments will vary depending upon what the diagnosis made is, and may involve visits to and treatment from a veterinary ophthalmologist as well as your regular vet.

Other possible eye infections include: glaucoma, corneal ulceration, intraocular inflammation or an inappropriate tear film in dogs with dry eye.

W​ARNING: It should be noted that there are a lot of articles on the Internet that suggest home treating conjunctivitis in dogs with 'home remedies'. It is not a good idea to try and make use of these in lieu of a visit to your vet. 

Conjunctivitis is an infection and it will not go away on its own. 

By not treating it properly not only will you be forcing your pup to deal with pain and irritation but also risking the long term health of their eyes.

Recovery and Prevention

Most pups recover very well from conjunctivitis itself and in the short time it takes for the antibiotics to do their thing. If an underlying problem caused the infection it is likely that this will still need to be treated on a long term basis, as is the case with, for example, chronic dry eye.

As prevention is always preferable to cure, most pet parents will want to do all that they can to help prevent their dog from developing, or redeveloping, conjunctivitis.

Some things may be obvious. 

If the infection was caused by an allergy, owners will have to take steps to help their dog avoid contact with that allergen. 

If the problem was an airborne irritant, then they should be helped to avoid that.

Paying greater attention to your dogs' general eye health is a must no matter what. This includes making sure that their diet is a balanced one that contains the nutrients needed for good eye health. These include beta-carotene, lutein, Vitamins A and C and, in the opinion of some experts, Omega 3 fatty acids as well.

So, the main takeaway to remember about conjunctivitis? Is that it’s not as simple as pet owners might think. Always get diagnostic testing to either rule out something more pertinent or confirm that the disease can be quickly and easily treated.

This quick informational video by Dr. Aimee Beger summarizes conjunctivitis in dogs: causes, symptoms and treatments.

Share Your Experience: Have a story about conjunctivitis in dogs? Share it with us by leaving a comment below.

If you are concerned about your pet, visit or call your veterinarian – he/she is your best resource to ensure the health and well-being of your dog. This information is for informational purposes only and is not meant as a substitute for the professional advice of, or diagnosis or treatment by, your veterinarian with respect to your pet.

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