Dog: Conjunctivitis

General information

Other common/scientific names: bacterial conjunctivitis, allergic conjunctivitis, inflamed eye, red eye

The conjunctiva is the lining of the inner surface of the eyelid and the exposed surface of the eyeball. The conjunctiva helps to keep the eye moist and protects the eye from infection. A conjunctivitis is the inflammation of the conjunctiva.

Abb. GGT8QLF2: Schematic illustration of the eye, side view.
The conjunctiva is colored in red and the cornea in gray.


There are several causes of conjunctivitis in the dog. Many times, a conjunctivitis is caused by an underlying systemic disease. It is important that the primary condition or cause of the conjunctivitis is identified.

Causes include:

Follicular conjunctivitis is a specific type of conjunctivitis which affects the follicles on the inner surface of the third eyelid (nictitating membrane) and occurs more frequently in young dogs. The third eyelid becomes thickened with a cobblestone appearance. It is thought to be associated with allergies or environmental irritants.

Cardinal symptom

Red eye


Clinical signs of conjunctivitis include reddening and swelling of the conjunctiva. A clear or cloudy discharge may be seen from the eyes. The eyes may itch causing the dog to rub at his eyes. The dog may show signs of discomfort by keeping the eyelids closed or squinting.


Conjunctivitis is diagnosed by physical examination and clinical signs. Testing to determine the underlying cause can include a conjunctival scraping where cells are obtained from the conjunctiva and examined under a microscope. A biopsy of the conjunctiva may also be performed. In chronic cases of conjunctivitis, a culture and sensitivity test may be obtained to determine the exact infection and appropriate medication. If the dog is suspected of having a systemic disease, other laboratory tests may be necessary.


Eye ointments and/or drops containing antibiotics and/or anti-inflammatories are used to treat conjunctivitis. Oral antibiotics and pain medications may be necessary in severe cases. Any other disease conditions will also need to be treated with appropriate medications.

Abb. GFT8WKO4: Applying eye ointment.
This is a photograph of applying eye ointment to a dog’s eye. Care should be taken not to touch the tip of the ointment tube to the eye. Place your hand on the dog’s face, under the eye to steady your hand if the dog moves and prevent touching the eye.

Abb. GFT8ZHKA: Applying eye drops.
This is a photograph of applying eye drops to a dog’s eye. The dog’s head should be tipped upward to allow the drops to fall into the eye. Place your hand on the dog’s face, under the eye to steady your hand if the dog moves and prevent touching the eye.


The prognosis is usually good for conjunctivitis. However, if an underlying disease is not diagnosed or treated, conjunctivitis can recur and become a frustrating condition causing chronic discomfort to the dog.


It is important to administer all medications as recommended by your veterinarian. If you have difficulty applying eye medications to your dog, consult your veterinarian.

Update version: 4/24/2014, © Copyright by
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