Conjunctivitis is one of the most common eye problems in dogs, and it won’t be surprising if your best friend has it. It’s also known as pink eye, and it happens when the conjunctiva, the thin layer that spans the white part of the eyeball, gets inflamed.
Key Takeaways
Conjunctivitis is the inflammation of the conjunctiva, the thin layer that spans the white part of the dog’s eyes.
It’s generally caused by infectious pathogens and non-infectious causes, including foreign bodies and trauma, allergens and irritants, and several eye conditions.
Pink eye is diagnosed through an ocular exam and several specialized tests. It’s treated with medication and supportive care.
How Do You Know if Your Dog Has Conjunctivitis?
It can be quite straightforward to tell. Here are the common symptoms our veterinarians observe in dogs with pink eye.
Redness and Swelling. Canine conjunctivitis causes a visibly red appearance due to the inflammation and increased blood flow to the area. Swelling may also appear around the eyes.
Discharge from the Eye. Depending on the cause of conjunctivitis, a dog’s eyes can have discharge. Clear tearing is often from allergies and irritants, while green or yellow mucus suggests a bacterial infection.
Crusting Around the Eye. Crust can form around the eyes when the discharge dries up. These can cause increased irritation and make it harder for dogs to open their eyes.
Squinting or Excessive Blinking. Dogs with conjunctivitis will start to squint and blink more frequently in response to the discomfort.
Pawing at the Eye. In addition to frequent squinting, conjunctivitis can cause dogs to paw at their eyes in an attempt to relieve discomfort. However, this can worsen the issue and cause more damage.
Sensitivity to Light. If your dog has conjunctivitis, you might notice them trying to avoid rooms with bright light. Some dogs may even start hiding.
What Causes Conjunctivitis in Dogs?
Pink eye in dogs can be caused by infectious pathogens and non-infectious causes such as foreign bodies, trauma, environmental irritants, and several eye conditions.
Bacteria
Bacterial conjunctivitis in dogs is most often caused by environmental bacteria such as Staphylococcus, Streptococcus, and Pseudomonas. It often occurs and develops as a secondary infection when the dog’s eye’s natural defenses are compromised.
These bacterial infections can lead to serious clinical signs if untreated.
Viruses
Viruses are a common cause of pink eye in dogs. These infectious agents easily spread between dogs, causing both ocular and respiratory symptoms. Common examples include:
Canine Distemper Virus. CDV is a major cause, often accompanied by other systemic and respiratory symptoms. They are also highly contagious.
Canine Herpesvirus. CHV-1 directly infects the epithelial cells of the conjunctiva, resulting in cellular damage, tissue death, and inflammation.
Canine Adenovirus. Both CAV-1 and CAV-2 can cause conjunctivitis in dogs, often with similar clinical signs.
Allergies and Irritants
Allergens such as pollen, dust, and mold can also be the reasons why your dog has conjunctivitis. Irritants such as smoke and chemicals may also trigger itching and inflammation, which may lead to this eye condition.
Foreign Bodies and Injuries
Foreign material and trauma may also contribute to conjunctival inflammation through direct irritation and damage. When exposed, the eye easily harbors bacteria that cause secondary infections, leading to pink eye.
Even something as small as sand and a few scratches can contribute, even potentially causing corneal ulcers.
Eye Conditions
Certain eye conditions may contribute to conjunctivitis by making the eyes more susceptible to infection. Common examples include:
Eyelid Abnormalities. Conditions such as entropion, ectropion, and eyelid tumors may contribute by creating chronic physical irritation and inflaming the conjunctiva.
Dry Eye. Reduced tear production may allow bacteria, allergens, and debris to cause inflammation and irritation.
Uveitis. Inflammation from uveitis dilates the blood vessels in the sclera, making the eyes appear red.
Glaucoma. Increased intraocular pressure restricts normal blood flow and dilates the blood vessels in the sclera, resulting in a red appearance and significant swelling.
Corneal Ulcers. Physical damage irritates the surface of the eye, resulting in a painful and intense inflammation.
Which Dogs Are at Risk of Pink Eye?
Certain breeds are genetically more susceptible to conjunctivitis due to their eye shape. Brachycephalic dogs such as Pugs, Bulldogs, and Shih Tzus have more exposed eyes, making it easier for allergens or foreign objects to cause pink eye.
Breeds with skin folds are more likely to develop skin infections that may lead to conjunctivitis. Some dogs genetically predisposed to eye conditions may also be at higher risk.
Generally, healthy eyes look white and normal. But if a dog has conjunctivitis, its eyes will look red and swollen. To help protect your dog against conjunctivitis, we’ll tell you everything about it, from its causes to how to treat conjunctivitis in dogs and how it’s prevented.
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