Conjunctivitis in Dogs: Causes, Symptoms, Treatments

Normally, there’s nothing better than gazing into your dog’s eyes and seeing the love reflected there. But if your dog’s eyes are swollen and red, it’s important to take notice. These are signs that you could be dealing with a case of conjunctivitis in dogs.

Conjunctivitis in dogs (also known as dog pink eye) is a common condition. In fact, most dogs are likely to experience an episode of conjunctivitis at some point during their lifespan. However, there are many underlying causes of the condition, and they can range from mild to serious.

To help you provide your pup with the best care possible, here’s what you need to know about conjunctivitis in dogs, what causes it, and how to treat this common dog eye issue effectively. 

Conjunctivitis in Dogs: What is It?

Conjunctivitis in dogs is very similar to conjunctivitis in humans, though the causes and treatments vary.

Conjunctivitis means “inflammation of the conjunctiva.” The conjunctiva is a thin layer of tissue that covers the inside of the eyelids and the surface of the eye. When this layer becomes inflamed, a dog’s eye becomes red, swollen, and uncomfortable.

Conjunctivitis in dogs may or may not be contagious, depending on what’s causing it.

When a virus or bacteria causes conjunctivitis, dogs can pass this infectious conjunctivitis along to other dogs. In some cases, a dog may also be able to spread bacterial conjunctivitis to humans.

When dogs get non-infectious conjunctivitis (from things like allergies or dry eye), these cases are not contagious.

Conjunctivitis can occur in any dog of any age. However, some breeds are more likely to develop conjunctivitis than others. These include: 

• Cocker Spaniel
• Hounds
• Labrador Retriever
• Lhasa Apso
• Pekingese
• Poodle
• Pug
• Scottish Terrier
• Shar Pei
• Shih Tzu
• West Highland White Terrier

Causes of Conjunctivitis in Dogs

Determining the cause of a dog’s conjunctivitis plays a key role in effective treatment. Conjunctivitis in dogs can have a wide variety of causes, including: 

• Viral infection – Viruses, like canine herpes virus and canine distemper virus, can cause conjunctivitis. 
• Bacterial infection – Bacterial conjunctivitis in dogs can be classified as primary or secondary. Primary means the infection is caused by the bacterium, itself. Secondary means there’s an underlying cause that makes the eye more susceptible to bacterial infection. 
• Allergies – Environmental allergens, like dust and pollen, can trigger conjunctivitis. 
• Airborne irritants – Substances that aggravate the surface of the eye, like smoke and perfumes, can cause conjunctivitis. 
• Corneal ulcer – Trauma or chemical irritants can damage the surface of the eye, resulting in conjunctivitis.
• Dry eye – Dogs with keratoconjunctivitis sicca (KCS or dry eye) do not make enough tears to keep the eye lubricated. The lack of a healthy tear film leads to conjunctivitis. 
• Glaucoma – Increased pressure within the eye leads to inflammation and conjunctivitis. 
• Tumor of the eye or eyelid – Tumors that irritate the eye often cause conjunctivitis.
• Immune-mediated – Autoimmune conditions can lead to inflammation of the eye. 

It’s important to note that this list is not exhaustive. Anything that irritates the eyes or eyelids can potentially cause conjunctivitis.   

Conjunctivitis in Dogs Symptoms

Detecting the signs of conjunctivitis in dogs plays a key role in getting your pet the treatment they need. Here’s what to watch out for.

The primary symptom of conjunctivitis in dogs is swelling and inflammation of the tissues surrounding the eye.

You may notice swelling of your dog’s third eyelid, also known as the nictitating membrane. This is the small pink piece of tissue located in the middle corner of each of your dog’s eyes. The third eyelid may be more visible than usual, it may look swollen, or it may become a darker red color.  

Signs of conjunctivitis in dogs may affect one or both eyes. In addition to red and swollen eyes, symptoms may include:

• Dog with red eyes
• Swollen eyes
• Increased dog eye discharge (clear, yellow, or green)
• Squinting
• Frequent blinking
• Pawing at the face or eye(s)

If your dog has very mild conjunctivitis, it may be okay to monitor your dog at home for 24 hours. Mild signs of conjunctivitis can occur with exposure to dust, perfumes, or other irritants, and they may resolve with time.

However, you know your dog best. If your dog is uncomfortable or you notice pronounced clinical signs, seek veterinary care as soon as possible. 

If your dog’s signs are mild, but they do not resolve within 24 hours, this also warrants a trip to the veterinarian. Seeking veterinary care early reduces the risk of permanent damage to the eye(s). Permanent damage can lead to blindness, so it’s important to always take eye problems seriously in your dog. 

Diagnosing Canine Conjunctivitis

Your veterinarian can diagnose conjunctivitis by carefully examining your dog’s conjunctiva for signs of redness or inflammation.

Effective treatment, however, depends on what’s causing your dog’s conjunctivitis. So your vet will likely recommend further testing to identify the cause. 

Common tests for conjunctivitis include: 

• Fluorescein stain – This test diagnoses corneal ulcers. A fluorescent stain is applied to your dog’s eye. This stain sticks to corneal ulcers, highlighting the lesion. 
• Schirmer tear test – This tests your dog’s tear production, looking for dry eye or KCS. 
• Tonometry – This test assesses your dog’s eye pressure, looking for glaucoma. 

Your vet may also recommend other tests, depending on your dog’s clinical signs. 

Dog Conjunctivitis Treatment Options

Dog conjunctivitis medicine usually comes in the form of an eye drop or eye ointment. However, there is no one-size-fits-all conjunctivitis cure for dogs.

The best medication for your dog will depend on the underlying cause of the conjunctivitis. Here are some examples:

• For conjunctivitis due to bacterial infections and corneal ulcers, vets often prescribe antibiotic eye drops as a dog pink eye treatment.
• For dry eye (KCS) and allergic conjunctivitis in dogs, vets recommend steroids or anti-inflammatory medication as a treatment plan.
• Conjunctivitis caused by glaucoma requires medication to reduce the pressure within the eye.
• If your dog has a tumor causing conjunctivitis, your vet may recommend surgical removal of the tumor.

As a general rule, never give your dog an over-the-counter treatment for conjunctivitis without your vet’s approval. The same applies to any dog conjunctivitis home treatment or remedy. Always check with your vet first.

Also, don’t use old medications or dog eye drops to treat your dog’s current problem. The wrong medication can make your dog’s conjunctivitis worse. For example, treating a corneal ulcer with a steroid may lead to rapid and severe worsening, potentially causing permanent damage. 

How to Prevent Conjunctivitis in Dogs

To keep your dog’s eyes healthy and reduce the risk of conjunctivitis, take these steps: 

• Keep vaccinations current to reduce the risk of viral conjunctivitis.
• Keep your dog away from other dogs with conjunctivitis.
• Minimize exposure to airborne irritants, like smoke, dust, and perfume. 
• Avoid getting shampoo in your dog’s eyes during bathtime. 
• Keep your dog’s facial hair neatly trimmed and groomed. 
• Monitor your dog during playtime to reduce injury risk. 

Unfortunately, not all cases of conjunctivitis are preventable. Even if you do everything you can to prevent conjunctivitis, your dog may still develop this condition. 

FAQs About Dog Pink Eye

Do dogs get pink eye?

Yes, dogs are at risk of pink eye, also known as conjunctivitis. There are many causes of pink eye in dogs, including viral infections, bacterial infections, trauma, allergies, and others. 

Is conjunctivitis contagious in dogs?

Some cases of dog conjunctivitis are caused by viral or bacterial infections. These forms of conjunctivitis can be contagious. However, there are many other causes of conjunctivitis that are not contagious. 

Can dogs get pink eye from humans?

Some cases of human pink eye can be spread to dogs. If you have pink eye, wash your hands frequently and especially before handling your dog. 

Can you get pink eye from a dog?

Pink eye that is caused by a bacterial infection can potentially spread from dogs to humans. Fortunately, bacterial conjunctivitis is relatively uncommon in dogs, making dog-to-human spread of pink eye relatively rare. 

How long does conjunctivitis last in dogs?

The duration of conjunctivitis will depend on its underlying cause. Some cases resolve quickly with treatment, while others may be chronic (long-lasting) in nature. Once your veterinarian determines the underlying cause of your dog’s conjunctivitis, they will be able to provide a prognosis.