What causes itchy eyes in pets?

Estimated Reading Time 6 minutes
What causes itchy eyes in pets?

Itchy eyes can be a source of discomfort for your pet. To find relief, your dog or cat may scratch at his eye or rub his face along the furniture or the ground. These behaviors can eventually lead to injury and could compromise your pet’s ability to see. Keep reading to learn how to recognize some of the common causes of itchy eyes and how to help your pet.

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Common Causes of Itchy Eyes in Pets

Many conditions cause itchy eyes in dogs and cats. These include the following:

Foreign Objects

Any foreign object that gets into your dog’s eyes can cause irritation and redness. Your pet may try to get rid of the foreign object by pawing at his eyes. There may also be increased tearing.

If flushing your dog’s eyes with a sterile eyewash fails to dislodge the foreign body, you should seek veterinary attention as soon as possible. The foreign body may irritate and damage the cornea, leading to the formation of a corneal ulcer. Your pet may also injure the cornea and other sensitive eye tissues by pawing or rubbing at the eye.


Also called ‘Pink Eye’, conjunctivitis in pets may affect one or both eyes. Pink Eye is characterized by swelling and redness of the conjunctiva or the membranes that line the eyes and the eyelids.

Many cases of conjunctivitis in pets are secondary to a primary issue. The condition could be caused by a viral or bacterial infection, but it can also be a result of non-infectious causes such as allergies, injury, or irritation. The eye discharge can be clean and runny or pus-like in color. If your pet’s conjunctivitis is accompanied by squinting, cloudiness of the eyes, vomiting, diarrhea, jaundice, and lethargy, get him to the vet immediately. Early medical intervention is needed, or it can lead to blindness, especially if it’s caused by a more serious condition.


Pets can be hypersensitive to various allergens in their immediate environment. Allergens can be airborne and inhaled by pets. Common airborne allergens include mold, dust, pollen, strong-smelling odors, dust mites, and cigarette smoke. Allergy reactions could also occur as a result of flea bites, contact allergens, or food allergies.

One of the prominent symptoms of allergies in pets is itchy eyes. Persistent scratching, pawing, and rubbing of the eyes and the area around them can lead to injury and hair loss around the eyes and muzzle. Your pet’s eyes may also appear watery and reddish. Compared to eye infections, allergies cause watery eye discharge, while an infection is usually associated with a pus-like discharge. Dog with an eye infection may also experience photosensitivity (light sensitivity).


Entropion is an abnormality that causes the eyelid to roll inward. This can result in irritation of the eyes by the hairs on the eyelid. The eyes of affected pets appear reddish and there is increased tearing. The dog may be squinting, or the eye is held closed.

Entropion could cause permanent scarring of the cornea, thus prompt veterinary attention is needed. There is a long list of canine breeds that are predisposed to developing entropion including the Bulldog, Akita, Miniature Poodles, Rottweiler, Shih Tzu, and Pekingese to name a few.

Keratoconjunctivitis Sicca (KCS)

Also called ‘dry eye’, Keratoconjunctivitis Sicca (KCS) is characterized by inadequate tear production that leads to irritation of the cornea and surrounding tissues. KCS in pets is thought to have a genetic factor, although a dog of any breed, gender, or age can be affected. Dog breeds that have higher risks of developing KCS include the Pug, Lhasa Apso, Boston Terrier, and Shih Tzu.

The most common causes of KCS in pets include canine distemper, hypothyroidism, certain medications, and even immune disorders that cause damage to the tear glands. A history of Cherry Eye (prolapse of the nictitating membrane) treatment has also been recognized as an important predisposing factor.

Untreated, dry eye can lead to increased eye discharge, development of corneal ulcers, pain, and discomfort. A Schirmer Tear Test is usually performed by your vet to determine if it’s KCS.


Glaucoma is a serious eye problem that is caused by fluid buildup leading to increased pressure within the eye (also called intraocular pressure). Without prompt medical intervention, the pressure can damage the optic nerve and eventually cause blindness. The signs of glaucoma include swollen eyes, redness, pain, and receding eyeballs. The dog’s eyes have a cloudy appearance and the pupils are dilated and unresponsive. Vision problems are also present.

Corneal Ulcer

There are many causes of corneal ulcers in pets. These include chemical burns, scratches that are self-inflicted or from fighting with other animals, trauma or injury, and constant rubbing of the eyes. Minor eye injuries can lead to complications if secondary infection sets in.

Affected pets experience excessive tearing and blinking, redness and/or swelling around the eye, and pawing or rubbing of the affected eye. Although it can affect any dog breed, dogs with bulging eyes or those with chronic dry eye problems are more at risk. As a genetic condition, corneal ulcers usually develop in middle-aged or senior dogs. Corneal ulcers can easily be diagnosed with a Fluorescein Test. Untreated cases of corneal ulcers can eventually lead to vision loss. Removal of the eye may be indicated in some rare cases.


Pets with blepharitis have inflamed eyelids. The problem can affect one or both eyes. Affected dogs have red, swollen, and itchy eyelids. They may squint and blepharospasm (spasmodic blinking) may be present. The discomfort causes a dog or cat to scratch and rub at their face or eyelids. This can lead to trauma of the surrounding tissues. Eye discharge can present and may be clear, mucoid, or purulent.

Without proper treatment, dry crusts and pimple-like growths may develop on the skin of the eyelids. The inflammation may spread to the tear glands which can also become swollen. In more severe cases, conjunctivitis and keratitis (corneal inflammation) may be present.

The causes of blepharitis can range from congenital conditions to allergies to tumors to infections. Any condition that irritates the eyelids can pave the way for blepharitis.

What to Do If Your Pet Keeps Scratching His Eyes

If your pet persistently scratches at his eyes, you should have him checked by your vet. Avoid administering any over-the-counter medication or home remedies to your pet’s eye as this could lead to irreversible damage and blindness.

Treating Your Pet’s Itchy Eyes

Your pet will first undergo a thorough ophthalmic exam to determine why his eyes are itchy. Depending on the results of the initial exam, your vet may recommend some tests to arrive at a definite diagnosis. There is a need to identify the underlying cause so the appropriate treatment and/or procedure can be performed.

Some eye conditions need prompt and intensive medical attention. Some problems, like entropion, will need surgery to correct the abnormality.

Your vet may find it necessary to refer you to a canine ophthalmologist if your pet’s eye problem is severe and needs more specialized treatment.

Read more:

First Aid for Your Pet’s Eye

Giving Your Pet Eye Medication: Step-by-Step Instructions

10 Facts About Your Dog’s Eyes

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Published: 8/24/2021
Last updated: 8/27/2021

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