Why Are My Dog's Eyes Red?

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"Why are my dog's eyes red?" If you're asking, it might be time for a visit to the veterinarian. Red eyes usually indicate an underlying health problem — and the sooner it's treated, the better.

Read on to learn common causes of red eyes in dogs, what other signs to look out for and how your vet might treat your dog's eyes.

Why Are My Dog's Eyes Red?

Have you noticed that your dog's eyes appear bloodshot? Your dog's eyes could be red for a number of reasons. Here are some of the most common causes:


If a foreign object, such as dirt, dust, grass or hair gets in your dog's eye, it can cause irritation and redness. Cleaning sprays and perfume can also irritate your dog's eyes.

Signs of irritation:

  • Redness
  • Tears or watery discharge
  • Itchy eyes (expressed by pawing at their eyes or rubbing their face)

Treatment: You should contact your veterinarian first before any applying any treatment. They may suggest to gently wash out your dog's eyes with lukewarm water. Wait an hour or two to see whether the redness clears up.


Just like people, dogs can have allergies, too. They can have seasonal allergies and food allergies, as well as allergic reactions to dust, mold, household cleaners and other environmental allergens. Any of these allergies can cause a dog's eyes to turn bloodshot, says the American Kennel Club.

Signs of Allergies:

  • Redness
  • Tears or watery discharge
  • Itchiness
  • Licking and scratching
  • Sneezing
  • Red or inflamed skin
  • Hair loss

Treatment: Don't give your dog over-the-counter allergy medicine or eye drops without first consulting your veterinarian. Proper treatment depends on your dog's specific allergy, which your vet will determine by examining your dog and running tests. In some cases, pinpointing allergens can be a long process, especially if your vet suspects a food allergy (12-week food trials are required to properly diagnose food allergies).

Pink Eye

Pink eye, the common name for conjunctivitis, comes in two forms: infectious and non-infectious. Infectious pink eye is caused by a virus or bacterial infection, while the non-infectious type is generally caused by allergies, irritation, injury, a congenital condition or an illness such as distemper.

Signs of Pink Eye:

  • Red or puffy eyes
  • Itchy eyes
  • Eye discharge
  • Eyelids sticking together, squinting
  • Swelling of the eyelid lining (conjunctiva)

Treatment: Whether or not your dog's case of pink eye is infectious, it needs to be checked out and treated by a vet. They'll determine whether it's the contagious type before determining and treating an underlying cause. Infectious pink eye must be treated with antibacterial or antifungal medicine. Your vet may also give you anti-inflammatory medicine to administer to your dog.

Dry Eye

Another issue that might cause you to wonder why your dog's eyes are red is dry eye, the common term for keratoconjunctivitis sicca (KCS). This condition occurs when the tear glands don't produce enough moisture, causing the tissues of the eye to dry out, says Cuteness. Dry eye can be a result of eye trauma, an underlying health condition or a corneal ulcer.

Signs of Dry Eye:

  • Redness
  • Itchy, painful eyes
  • Thick discharge

Treatment: Your vet will conduct a test to assess the level of moisture your dog's tear glands are producing. They may also check for corneal ulcers. Dogs with dry eye are commonly prescribed eye drops to keep their eyes moist. You'll need to clean their eyes on a regular basis. While dry eye sometimes clears up on its own, it can also be chronic and require lifelong treatment.


Glaucoma is a painful condition caused by fluid buildup that creates swelling and pressure, leading to damage of the optic nerve. If left untreated, glaucoma can lead to blindness.

Signs of Glaucoma:

  • Redness
  • Pain
  • Swollen eyes
  • Receding eyeballs
  • Cloudy appearance
  • Dilated and unresponsive pupils
  • Poor vision

Treatment: If your dog shows signs of glaucoma, bring them to the vet immediately. If you manage to catch the condition early enough, there's a better chance that topical medicine or laser surgery will be effective and that your dog's vision can be saved, says Cuteness. In more severe cases, surgery may be required to relieve pain caused by fluid buildup and pressure. In the most severe cases, surgical removal of one or both eyes may be required.

Side portrait of a shepherd mix with eye closed sitting outdoors.

In addition to the causes listed above, red eyes in dogs can be a sign of an illness, such as distemper, or a chronic health condition like diabetes or hyperthyroidism. Red eyes can also indicate a tumor or certain types of cancer. Some dog breeds are more prone to eye problems than others, says Rover.com. This includes flat-faced breeds like pugs and bulldogs, as well as long-haired breeds whose hair can irritate or damage their eyes. Dogs also become more prone to eye problems and underlying health conditions that can cause eye redness as they age.

How to Help Your Dog and When to Call the Vet

When you first notice your dog's red or itchy eyes, you can wait a couple of hours to see if they clear up on their own. If your dog allows it you can check their eyes and around their eyelids to see if there is anything in it that might be causing the problem. For minor irritations like a loose hair, a lukewarm wet paper towel can do the trick for cleaning around the eyelids. If that doesn't clear up the red eye, call your vet to ask for guidance. If allergies are suspected, your vet might give the go-ahead to give your dog an over-the-counter antihistamine. They can also let you know whether you should bring in your dog for an examination.

Visiting the Vet: What to Expect

When you take your dog to the vet to have their red eyes examined, your vet will likely ask about your pet's recent activity, daily habits and health history. They'll conduct an eye exam and may draw blood to check for underlying health conditions. If allergies are suspected, the vet may ask about your dog's environment, including whether or not you someone in your household smokes, the household cleaners you use and the food you feed your dog. With your cooperation, your vet will be better able to determine the source of the redness, provide appropriate treatment and give you instructions on how to care for your pooch at home.

Dogs are precious and so is their eyesight. If you're curious as to the reason why your dog's eyes are red, it's best to contact your vet.

Contributor Bio

Jean Marie Bauhaus

Jean Marie Bauhaus

Jean Marie Bauhaus is a pet parent, pet blogger and novelist from Tulsa, Oklahoma, where she usually writes under the supervision of a lapful of furbabies.