Why Are My Dog’s Eyes Red? Top 10 Reasons

Why Are My Dogs Eyes Red
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Your dog’s eyes are the window to her soul … and her health. You can’t deny the expression in your dog’s eyes if she’s unwell, in pain, or upset. The connection of your dog’s gaze with you is a very powerful way for her to communicate. So when your dog has red eyes, you’ll nearly always notice it very quickly. Here are 10 possible reasons for red dog eyes …

What Causes a Dog’s Red Eyes?

Red eyes in dogs can happen for number of different reasons. Common causes include allergies, an injury, dry eye or a foreign object in the eye. Sometimes red eyes are no real problem. But others need an immediate trip to the vet.

Corneal Ulceration

The cornea is the clear membrane over the front of the eye. If your dog gets a foreign body in her eye or manages to scratch the cornea, it can allow a bacterial infection to attack. The bacteria dissolve the cornea as they grow. This is very painful. You’re likely to see:

  • Severe squinting
  • Mucky discharge
  • Possibly scratching at the eye

Your dog needs veterinary attention for this one! In rare cases, if it’s a really nasty bacteria, an ulcer can perforate your dog’s cornea in as little as 24 to 48 hours! I usually try to avoid antibiotics, but in this case, they can save your dog’s sight. 

Note: If you have a Brachycephalic (flat-faced) breed, her eyes stick out more than is healthy. So her eyelids can’t cover and protect the surface of the eye properly, making her subject to eye trauma. So Brachy breeds often develop ulcers that are chronic. The symptoms may be less obvious.

Eye Trauma

If your dog bangs her eye while playing or chasing, you might see some of these symptoms:

  • Swelling (if it’s a heavy knock) and reddening of the eyelids
  • Reddening of the tissues around the eye
  • Reddening of the sclera (the white part of your dog’s eyeball)
  • Tears flooding the eye right after the incident (especially if the cornea has been scraped or injured)
  • Possible squinting for a short time after a knock (if that doesn’t stop within 30 minutes or so, go to your vet)

If there isn’t any corneal damage, and the knock isn’t too bad, your dog should recover fairly quickly. The eye should return to normal in 12 to 24 hours.

How To Relieve Your Dog’s Red Eye From Trauma

Homeopathic Arnica at a 6C to 30C potency given every 3 hours or so until improved can hasten healing with this sort of injury.

Severe Trauma

If it’s a really severe trauma (think hit by a car, running into a tree at full tilt) you may see severe swelling and bleeding in small patches or large sections of the white of the eye, or even within the eyeball. If you see these signs, please take your dog to the vet as soon as you can.

Environmental Irritants

Smoke, chemicals, artificial fragrances, pesticides and herbicides can all irritate your dog’s eyes, making them red and sore. If your dog swims in the sea or a chlorine pool, that can do the same.

If you’re out and about, red eyes in dogs can be from smog, crop-spraying drift, cigarette smoke and other toxins. This will usually be fairly mild. It should resolve quickly once you move away from the irritant.

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Red Eyes And Dog Allergies

If your dog has atopy (allergy to pollens, etc) she may get hay-fever like symptoms, such as:

  • Inflammation
  • Itchiness
  • Redness
  • Lots of face rubbing
  • Scratching in some cases

The white of the eye and the conjunctiva can become red, swollen and irritated. Conjunctiva is all the tissues in and around the eye – the inside of the eyelids, the third eyelid, etc. Dogs with severe inhalation allergies can lose all the hair around their eyes.

Treating allergies is difficult … so find a holistic vet to help you out if your dog has this problem. 

RELATED: Read about some DIY allergy remedies … 


Conjunctivitis is a common condition in dogs caused by an infection. It can be bacterial or viral. If your dog has serious conjunctivitis, it’s painful. So you may see her squinting, even without a corneal ulcer. The signs of conjunctivitis include:

  • Mild reddening with no swelling to …
  • A tomato red eye with a lot of swelling of the conjunctiva
  • You’ll nearly always see a mucky eye discharge. The discharge can be mild … or thick and profuse in severe cases.

Mild cases of bacterial conjunctivitis may respond to washing the eyes every couple of hours with salt water or herbal tea.

To make your own salt water solution, place 1 tsp salt in a cup of boiling water. Allow it to cool. Use a glass dropper or a cotton ball to dribble the salt water into your dog’s eyes.

Chamomile, Calendula or herbal Euphrasia are great choices for a herbal tea rinse. Let the tea steep and cool, then use some cotton balls or pads to gently dribble the tea into your dog’s eyes. Wipe away any discharge. If the problem doesn’t improve or is getting worse, go see your vet.

Euphrasia in homeopathic form can also help with many eye issues. Using a 30C potency, give 3 oral doses a day for a day or two, then once a day until the problem resolves. 

Uveitis And Eye Infections In Dogs

Uveitis is inflammation of the whole eye. It’s not very common. It’s usually caused by a systemic infection or disease. This is a painful condition, and your dog may avoid bright light.

Infectious causes include:

  • Viral diseases (rabies, distemper)
  • Parasitic diseases (toxoplasmosis, ehrlichiosis)
  • Bacterial diseases (Lyme disease, leptospirosis)
  • (In rare cases) Fungal diseases (blastomycosis, histoplasmosis, cryptococcosis, coccidioidomycosis)
  • Metabolic disease (like diabetes) or high blood pressure

So you’ll likely need your vet’s help in figuring out the root of the problem. Once you know the cause, your vet can help you with a treatment plan.

If it’s a bacterial infection, the treatment will be intense but it gets better in a few days. There are more serious problems if it’s a viral disease like distemper. For a fungal infection, the red eye will get better after the whole dog is treated.

Poor Conformation

Breeds of dogs selected for a lot of folds and loose skin … (think Shar Pei, Bloodhound, Mastiff) … may have eyelid problems that can cause red eyes. 

The eyelid can fold out so that the eye is left without protection (ectropion).

Or it can fold in so that the eyelashes rub on the surface of the eye itself (entropion). These problems are severe. They nearly always require surgical correction to prevent severe damage to the eye over time.

Sometimes there will be a hair growing on the inside of the eyelid … even in dogs with good conformation. This is an ectopic cilia, which can cause corneal ulceration. It’s a rare problem, but if it happens, your dog will be squinting or holding her eye shut.


Glaucoma is a serious eye condition is caused by an increase in pressure in the eyeball. It happens when the normal healthy drainage of fluid from the eye is damaged. Primary glaucoma happens in several breeds, due to inherited anatomical abnormalities. Many popular breeds are prone to glaucoma 

Secondary glaucoma may be due to uveitis, intra-ocular bleeding, lens dislocation, tumors or damage to the lens.

Symptoms of Glaucoma in Dogs

Glaucoma can occur in one or both eyes. Often the blood vessels on the white of the eye become very obvious and swollen, and the affected eyeball may be visibly larger. It’s often very painful.

You may see tearing, squinting, redness, different-sized pupils, and even vision loss. 

Glaucoma is a serious problem, and in acute cases can cause blindness quite quickly. You’ll need help from a vet for this one. Homeopathic treatment can help with glaucoma so consider consulting a good homeopathic vet for a gentle, non-invasive way to treat this condition. 

Dry Eye Syndrome

Dry eye, or karatoconjunctivitis sicca, is usually an autoimmune disease, meaning your dog’s immune system attacks the eyes. It causes the tear glands to dry up. Rarer causes are damage to the nerves, drug side effects or some hormonal diseases.

Some breeds are more prone to dry eye … 

  • Cavalier King Charles Spaniel
  • Pug
  • West Highland White Terrier
  • American Cocker Spaniel
  • Shih Tzu

You’ll see a red, dry eye, often with a very tacky or sticky discharge. Again, this is a problem you’ll need to take to your vet. It’ll need lifelong treatment. However, I do recommend you consult a homeopathic vet to treat your dog’s dry eye. Homeopathy can be highly effective in treating dry eye … but don’t try to use it on your own. You’ll need a professional homeopath to prescribe a remedy that fits your dog’s overall symptoms.

Homeopathic Euphrasia, or these homeopathic eye drops may also relieve your dog’s dry eye as a safer alternative to antibiotic eye drops. But I recommend you only use them as part of a holistic treatment plan with your vet’s guidance.

Skin Diseases

Skin problems like mange, pyoderma, allergies … and even in some cases serious systemic disease like cancer, can also cause reddening and inflamed skin in the eye and conjunctiva. You may need your vet’s help in figuring out the root of the redness.

So there you have it … a comprehensive list of reasons why your dog’s eye(s) may be red.

Eyes are delicate organs … so I encourage you to seek proper treatment sooner rather than later if your dog’s eye issue doesn’t improve … and especially if things are getting worse. Any time you see squinting, take your dog to the vet, because squinting can often mean a corneal ulcer.. If you can, see a veterinary ophthalmologist instead of your regular vet. They’ll have more experience with eye issues. 


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