In dogs, eye infections can cause red, irritated eyes and various types of eye discharge. To help dog parents recognize when their dog might have an eye infection and know what to do, integrative veterinarian Dr. Julie Buzby discusses the causes, symptoms, diagnosis, treatment, and prognosis for eye infections in dogs.
You’ve probably heard of pinkeye and maybe experienced it, too. Either way, if your dog suddenly has a red, goopy, irritated eye, it would be natural to wonder if he or she had an eye infection like pinkeye.
As it turns out, dogs do get eye infections. But for them, eye infections often occur secondary to some other eye problem. Let’s take a closer look.
What is a dog eye infection?
A dog eye infection is a condition where bacteria, viruses, fungi, or parasites invade the eye, multiply, and cause inflammation. The location of the infection can be the:
- Cornea (clear “windshield” in the front of the eye)
- Conjunctiva (clear to light pink tissue lining the eyelids and reflecting onto the surface of the eye)
- Uvea (iris, ciliary body, and choroid within the eye)
- Eyelids
Eye infections involving the conjunctiva are the most similar to pinkeye in humans because they cause conjunctivitis—inflammation of the conjunctiva. However, there are also many non-infectious reasons for conjunctivitis, such as allergies or foreign material (more on this soon).
Infectious conjunctivitis plus corneal infections will be the main types of eye infections discussed here, as they are what dog parents would most commonly associate with the word “eye infection.” If you are looking for information about infections involving the uvea, check out this article on uveitis in dogs.
Many eye conditions have similar signs, but the outlook can vary. If your dog’s eye is swollen, red, or painful, he or she is holding it closed, or you have any concerns, please stop reading this article and call your vet. Eyes can go bad quickly. In some situations, deciding to go to the vet sooner rather than later can save your dog’s sight or eye, especially if your dog has something more serious going on than an eye infection.
What causes eye infections in dogs?
The infectious agents that cause eye infections in dogs include:
- Bacteria: Some of the most common include Staphylococcus and Streptococcus species, Bordetella (the bacterium associated with kennel cough), and the bacteria responsible for tick-borne disease in dogs, such as Ehrlichia and Borrelia burgdorferi (causative agent of Lyme disease).
- Viruses: Canine distemper virus and canine herpesvirus are more frequent causes of eye infections, and both can affect the respiratory tract as well. Herpesvirus can also cause chronic relapsing infections.
- Fungal: Some fungal species, like Aspergillus and Candida, can be present in mild infections, but more serious infections, such as Blastomyces and Cryptococcus, are also possible.
- Parasites: Potential parasites that could infect the eye include Leishmania, Onchocerca, and bot fly larva (Cuterebra species).
Are dog eye infections contagious?
Some bacterial or viral infections of the eyes, such as those caused by Bordetella, canine distemper virus, and canine herpesvirus, are directly contagious from dog to dog. Others are not contagious. It just depends on the organism causing the eye infection.
What other conditions increase the chances of a bacterial eye infection in dogs?
Interestingly, primary bacterial conjunctivitis is uncommon in dogs. In other words, dogs are unlikely to have a bacterial infection involving the conjunctiva that occurs without some sort of inciting cause. They usually don’t just happen out of the blue.
Instead, if a dog has bacterial conjunctivitis, it is usually secondary. This means that some other eye condition or injury sets the stage for bacteria to invade and cause an infection. Some of the more common conditions include:
Allergies
Itching and skin inflammation are the most common manifestations of seasonal allergies in dogs. But some dogs will also have allergic conjunctivitis. Signs occur after exposure to allergens like pollen, molds, and dust mites. Plus, irritants such as smoke and dust can result in redness and inflammation of the eyes.
Allergic conjunctivitis in dogs tends to cause symptoms that look a bit like an infection. Plus, because of the inflammation and the fact that they may rub at their itchy eyes, dogs with allergies can also develop secondary eye infections.
Your vet will help determine if your dog has an eye infection, allergies, or both. But generally speaking, allergic conjunctivitis causes both eyes to be itchy with watery discharge. An eye infection tends to just happen in one eye and is usually accompanied by greenish or yellowish discharge.
Irritation or trauma to the eye
Trauma to the eye and surrounding tissues can lead to conjunctivitis or a corneal ulcer in dogs. As a result, the dog may develop a secondary eye infection. Sometimes the injury to the eye is a result of foreign bodies such as hair, dirt, sticks, mulch, grass clippings, a foxtail in dogs, etc., getting into the eye. Other times, it might be a chemical irritant, such as shampoo or a cleaning product.
Whatever the cause, tissue irritation and/or a break in the surface of the cornea allows bacteria to invade and cause an infection. This, in turn, can worsen the ulcer or conjunctivitis.
Dry eye
In keratoconjunctivitis sicca (KCS), commonly called dry eye in dogs, the dog isn’t producing enough tears. Since tears help protect and cleanse the eye, dogs with untreated KCS can develop corneal ulcers and/or eye infections.
KCS can impact one or both eyes at the same time. And it usually causes a thick, green, mucoid discharge to form over a dog’s eye(s). This can make it look like an eye infection, but the dog can also have both an infection and KCS.
Eyelid or eyelash abnormalities
If the dog’s eyelids or eyelashes are abnormal, this can lead to irritation of the cornea and conjunctiva and set the stage for an eye infection. Some of the more common culprits include:
- Entropion: Eyelids that roll inward so that the eyelashes rub the sensitive cornea
- Ectropion: Eyelids that roll out, exposing the conjunctiva and making it prone to drying and irritation
- Distichiasis in dogs: Eyelashes that grow in an abnormal location and rub on the cornea
- Trichiasis: The fur on the dog’s face grows toward the eye and irritates it
- Cherry eye in dogs: The tear gland that is normally tucked under the third eyelid pops out of position
Tumors of the eye
Some tumors (cancerous or noncancerous) can cause local inflammation and damage to the eye and its surrounding structures. This can make it easier for dogs to develop eye infections because the eye’s defenses are impaired.
What are the symptoms of a dog eye infection?
It can be difficult to distinguish the clinical signs of a dog eye infection from the appearance of other eye conditions. Dogs with problems like allergies, ulcers, glaucoma in dogs, foreign objects in the eye, and dry eye can have symptoms that resemble those of an infection (and some might have one of those problems plus an infection).
Potential symptoms of an eye infection include:
Discharge from the eye
A goopy eye in dogs can be a sign of many common types of eye problems. However, with an eye infection, the dog may have:
- Clear or serious discharge: This is usually a watery, see-through fluid that may run down the side of the face.
- Green or yellow discharge: You might notice discharge ranging in color from grey to yellow or greenish. The material may be thin or thick.
Redness of the conjunctiva
Inflammation leads to increased blood flow (hyperemia) in the conjunctiva, which makes the tissue look redder than normal. Aside from allergies and bacterial infections, internal eye conditions such as uveitis and glaucoma can also cause a red eye.
Swelling of the conjunctiva (chemosis)
You might notice a swollen eye in dogs, specifically swelling or puffiness of the conjunctiva. Any eye condition resulting in infection or inflammation can cause chemosis, as can trauma and foreign bodies.
Squinting, blinking, or holding the eye closed
A dog with a painful, irritated, or itchy eye may squint or blink frequently. With more severe pain or irritation, he or she may even hold the eye closed.
Light sensitivity (photophobia)
When exposed to bright lights or sunlight, dogs with conjunctivitis and other eye problems may squint, shy away, or try to hide.
Pawing or rubbing at the eye
Pawing or rubbing at the eye is another sign of ocular pain, discomfort, or itchiness. Unfortunately, dogs can cause even more damage to the eye when they rub at it.
Cloudy eye
With uveitis or infections that are secondary to a corneal ulcer, you might notice a cloudy eye in dogs. This could be the surface of the eye or the inside of the eyeball itself.
Head to the vet
If you are seeing some of these symptoms, promptly make an appointment with your vet. Eyes can go from bad to worse in a short period of time without veterinary attention. Thus, it is important you don’t delay in getting your dog the help he or she needs.
If your dog is holding the eye closed or squinting significantly, the eye and surrounding tissue are very red and inflamed, your dog seems painful, or the eye has suddenly turned cloudy or deflated, your vet may advise you to make an emergency vet visit.
How will the vet diagnose an eye infection?
During the appointment, your vet will examine your dog as a whole. Plus, he or she will perform some specific tests on your dog’s eyes. Since there is a lot of overlap in symptoms for the various eye conditions, the eye-specific tests can help distinguish between them. Some of these tests and examinations include:
- Visual exam: Careful observation of the eyelids, eyelashes, third eyelid, conjunctiva, and surface of the eye for abnormalities
- Schirmer tear test (STT): Using a thin paper to measure tear production in both eyes. STT is the main diagnostic for confirming or ruling out dry eye.
- Fluorescein eye stain: Applying a special stain that sticks to defects in the cornea and fluoresces (glows) under blacklight. It is helpful for highlighting ulcers or scratches on the cornea.
- Tonometry: Evaluating the intraocular pressure (pressure within the eye) using a specialized, battery-operated tool. A low pressure finding points to uveitis, and a high pressure finding points to glaucoma.
If your dog is having symptoms that affect other parts of the body, your veterinarian may recommend a combination of blood tests for dogs, urine tests, skin tests, etc. Imaging, such as X-rays or ultrasound, is also possible.
After collecting the diagnostic information, the vet will let you know which condition (or conditions) are most likely to be responsible for your dog’s symptoms. Then he or she will work with you to develop a treatment plan.
What is the treatment for dog eye infections?
Treatment for dog eye infections involves addressing the infection itself as well as the underlying cause of the infection.
Antibiotic and anti-inflammatory eye medication
If the vet suspects a bacterial eye infection (bacterial conjunctivitis), he or she will typically prescribe a topical eye drop or ointment that combines antibiotics with an anti-inflammatory, which is usually some type of steroid. This treats the eye infection while also minimizing inflammation to provide relief to your pup. (If the dog has a corneal ulcer, the vet will skip the topical steroid component as steroids can slow ulcer healing.)
Most of the time, you will need to apply the eye medications two to three times a day. If your dog needs more than one eye medication, your vet will instruct you on how to space them out and which to do first. Learning how to give a dog eye drops or eye ointment can feel challenging at first, but with patience and practice, you will get it down.
Pain medications and E-collar if needed
For particularly painful eyes, the vet may also prescribe an oral medication to relieve pain. And if the dog is rubbing or pawing at the eye, sometimes an E-collar is necessary. No one likes to have their dog end up in the “cone of shame,” but it is worth it if it keeps your dog’s eye safe.
Managing the underlying problem
Additionally, the vet will take steps to manage any underlying conditions. Depending on the type of problem, this might involve a medication like cyclosporine to help stimulate tear production in dogs with KCS. Or dogs with allergic conjunctivitis might need allergy medicine for dogs or steroid eye drops. Alternatively, sometimes the vet will need to remove a foreign object from the eye or perform eyelid or cherry eye surgery. Your vet will help you understand what is best for your dog’s particular situation.
Are there home remedies for dog eye infections?
There are not any effective home remedies for dog eye infections, and trying to treat your dog at home can have disastrous consequences.
The symptoms of an eye infection can be very similar to other, more concerning problems like corneal ulcers or glaucoma. Thus, it could be dangerous to assume that all your dog has is an eye infection. Left untreated, acute glaucoma can lead to blindness, and a deep corneal ulcer can cause the eye to rupture. Plus, even if it isn’t glaucoma or an ulcer, eye conditions in general have the potential to worsen quickly.
For all these reasons, you need to get your dog to the vet to get an accurate diagnosis and the appropriate treatment, not reach for home remedies. For your dog’s sake, please resist the temptation to try colloidal silver, black tea, aloe vera, apple cider vinegar, coconut or castor oil, chamomile, or any of the other natural remedies you may find on the internet.
What about rinsing my dog’s eye out with a saline solution?
With your vet’s permission, there are some situations where saline eye wash may be helpful. (The key here is “with your vet’s permission” as saline solution isn’t right for everything.)
Saline for flushing out the eye
If you think your dog may have foreign material or an irritating substance in the eye, your vet may have you try gently rinsing out the eye with plain saline eye solution. But if your dog seems uncomfortable or painful, it’s best to stop and wait for your appointment.
Additionally, there might be a few conditions, such as allergic conjunctivitis, where the vet suggests using a saline solution to flush allergens or irritants out of the eye. However, this is something you should do on the recommendation of your vet, not as a substitute for veterinary care.
Saline can clean infected eyes but not treat the infection
In the case of a suspected eye infection, rinsing the eye with saline solution isn’t going to treat the infection or the underlying cause of the infection. If your vet suggests it, you could use saline to loosen the eye debris and soothe the eye while waiting for your appointment. But you shouldn’t use it as a remedy for eye infections. Veterinary care is still the best solution for your dog’s eye infection.
Precautions for using saline
If your vet does recommend trying saline, ensure you don’t use any products with added ingredients. Plain saline eye wash is key. Also, be careful that you don’t put too much pressure on your dog’s eye when holding it open. Eyes can be fragile, especially if the dog has a corneal injury or ulcer.
How long do eye infections last in dogs?
When discussing the treatment plan, your vet will also give you an idea of how long it should take for your dog’s eye infection to improve. There isn’t one set timeframe since there are a variety of conditions that can lead to an eye infection, and some may be chronic or recurrent.
What you need to keep in mind is that if your dog’s eyes seem to be looking worse or getting more uncomfortable, or if they don’t seem to be improving as expected, it is important to contact your vet. That way, he or she can recheck the eye, run additional tests, and modify the treatment plan accordingly.
Is it possible to prevent dog eye infections?
It isn’t possible to prevent every eye infection in dogs. But the following tips can be helpful for decreasing the risk of one occurring.
- Ensure your dog is up to date on his or her vaccinations and receives the recommended parasite preventives.
- If your dog has long hair, keep the hair around the eyes trimmed and clean.
- Regularly inspect your dog’s eyes and eyelids for any issues and report them to your vet promptly.
- Follow your vet’s recommendations for managing underlying problems such as dry eye or allergies.
Work with your vet to manage your dog’s eye infection
If your dog has red, inflamed eyes, discharge from the eyes, or another eye problem, the best thing you can do is promptly contact your veterinarian. Please do not try any home remedies or take a “give it a few days and see what happens” approach.
The sooner you get your dog to the vet, the sooner you will know what is causing the eye issue—be it an eye infection or something else. With a diagnosis and appropriate treatment, hopefully your dog will be back to normal in no time.
Has your dog ever had an eye infection?
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