Conjunctivitis (Pink Eye) in Dogs: Causes, Treatment and Is It Contagious?

Signs of Conjunctivitis in Dogs

• Red eyes and red, swollen tissue around the eye^1,2
• Discharge that is watery, cloudy, yellow or green¹
• Squinting or blinking a lot¹
• Rubbing or pawing at the eyes⁵
• Sometimes sneezing, nasal discharge or coughing, which can point to a viral infection¹

Go to a vet the same day if your dog is in obvious pain, the eye looks cloudy, or your dog seems to have trouble seeing. These can mean an ulcer or glaucoma rather than simple conjunctivitis.^6,7

What Causes Pink Eye in Dogs?

• Allergies to pollen, dust mites and other things in the environment, often with itchy skin^1,3
• Dry eye (keratoconjunctivitis sicca, or KCS), one of the most common causes. Breeds at higher risk include Cavalier King Charles Spaniels, English Bulldogs, Lhasa Apsos, Pugs, Shih Tzus and West Highland White Terriers.^3,8
• Irritants and foreign bodies such as smoke, dust, shampoo or grass seeds^1,5
• Eyelid and eyelash problems, including inward- or outward-rolling eyelids and extra lashes¹
• Bacterial infection, usually secondary to another problem^1,3
• Viral infections such as canine distemper, canine herpesvirus and canine adenovirus^1,9,10
• Immune-related conditions, such as plasma cell conjunctivitis in German Shepherds¹
• Other eye diseases that cause red eyes, including corneal ulcers, glaucoma and uveitis¹

Whether one or both eyes are affected can give a clue. Trouble in one eye often points to something local, such as a foreign body, an ulcer, a tear-duct problem or an infection in that eye. Allergies and dry eye more often affect both eyes. It's only a clue, not a diagnosis.^2,5,8

Is Pink Eye in Dogs Contagious?

To people: it's possible but rare. Most causes of conjunctivitis in dogs, such as allergies and dry eye, aren't contagious at all, and most viruses that cause it infect only one species.^11,12,13 Wash your hands after cleaning your dog's eyes or giving eye medicine, and before touching your own face.^11,13

To other dogs: pink eye caused by contagious viruses can spread between dogs. Canine herpesvirus has caused outbreaks in groups of dogs, and distemper and adenovirus are contagious illnesses that also affect the eyes.^10,9,1 Bacterial pink eye is usually secondary to another problem.³ As a precaution, keep your dog away from other dogs' faces until your vet knows the cause, and keep your dog's vaccinations up to date.^4,9

Diagnosis

Because so many problems cause red eyes, appearance alone usually isn't enough.² Your vet will examine the eyes and may do a fluorescein stain to look for ulcers, a Schirmer tear test to measure tears, an eye pressure check, and sometimes a culture, cell sample or allergy testing.^1,4

Treatment

• Antibiotic drops or ointment for bacterial infection^1,2
• Anti-inflammatory drops, including steroids, for allergic and other inflammation, used only after an ulcer has been ruled out^1,14
• Tear-stimulating drops (cyclosporine or tacrolimus) for dry eye, usually for life^1,8
• Allergy treatment, which may include antihistamines your vet recommends¹⁵
• Surgery for eyelid or lash problems¹
• A cone if your dog is rubbing the eyes^15,5

With veterinary treatment, most uncomplicated cases clear up within about 7 to 10 days. Dry eye and immune-related conjunctivitis may need lifelong treatment.^15,1 Don't use medicine from a previous episode; it may not suit the current problem and could make it worse.^1,13

Home Care

• Gently clean away discharge with a cotton ball soaked in lukewarm water, or rinse with plain sterile saline eye wash.^5,16
• If your vet has prescribed drops, rinse the eye 10 to 15 minutes beforehand, not right before, so you don't wash the medicine away.¹⁶
• Keep your dog away from smoke, dust and other irritants.¹
• Don't use human eye drops, especially redness-relief drops such as Visine, which can be toxic to dogs, particularly if swallowed.^17,13

See dog eye infections for more on what else a red eye could be, and dog eye wash for how to clean your dog's eyes.

Frequently Asked Questions

Can you get pink eye from a dog?

It's possible but rare. Most causes of pink eye in dogs aren't contagious to people. Wash your hands after touching your dog's eyes.

Will conjunctivitis in dogs go away on its own?

Mild irritation from dust or smoke may settle, but most cases need a vet to find the cause. Untreated dry eye, ulcers and eyelid problems can damage the eye.

How long does pink eye last in dogs?

Most cases clear up within about 7 to 10 days of treatment. Dry eye and immune-related conjunctivitis may need lifelong care.

Can I use human eye drops for my dog's conjunctivitis?

No. Human drops, especially redness-relief drops, can be harmful. Use only what your vet prescribes; plain sterile saline is fine for rinsing.

Will Benadryl help my dog's pink eye?

It may help if allergies are the cause, but it won't treat infection, dry eye or other causes. Ask your vet before giving it.

Should I wipe my dog's eye discharge?

Yes. Gently wipe it away with a clean cotton ball soaked in lukewarm water, using a fresh one for each eye.

Is pink eye contagious to other dogs?

It can be when a contagious virus is the cause. Keep your dog away from other dogs until your vet knows what's causing it.