Pink eye in dogs is quite common. Things like allergies, injury, eye irritants and infections can all cause dog pink eye, and just like in humans, it can be contagious. It has also been found that lyme disease can cause pink eye symptoms. Typically if only one eye is affected, it's likely a foreign object, while pink eye generally affects both eyes. Sometimes antibiotic ointment applied to the eye is necessary or possible even a flushing of the eye to remove any foreign object. Signs your dog might have pink eye would be an increased discharge from the eye(s) (possibly yellow or greenish in color), redness and swelling making it sometimes difficult to open the eyes, possible sensitivity to light and possibly even a slight change in your dog's behavior such as sleeping in a darkened room more often. Unlike in humans, your dog's eyes may or may not be itchy. Certainly if they are itchy, you will notice your dog attempting to rub his eyes on furniture, carpet etc. Most pink eye in dogs should clear up with home treatment in a week or two. If you're sure there is no foreign object in the eye which would require a veterniarin, home treatment would include gently wiping the eye area with a warm washcloth to clear away itchy discharge a few times a day (using a seperate cloth for each eye as not to spread infection) and instilling artificial tear drops. If your vet feels it's a more significant infection, antiobiotic drops or ointment might be prescribed. Serious infections left untreated can lead to loss of vision.