Conjunctivitis or Pink Eye In Dogs
Mon, October 25, 2021

Conjunctivitis or Pink Eye In Dogs


Conjunctivitis (pink eye) is the inflammation of the conjunctiva tissue, a mucous membrane that is akin to the lining of the mouth and nose, said Tammy Hunter, DVM, and Ernest Ward, DVM, or VCA Hospitals, an outlet of over 1,000 animal hospitals in the US and Canada.

The conjunctiva tissue covers your dog’s eyeball and lines the eyelids. They also have a third eyelid called the nictitating membrane located in the inner corner of the eye. When your dog is healthy, the conjunctiva of the eyelids is not that visible and has a pale, pink color. But when your pet has conjunctivitis, the said membranes become red and swollen.



Research On Ophthalmic Affections

Tamilmahan P. and colleagues of Veterinary World, a peer-reviewed journal outlet, conducted a retrospective study of ocular affections in domestic animals from January 2002 to December 2011. Corneal opacity was high in Caprine (38.88%), followed by Buffaloes (37.14%), Canines (29.41%), Cattle (28.57%), Equines (28.09%), Avian (25%), and Felines (25%).  Among dogs, Spitz had the highest incidences of cataract (60%) while Neopolitan Mastiff showed a high occurrence of cherry eye (62.8%).

Among eye disease conditions, corneal opacity was more prevalent (28%) compared to trauma (16.14%), miscellaneous (12.14%), conjunctivitis (7.13%), tumor/dermoids (4.75%), and amaurosis (4.50%). The researchers concluded that eye disorders are problematic among canines and equines. With regard to the sex of the animals, males were more affected (60.32%) than females (39.29%).

This supported a similar occurrence among male canines (61.17%) and male equines (71.90%) compared to female canines (38.82%) and equines (28.09%). It is recommended for health care to perform regular ophthalmic examination and screening as part of healthcare in domestic and pet animals.

Tarun Kumar and colleagues of journal portal Research Gate conducted a study to find out the occurrence of ocular affections with respect to the dogs’ breed, age, sex, and type of affections from July 2017 to June 2018. Most ophthalmic affections were recorded among dogs aged 0-3 years (51.7%), followed by 3-6 years (36.7%), and 6-9 years (11.6%). This can be attributed to the playful nature of younger dogs, making them more susceptible to traumatic injuries. Sex wise, ocular affections were more prevalent in male dogs (65%) than females (35%).

The occurrence of ophthalmic affections among breeds was highest in Pugs (28.3%), followed by non-descript (21.7%), and Labrador (20%). The breeds with the least occurrence were Spitz (15%), German Shepherd (11.7%), and Bully breed (3.3%). As for the type of lesions, keratitis (21.7%) and corneal ulcer/injury (21.7%) had the highest occurrence, followed by corneal opacity (18.3%), epiphora (11.6%), cloudy eye (8.3%), cataract and blepharitis (6.7%), and dry eye (5%).



What Are the Causes and Signs of Conjunctivitis?

It is caused by viral infections like canine distemper virus or immune-mediated disorders such as allergic conjunctivitis, plasma cell conjunctivitis, and pemphigus. Tumors of the eyelids and conjunctiva can also cause conjunctivitis. Eyelid abnormalities like entropion or ectropion and eyelash disorders such as distichiasis and ectopic cilia usually cause secondary conjunctivitis.

Inflammatory conjunctivitis is caused by trauma to the eye or irritation from foreign bodies, smoke, or environmental pollutants. Ulcerative keratitis, anterior uveitis, and glaucoma can also be contributing factors to conjunctivitis.  

One of the common symptoms of conjunctivitis is discharge from the eyes. The discharge can be cloudy, yellow, or greenish. Other signs you need to watch out for are squinting or excessive blinking, as well as redness or swelling around your dog’s eyes. Conjunctivitis usually involves both eyes, but one eye may be affected in certain conditions. It may occur with other symptoms such as sneezing, coughing, or nasal discharge.



How Is Conjunctivitis Diagnosed?

The main objective of the diagnosis is to identify whether the conjunctivitis is a primary or secondary problem, if there is an additional disease or damage to the eye, if the condition is allergic, or if it involves the sclera itself. Your pet dog may exhibit one or all of the symptoms of conjunctivitis, but that is not enough to provide an accurate diagnosis, noted Kristina Lotz of the American Kennel Club (AKC), a website dedicated to publishing canine-related content.

Hence, your vet will perform a complete and detail ophthalmic examination to differentiate these conditions. The procedure will include a detailed examination of the surrounding eye structures, namely the eyelids, eyelashes, tear ducts, third eyelid, etc.

Your vet will also do tear production tests and corneal stain tests to find out if the cornea is damaged or not. Additionally, intraocular pressure will be measured to determine any signs of glaucoma or uveitis. However, your vet may also perform additional tests and procedures such as nasolacrimal duct flushing, bacterial culture and sensitivity tests, conjunctival cytology or biopsy, and allergy testing.

How Is Pink Eye Treated?

Treatment plans are geared to address the specific cause of conjunctivitis, which may include both oral and topical medications. Topical gentamicin, tobramycin, chloramphenicol, oxytetracycline, ciprofloxacin or triple-antibiotic ophthalmic ointments and solutions are commonly administered to combat pink eye.

It is possible for some dogs to receive medications infused with anti-inflammatory agents such as ophthalmic prednisolone or dexamethasone. If your dog has secondary conjunctivitis, oral antibiotics or anti-inflammatory medications may be prescribed.

If it is diagnosed with dry eye, your dog will need to be administered with cyclosporine or tacrolimus to help produce tears. Canines with eyelid or eyelash abnormalities will need to undergo surgery. Don’t worry, your vet will teach you how to safely administer the eye drops to your dog.

Is It Possible to Prevent Pink Eye?

Be sure to keep your dog’s vaccines like distemper up to date to prevent some of the viral causes of pink eye. It is recommended to supervise your dogs during playtime to prevent trauma.

If you own a brachycephalic dog, discourage it from engaging in behaviors that may cause eye damage. These behaviors include provoking cats or sniffing around thorn bushes. When you’re traveling with your dog, it should be safely secured in a pet travel crate or car seat. Don’t let it stick its head out of the window when you are driving as flying dirt and debris could enter its eyes.

Exercise caution when letting your dog play or explore its surroundings to prevent eye damage. Ensure that your dog’s vaccines are updated to curb the viral causes of pink eye. If you notice any signs of conjunctivitis, consult your vet for early intervention and treatment.