Conjunctivitis in Dogs: Complete Guide to Causes and Care

What is Conjunctivitis in Dogs?

Conjunctivitis, commonly known as pink eye, is inflammation of the conjunctiva—the thin, transparent membrane that covers the front surface of the eyeball (the sclera) and lines the inner surfaces of the eyelids. When the conjunctiva becomes inflamed, the blood vessels within it dilate and become more visible, giving the eye a red or pink appearance. This condition is one of the most common eye problems in dogs, affecting canines of all breeds and ages.

Conjunctivitis can affect one eye (unilateral) or both eyes (bilateral) and may be either a primary condition or secondary to another underlying problem. Understanding the different types of conjunctivitis, their causes, and appropriate treatments is essential for maintaining your dog’s eye health and overall wellbeing.

Types and Causes of Conjunctivitis in Dogs

Conjunctivitis in dogs can be categorized based on its underlying cause. Each type may present slightly different symptoms and requires specific treatment approaches:

Allergic Conjunctivitis

Allergic conjunctivitis occurs when a dog’s immune system reacts to environmental allergens. Common triggers include:

• Pollen from trees, grasses, and weeds
• Dust mites and household dust
• Mold spores
• Cigarette smoke
• Perfumes and air fresheners
• Certain cleaning products
• Specific fabrics or materials

Allergic conjunctivitis typically affects both eyes simultaneously and may be seasonal or year-round, depending on the allergen involved.

Infectious Conjunctivitis

Infectious conjunctivitis is caused by bacterial, viral, or fungal pathogens:

• Bacterial conjunctivitis is commonly caused by Staphylococcus, Streptococcus, or Pseudomonas species. It often produces a thick, purulent (pus-like) discharge.
• Viral conjunctivitis is less common in dogs than in humans and cats but can occur alongside respiratory infections. It typically causes a watery discharge.
• Fungal conjunctivitis is rare but can develop in dogs with compromised immune systems.

Irritant Conjunctivitis

This type of conjunctivitis occurs when physical or chemical irritants come into contact with the eye. Common irritants include:

• Foreign bodies (dirt, grass seeds, small particles)
• Smoke
• Shampoo or soap
• Wind or dust
• Chemicals

Secondary Conjunctivitis

Secondary conjunctivitis develops as a result of another primary eye condition. Common underlying causes include:

• Keratoconjunctivitis sicca (KCS) or dry eye, where insufficient tear production leads to inflammation
• Entropion or ectropion (abnormal positioning of the eyelids)
• Distichiasis (abnormal growth of eyelashes that irritate the eye)
• Corneal ulcers or other corneal injuries
• Glaucoma (increased pressure within the eye)
• Uveitis (inflammation of the middle layer of the eye)

Symptoms of Conjunctivitis in Dogs

Recognizing the signs of conjunctivitis early can lead to prompt treatment and prevent potential complications. Common symptoms include:

• Redness in the white part of the eye or inner eyelids
• Swelling around the eyes or eyelids
• Increased blinking or squinting
• Pawing at the eyes or rubbing face against furniture or carpeting
• Eye discharge (may be clear and watery, mucus-like, or thick and purulent)
• Crusting around the eyes, especially after sleep
• Visible third eyelid (nictitating membrane)
• Sensitivity to light (photophobia)
• Cloudy appearance to the eye

The specific symptoms and their severity often depend on the underlying cause of the conjunctivitis. For example, allergic conjunctivitis typically presents with itchiness and watery discharge, while bacterial infections often cause thicker, yellowish-green discharge.

Diagnosis of Conjunctivitis in Dogs

Proper diagnosis of conjunctivitis is essential for effective treatment. Your veterinarian will perform a thorough examination to determine whether your dog has primary conjunctivitis or if the inflammation is secondary to another condition.

Veterinary Examination

The diagnostic process typically involves:

• A detailed history of your dog’s symptoms and possible exposure to allergens or irritants
• A complete ophthalmic examination using an ophthalmoscope to examine the eye and surrounding structures
• Evaluation of the eyelids, eyelashes, tear ducts, third eyelid, and other related structures

Diagnostic Tests

Several specialized tests may be performed to pinpoint the cause:

• Schirmer tear test: Measures tear production to diagnose or rule out dry eye (KCS)
• Fluorescein staining: Identifies corneal ulcers or injuries that might be causing secondary conjunctivitis
• Intraocular pressure measurement: Rules out glaucoma or uveitis
• Bacterial culture and sensitivity testing: Identifies specific bacteria and appropriate antibiotics
• Conjunctival cytology or biopsy: Examines cells from the conjunctiva to identify inflammation patterns, infection types, or abnormal cells
• Nasolacrimal duct flushing: Checks for blockages in tear drainage
• Allergy testing: May be recommended in cases of suspected allergic conjunctivitis

These diagnostic procedures help your veterinarian differentiate between primary conjunctivitis and secondary inflammation caused by other eye disorders, ensuring that the appropriate treatment plan is implemented.

Treatment of Conjunctivitis in Dogs

The treatment for conjunctivitis varies depending on the underlying cause. Your veterinarian will prescribe a specific treatment plan tailored to your dog’s condition:

Allergic Conjunctivitis Treatment

• Topical eye drops or ointments containing steroids to reduce inflammation
• Oral antihistamines to control allergic reactions
• Oral steroids in more severe cases
• Identification and elimination of allergens when possible
• Environmental modifications to reduce exposure to triggers

Bacterial Conjunctivitis Treatment

• Topical antibiotic eye drops or ointments
• Oral antibiotics in severe cases
• Anti-inflammatory medications to reduce swelling and discomfort

Viral Conjunctivitis Treatment

• Supportive care and time (many cases resolve as the virus runs its course)
• Oral antioxidants to boost the immune system
• Topical or oral antiviral medications in specific cases
• Treatment of secondary bacterial infections if present

Treatment for Secondary Conjunctivitis

• For KCS (dry eye): Medications like cyclosporine or tacrolimus to stimulate tear production, along with lubricating eye drops
• For eyelid abnormalities: Surgical correction of entropion, ectropion, or distichiasis
• For foreign bodies: Removal of the object, often requiring sedation
• For blocked tear ducts: Surgical intervention to open the duct

Your veterinarian may also recommend the use of an Elizabethan collar (E-collar) to prevent your dog from scratching or rubbing their eyes, which could cause further damage or delay healing.

Home Care for Dogs with Conjunctivitis

While professional veterinary treatment is essential, there are several ways you can care for your dog at home during recovery:

Medication Administration

• Follow your veterinarian’s instructions carefully regarding medication dosage and frequency
• Learn proper techniques for applying eye drops or ointments
• Complete the full course of prescribed medications, even if symptoms improve

Eye Cleaning

• Gently clean away discharge using a clean, damp cloth or sterile eye wipes
• Wipe from the inner corner outward, using a fresh section of cloth for each eye
• Never use soap or other cleaning products unless specifically recommended by your veterinarian

Environmental Management

• Reduce exposure to potential irritants and allergens
• Keep your home clean and dust-free
• Use air purifiers if helpful
• Consider replacing air filters more frequently

Prevention of Conjunctivitis in Dogs

While not all cases of conjunctivitis can be prevented, several strategies can help reduce the risk:

• Regular eye examinations as part of routine veterinary check-ups
• Prompt attention to any eye abnormalities or changes
• Keeping your dog’s face clean, especially around the eyes
• Trimming hair around the eyes carefully to prevent irritation (for breeds with long facial hair)
• Avoiding exposing your dog to smoke, strong chemicals, or known allergens
• Using protective eyewear (doggy goggles) for dogs that ride with their heads out of car windows or participate in activities where eye injuries are possible
• Checking eyes regularly for signs of redness, discharge, or discomfort

In general, preventing further damage to the eye while treating the underlying issue is most important for healing. An Elizabethan collar or pet cone is helpful to avoid your dog rubbing their face or scratching their eyes, which can cause abrasions (scrapes) or even perforations (holes) in the cornea.

When to Seek Veterinary Care

Eye problems can quickly become serious, so it’s important to seek veterinary attention promptly if you notice any of these signs:

• Eye redness that doesn’t resolve within 24 hours
• Discharge from the eye (especially if thick or colored)
• Squinting or excessive blinking
• Pawing at the eye or rubbing the face
• Visible swelling around the eye
• Cloudiness in the eye
• Any change in the appearance of the eye
• Signs of pain or discomfort

Never attempt to treat eye problems at home without veterinary guidance, as improper treatment can lead to worsened conditions or even permanent damage to your dog’s vision.

Frequently Asked Questions (FAQs) About Canine Conjunctivitis

Q: Is conjunctivitis contagious between dogs?

A: Some forms of infectious conjunctivitis can be contagious between dogs. If your dog has been diagnosed with conjunctivitis, it’s best to keep them separated from other pets until your veterinarian confirms it’s non-contagious or the infectious period has passed.

Q: Can humans catch conjunctivitis from dogs?

A: Most cases of canine conjunctivitis are not transmissible to humans. However, in rare cases involving certain bacteria, there might be a risk. Always practice good hygiene when handling a dog with eye infections, washing your hands thoroughly afterward.

Q: How long does it take for conjunctivitis to clear up in dogs?

A: Recovery time varies depending on the cause. Simple cases might improve within a few days of starting treatment, while more complex cases could take weeks. Complete resolution of symptoms is essential, and you should continue treatment for the full course prescribed by your veterinarian.

Q: Are certain dog breeds more prone to conjunctivitis?

A: Yes, breeds with prominent eyes (brachycephalic breeds like Bulldogs, Pugs, and Boston Terriers), those with excessive facial folds, or breeds prone to certain eye conditions (like Cocker Spaniels and their vulnerability to dry eye) may be more susceptible to conjunctivitis.

Q: Will conjunctivitis affect my dog’s vision?

A: When promptly and properly treated, most cases of conjunctivitis do not cause permanent vision damage. However, if left untreated or if associated with more serious conditions like corneal ulcers or glaucoma, vision impairment can occur.

Q: Can I use human eye drops for my dog’s conjunctivitis?

A: No. Never use human medications for your dog without veterinary approval. Many human eye products contain ingredients that could be harmful to dogs or inappropriate for their specific condition.

Q: How can I tell if my dog’s eye redness is conjunctivitis or something more serious?

A: Only a veterinarian can accurately diagnose the cause of eye redness. Other serious conditions like glaucoma, corneal ulcers, or uveitis can sometimes be mistaken for simple conjunctivitis but require very different treatments. When in doubt, always consult your veterinarian.

Remember that eye problems should always be taken seriously. Prompt veterinary attention for any eye abnormalities can help prevent complications and ensure your dog maintains healthy vision throughout their life.

Author

Shinta

 

Shinta is a biotechnologist turned writer. She holds a master's degree in Biotechnology from Karunya Institute of Technology and Sciences and a PG Diploma in cellular and molecular diagnostics from Manipal University. Shinta realised her love for content while working as an editor for a scientific journal.

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