1. Eye Allergies (Very Common)

Just like humans, dogs can get eye redness from allergies.

Symptoms

• Red or bloodshot eyes

• Watery discharge

• Mild swelling

• Itching or rubbing

Common triggers

• Pollen

• Dust

• Mold

• Smoke

• Certain foods

Allergy-related redness often affects both eyes and improves when the trigger is removed.

2. Eye Infections (Bacterial or Viral)

Eye infections are a top reason for dog bloodshot eyes.

Symptoms

• Redness with thick discharge

• Yellow or green mucus

• Squinting

• Crusting around the eye

Infections usually don’t heal on their own and need vet-prescribed medication.

3. Injury or Foreign Object

If your dog was playing too hard, running through bushes, or digging in the dirt, they might have gotten a small scratch or something stuck in their skin.

Symptoms

• Redness in one eye only

• Sudden onset

• Pawing at the eye

• Squinting or blinking a lot

This is often why pet parents search:
“why is my dog’s eye red in one eye only?”

4. Dry Eye (Keratoconjunctivitis Sicca)

Dry eye happens when your dog doesn’t produce enough tears.

Symptoms

• Red, irritated eyes

• Thick discharge

• Dull or dry-looking eye surface

This condition requires long-term management with vet guidance.

5. Glaucoma (Emergency Condition)

Glaucoma is caused by increased pressure in the eye and can lead to blindness.

Symptoms

• Severe redness

• Bulging eye

• Cloudiness

• Pain

• Sudden vision loss

If you’re asking “is a red eye in dogs an emergency?”, glaucoma is a definite yes.

6. Uveitis (Internal Eye Inflammation)

Uveitis is inflammation inside the eye and can be linked to infections, immune issues, or trauma.

Symptoms

• Deep red eye

• Sensitivity to light

• Squinting

• Cloudy appearance

This always requires veterinary attention.