Causes of Excessive Tear Production in Dogs
Excessive tearing in dogs is commonly caused by: - Blocked tear ducts (nasolacrimal occlusion), especially in breeds like Cocker Spaniels. - Cherry eye, where the tear gland of the third eyelid prolapses. - Eye irritation from foreign bodies, extra eyelashes, or facial hairs. - Inflammation from conjunctivitis, corneal ulcers, or allergies. - Congenital defects such as imperforate inferior punctum.
Blocked Tear Drainage System
A major cause of excessive tearing is a blockage in the nasolacrimal duct, the system that drains tears from the eye into the nose. This condition, known as nasolacrimal occlusion, can be present at birth—such as in imperforate inferior punctum, where a membrane blocks the lower eyelid’s tear duct opening. It can also result from entropion (inward rolling of the eyelid), scarring after infection, or duct infections. When tears can’t drain properly, they overflow, causing a watery eye and potential skin irritation.
Cherry Eye and Tear Gland Issues
Cherry eye occurs when the tear gland attached to the third eyelid prolapses, exposing a red, swollen mass. This gland is a major source of tears, and its displacement can lead to chronic irritation and excessive tearing. Removing the gland risks causing dry eye, so surgery to reposition it is preferred. Breeds like Cocker Spaniels, Beagles, and Bulldogs are especially prone.
Eye Irritation and Foreign Bodies
Foreign objects like grass seeds, dirt, or splinters can get trapped in the eye or behind the eyelids, causing pain, squinting, and excessive tearing. Dogs running through tall grass or riding with their head out of car windows are at higher risk. Irritation from extra eyelashes or facial hairs rubbing on the eye surface can also trigger watery discharge. Prompt removal of foreign material is essential to prevent corneal damage.
Inflammation and Infection
Conjunctivitis, or inflammation of the eye’s lining, often causes redness and discharge. While not always painful, it can lead to excessive tearing, especially if one eye is affected. Corneal ulcers, anterior uveitis, and acute glaucoma are painful conditions that also result in watery eyes. Neonatal conjunctivitis in puppies can cause pus buildup and eyelid fusion, requiring immediate treatment to prevent blindness.
Allergies and Other Causes
Allergic reactions can cause eye irritation, leading to tearing and itching. These reactions are usually temporary and improve when the allergen is removed. Corticosteroid eye drops or oral antihistamines may be prescribed. In rare cases, nerve injury from middle ear infections or systemic diseases like canine distemper can impair tear production, but this leads to dry eye, not excessive tearing.
Frequently asked questions
Can excessive tearing cause skin problems?
Yes, constant wetness from epiphora can inflame and infect the skin around the eyes, worsening discomfort and appearance.
Is cherry eye treatable without surgery?
No—surgical repositioning is recommended to preserve tear production and prevent chronic irritation.
Sources
- Dog Owners Home Veterinary Handbook · Debra M. Eldredge · Chapter on Epiphora and Tear Mechanism
- Dog Owners Home Veterinary Handbook · Debra M. Eldredge · Chapter on Conjunctivitis and Foreign Bodies
- Dog Owners Home Veterinary Handbook · Debra M. Eldredge · Chapter on Dry Eye (Keratoconjunctivitis Sicca)
⚠️ Important: this article is a literature summary, not a case diagnosis. Every dog is different — breed, age, and history all affect the plan. For severe anxiety or aggressive barking, contact a certified behavior trainer or veterinary behaviorist.