The normal tear film is produced continuously by the lacrimal gland (aqueous component) and meibomian glands (lipid component) and drains via the nasolacrimal system: tears flow across the ocular surface, collect at the medial canthus (inner corner of the eye), enter the superior and inferior puncta (small openings at the medial eyelid margins), pass through the canaliculi into the lacrimal sac, and drain into the nasal passage. This drainage is normally sufficient to handle baseline tear production, and tears do not overflow onto the face. Overflow tearing (epiphora) occurs when this system is disrupted at any point: Entropion is inward rolling of one or both eyelid margins, causing eyelashes or periocular skin to rub directly against the corneal surface. It is one of the most painful and vision-threatening causes of epiphora and is commonly missed because the eyelid abnormality can be subtle. Medial entropion (rolling of the medial lower lid) is particularly associated with tear staining because it redirects the medial punctum and directs tears onto the facial fur rather than into the drainage system. Signs include chronic tearing, squinting, corneal pigmentation (brown discoloration of corneal surface), corneal ulceration, and rubbing at the eyes. Treatment is surgical correction. Entropion should be considered in any dog with chronic unilateral or bilateral epiphora that does not resolve with topical management. Distichiasis refers to extra eyelashes (distichia) emerging from the meibomian gland openings rather than the normal eyelid margin. In many dogs, distichia are soft and cause minimal or no irritation. In others – particularly when the distichia are stiff or emerge at an angle that contacts the cornea – they cause chronic low-grade corneal irritation, reflex tearing, and eventually corneal ulceration or pigmentation. Distichia are difficult to visualize without magnification and a veterinary ophthalmic exam. Treatment options for symptomatic distichiasis include electro-epilation, cryotherapy, and surgical lid-splitting procedures. KCS is deficiency of the aqueous tear component due to immune-mediated destruction of lacrimal gland tissue. It does not produce overflow watery tearing; instead, it produces a thick, ropy, mucoid discharge that accumulates in the medial canthus and on periocular fur, creating staining that is often mistaken for epiphora-related staining. The discharge in KCS is characteristically sticky, yellowish to greenish, and adheres to the fur rather than flowing freely. Diagnosis requires a Schirmer Tear Test: values below 15 mm/min indicate KCS; values below 10 mm/min indicate significant disease. KCS requires ongoing medical management (cyclosporine or tacrolimus ophthalmic drops to restore tear production, or lifelong artificial tear supplementation in non-responsive cases) and carries significant vision risk if untreated. Bacterial or allergic conjunctivitis produces a watery to mucopurulent discharge and epiphora from ocular irritation. Signs include redness of the conjunctival surface, discharge, and occasional squinting. Conjunctivitis is treated based on cause: bacterial conjunctivitis with appropriate topical antibiotics (requiring culture and sensitivity for recurrent cases); allergic conjunctivitis with antihistamines or topical anti-inflammatory agents. Chronic conjunctivitis can cause nasolacrimal duct scarring, perpetuating epiphora even after the inflammation resolves. Regardless of the underlying cause, regular gentle cleaning of the periocular area reduces secondary bacterial and yeast overgrowth in the moist fur. Use veterinary-formulated eye wipes or plain saline on a soft cloth or cotton pad. Wipe from the inner to outer canthus. Dry the area thoroughly after cleaning – moisture perpetuates the bacterial and yeast environment that worsens staining and causes skin fold dermatitis. Twice-daily cleaning in heavily affected dogs is appropriate during active management periods. Keeping the fur in the medial canthal region trimmed short reduces the surface area of stained fur and the reservoir of moisture. In breeds with prominent nasal folds, trimming the medial canthal fur also reduces fold-related corneal irritation. This requires grooming every 4-6 weeks for most affected breeds and is most easily combined with routine grooming appointments. Cosmetic management of staining without addressing the cause is appropriate only when the cause is confirmed to be structural and non-treatable (e.g., confirmed anatomical drainage insufficiency in a brachycephalic breed with no correctable component). In all other cases, identifying and treating the underlying cause – surgical correction of entropion, nasolacrimal duct flushing for obstruction, medical management of KCS or conjunctivitis – reduces epiphora at its source and makes cosmetic management more effective. Tear staining is just a cosmetic issue and doesn’t need veterinary attention. Tear staining is a visible sign that tears are overflowing rather than draining normally – which is a symptom, not a benign cosmetic variation. While some degree of staining in brachycephalic breeds reflects structural anatomy that is not fully correctable, new or worsening staining, unilateral staining (one eye only), staining accompanied by squinting or rubbing, or staining with thick or discolored discharge all indicate conditions that require veterinary evaluation. Entropion causes significant corneal pain and can progress to ulceration and vision loss. KCS causes progressive corneal damage if unmanaged. Treating the cosmetic appearance without addressing the cause is appropriate only after a veterinarian has confirmed there is no treatable underlying condition. Adding apple cider vinegar or certain supplements to the dog’s water prevents tear staining. No controlled evidence supports the use of apple cider vinegar, distilled water, or most marketed “tear stain supplements” for reducing epiphora or tear staining in dogs. The proposed mechanisms (altering body pH to reduce porphyrin excretion) have not been validated in peer-reviewed research. Apple cider vinegar in drinking water has a documented deterrent effect on water consumption in some dogs (they drink less because of the taste), which creates a dehydration risk. Any supplement given to change an internal physiological process to alter tear composition should be discussed with a veterinarian before use, particularly in dogs that are already taking medications or have systemic health conditions. Tear staining means the dog has an eye infection. Tear staining (reddish-brown discoloration of periocular fur) is caused by porphyrins in tears oxidizing on the fur – a chemical process that occurs with any overflow tearing, regardless of whether infection is present. The staining itself is not an infection. However, the chronic moisture that causes staining does create a secondary environment that promotes bacterial and yeast overgrowth on the periocular skin (manifesting as malodor, redness, or crust with a darker or greenish color). This secondary skin fold dermatitis does represent an infection that requires treatment. The distinction: rust-red staining of dry fur is porphyrin discoloration; malodorous, moist, reddened, or crusty periocular skin is secondary infection requiring veterinary assessment and appropriate antimicrobial treatment. The brown-red staining is caused by porphyrins – iron-containing compounds present in tears – oxidizing when they contact the fur and are exposed to air and light. In white or light-coated dogs, this discoloration is highly visible. The staining signals that tears are overflowing onto the face rather than draining through the nasolacrimal ducts into the nasal passage as they normally should. The cause of the overflow ranges from structural anatomy (very common in brachycephalic breeds with compressed tear drainage systems) to treatable conditions such as blocked ducts, eyelid abnormalities, or eye irritation. A veterinary eye exam determines which category applies and whether treatment can reduce the overflow. Use a veterinary-formulated eye wipe or a soft cloth dampened with sterile saline. Gently wipe from the inner corner (medial canthus) outward. Soften hardened crusts with a damp cloth before attempting to remove them – pulling at hardened discharge can irritate the skin. Dry the area thoroughly after cleaning. Do not use human eye drops, contact lens solution, hydrogen peroxide, or bleaching agents on or near the eyes. If the discharge is thick, sticky, or yellowish-green rather than clear, or if the area is red or malodorous, veterinary evaluation is warranted before continuing home management. Topical cosmetic products – wipes, cleansers, and topical stain-removing solutions formulated specifically for dogs – are generally safe for routine use if applied as directed and kept away from the eye itself. Read ingredient lists carefully and avoid products containing hydrogen peroxide, bleach, or harsh chemical lighteners near the eyes. Oral products marketed for tear staining require more caution: some historically contained antibiotics (tylosin); others contain unregulated supplements with unverified safety profiles. Discuss any oral tear stain product with a veterinarian before use. Antibiotic-containing products should never be used without a prescription and diagnosis. Seek veterinary evaluation for: new or suddenly worsening tear staining; staining in only one eye (asymmetric epiphora suggests a structural or disease cause rather than breed anatomy); any tearing accompanied by squinting, pawing at the eye, or apparent discomfort; thick, sticky, or discolored discharge (yellow, green) rather than clear tearing; redness of the whites of the eyes or the inner eyelid lining; visible cloudiness of the cornea; or periocular skin that is malodorous, reddened, or painful. Annual veterinary eye examinations in breeds with high staining prevalence are appropriate to monitor for treatable underlying causes. Diet has a limited and poorly understood relationship to tear staining. Some owners report improvement after switching foods, which may reflect reduced overall inflammation from food sensitivities in some dogs. There is no controlled evidence that specific ingredients cause or prevent tear staining across dogs generally. Water mineral content (filtered vs. tap water) is sometimes recommended to be changed – the theoretical basis is reducing mineral load in tears – but evidence is anecdotal. If a dietary change is being considered, discuss it with a veterinarian to ensure the new food is complete and balanced and to frame realistic expectations about likely impact on staining. Whether tear staining can be fully resolved depends on its cause. Treatable underlying causes – entropion, nasolacrimal duct obstruction, KCS, conjunctivitis – can often be managed sufficiently to significantly reduce or eliminate overflow tearing, and therefore staining, with appropriate treatment. Structural causes in brachycephalic breeds – where the anatomy itself limits drainage capacity – typically cannot be fully corrected, though surgical procedures (nasal fold resection, medial canthoplasty) can improve drainage in some cases. For most affected dogs, the realistic goal is management to minimize staining and prevent secondary complications rather than complete elimination. Tear staining is the reddish-brown discoloration of dry fur caused by porphyrin oxidation from overflow tears – a cosmetic finding. Discharge requiring evaluation includes: thick, ropy, sticky mucoid material accumulating in the medial canthus (possible KCS); yellow or green discharge (possible conjunctivitis or dacryocystitis); discharge from one eye only (possible structural or disease cause); any discharge accompanied by squinting, redness, or corneal cloudiness; and discharge that increases significantly in volume or changes character. Clear watery overflow in a brachycephalic breed with no discomfort signs may represent structural anatomy; the same volume of discharge with squinting represents a different clinical picture requiring examination. For more veterinary-reviewed guidance on dog eye health, dermatology, and breed-specific care, explore our complete Dog Health library.Crusty White Dog: Epiphora, Tear Staining Causes, and Ocular Drainage Anatomy
Veterinary Ophthalmology and Dermatology
Tear staining – the reddish-brown discoloration of facial fur beneath the eyes in light-coated or white dogs – is one of the most common cosmetic concerns owners raise and one of the most commonly mismanaged conditions in companion animal practice. The discoloration is caused by porphyrins, iron-containing compounds excreted in tears, saliva, and urine; in white or light-coated dogs, porphyrin-stained fur oxidizes to a characteristic rust-red-brown color that is highly visible. Tear staining is always a symptom, not a condition in itself – it indicates that tears are not draining normally through the nasolacrimal system and are overflowing onto the face. The causes range from normal anatomical variation in flat-faced breeds to treatable conditions including blocked nasolacrimal ducts, entropion, distichiasis, corneal irritation, conjunctivitis, and keratoconjunctivitis sicca (KCS, dry eye). This article examines the anatomy of normal tear drainage, the differential diagnosis for epiphora (overflow tearing), evidence-based approaches to management, and what cannot be safely managed without veterinary involvement.
Key Takeaways
Normal Tear Drainage Anatomy and Where It Fails
Disruption Point
Cause
Breeds at Higher Risk
Diagnosis
Increased tear production
Corneal irritation (entropion, distichiasis, foreign body), conjunctivitis, uveitis, glaucoma
Any breed
Ophthalmic exam; slit-lamp biomicroscopy
Punctal atresia or hypoplasia
Congenital absence or incomplete development of the punctal opening
Cocker Spaniels, Golden Retrievers, Poodles
Fluorescein dye test (dye should exit the nose); Jones test; dacryocystorhinography
Nasolacrimal duct obstruction
Chronic conjunctivitis causing scarring; foreign material; dental root impingement on duct; congenital stenosis
Brachycephalic breeds (shorter duct, higher obstruction risk)
Fluorescein passage test; nasolacrimal flush under sedation
Medial entropion / nasal fold impingement
Inward rolling of medial lower lid directs tears away from puncta; nasal fold skin occludes medial canthus
Brachycephalic breeds especially; Shar Peis
Ophthalmic exam; fluorescein staining to detect corneal irritation
Eyelid conformation abnormalities
Ectropion (outward rolling), macropalpebral fissure (overlarge eye opening), medial canthal pocket syndrome
Cocker Spaniels, Basset Hounds, St. Bernards; brachycephalics
Ophthalmic exam
Reduced drainage capacity (structural)
Shallow orbits and compressed nasolacrimal anatomy in brachycephalic breeds creates baseline drainage insufficiency
Pugs, French Bulldogs, Bulldogs, Shih Tzus, Maltese, Pekingese
Clinical diagnosis in context of breed anatomy
Differential Diagnosis: What Is Causing the Overflow Tearing
Entropion
Distichiasis
Keratoconjunctivitis Sicca (KCS / Dry Eye)
Conjunctivitis
Managing Tear Staining: Evidence-Based Approaches
Keeping the Periocular Area Clean and Dry
Fur Management
Addressing the Underlying Cause
Some commercial tear stain products and food additives historically contained tylosin tartrate, an antibiotic. Antibiotic use without a diagnosis and veterinary prescription contributes to antimicrobial resistance, may suppress symptoms of conditions requiring specific treatment, and is illegal without prescription in many jurisdictions. Products claiming to reduce tear staining through “natural” food additives have limited evidence for efficacy. Any oral product intended to reduce tear staining should be discussed with a veterinarian. Do not add supplements to the dog’s food without veterinary guidance – some supplements interact with medications and some marketed products have not been safety-tested in dogs.
Breeds Most Commonly Affected and Why
Breed
Primary Anatomical Factor
Additional Risk Factors
Management Focus
Maltese
White coat makes staining maximally visible; shallow orbit; nasolacrimal duct stenosis common
Hair growth pattern directs fur toward eye; small puncta
Rule out duct obstruction; regular trimming; daily cleaning
Bichon Frise
White coat; brachycephalic skull; medial entropion common
Medial canthal pocket syndrome common
Evaluate for entropion; nasolacrimal flush if indicated; regular cleaning
Poodle (all sizes)
White/light coats common; prominent eyes; punctal hypoplasia documented
Hair growth pattern; dental disease can impinge nasolacrimal duct
Dental care; punctal evaluation; trimming medial canthal fur
Shih Tzu
Brachycephalic; nasal fold impingement of medial canthus; shallow orbit
Distichiasis common; medial entropion
Ophthalmic exam for entropion/distichiasis; nasal fold evaluation; cleaning
Pug / French Bulldog
Exophthalmic eyes; nasal folds; severely compressed nasolacrimal anatomy
Significant structural component; corneal exposure keratopathy common
Management primarily structural; evaluate for corneal health; regular cleaning; surgical fold reduction in severe cases
West Highland White Terrier
White coat; high KCS prevalence in breed
Immune-mediated lacrimal gland disease
Schirmer Tear Test at every exam; KCS management if confirmed
Common Myths About Tear Staining
Frequently Asked Questions
Why does my white dog have brown stains under its eyes?
How do I clean the crusty buildup under my dog’s eyes?
Are tear stain products safe for dogs?
When should tear staining in my dog be evaluated by a veterinarian?
Can diet cause tear staining?
Can tear staining in dogs be permanently cured?
What is the difference between tear staining and eye discharge that needs treatment?
Reviewed by a Doctor of Veterinary Medicine (DVM)
Do not use over-the-counter antibiotics or unapproved additives for tear staining
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