Tear scars, more commonly called tear stains, are the reddish-brown streaks that develop on a dog’s fur beneath the inner corners of the eyes. They’re caused by an iron-containing pigment called porphyrin that’s naturally present in tears. When tears overflow onto the fur and the porphyrin is exposed to air, it oxidizes and leaves behind a rust-colored discoloration that can become permanent if left untreated. The staining itself isn’t dangerous, but persistent tearing sometimes points to an underlying eye or drainage problem worth addressing.
Why Porphyrins Stain Fur
When your dog’s body breaks down red blood cells, it releases porphyrin as a byproduct. This iron-rich pigment gets excreted through several bodily fluids, including tears. In small amounts, porphyrin washes away without leaving a trace. But when tears spill over the eyelid and sit on light-colored fur, the iron in porphyrin reacts with oxygen and produces a stubborn reddish-brown stain. This is why tear stains are far more visible on white or cream-coated breeds, even though all dogs produce porphyrin.
Common Causes of Excessive Tearing
Tear stains form when there are simply too many tears for the eye’s natural drainage system to handle. Normally, tears drain through two tiny openings (called puncta) near the inner corner of each eye, travel down a narrow duct, and empty into the nasal cavity. When any part of that pathway is blocked or underdeveloped, tears overflow onto the face instead.
Several things can cause this overflow:
- Shallow eye sockets. Some breeds have eye sockets that are too shallow to contain tears properly. The eyelid space at the inner corner isn’t deep enough, so tears spill over before they can reach the drainage openings. This is especially common in Poodles, Bichon Frises, and flat-faced breeds.
- Closed or narrow tear ducts. Some dogs are born with tear duct openings that never fully developed. Poodles and Cocker Spaniels are particularly prone to this. A vet can sometimes surgically reopen these ducts.
- Inward-rolling eyelids. When the lower eyelid near the inner corner rolls inward, it physically covers the drainage opening. Tears have nowhere to go, leading to chronic wet fur and eventually skin irritation beneath the facial folds.
- Allergies and irritants. Environmental allergies, food sensitivities, and irritants like dust or smoke can all trigger excess tear production, even when the drainage system works fine.
Breeds Most Prone to Tear Stains
Flat-faced (brachycephalic) breeds are disproportionately affected because of how their skulls are shaped. Their shallow orbits, prominent eyes, and long eyelid openings create a perfect setup for tear overflow. Shih Tzus, English Bulldogs, Pugs, Pekingese, and French Bulldogs top the list. A study found that 82% of Shih Tzus had incomplete eyelid closure, with an average gap of about 15% of the eyelid surface. That gap means tears aren’t being directed into the drainage system efficiently.
Brachycephalic breeds also face nearly seven times the risk of certain gland problems compared to dogs with standard skull shapes. And breeds like Pugs are especially susceptible to inward-rolling lower eyelids near the inner eye corner, which blocks tear drainage and leads to the chronic moisture that feeds staining. Beyond flat-faced dogs, Poodles, Maltese, Bichon Frises, and Cocker Spaniels are frequently affected due to their tear duct anatomy or coat color making stains more visible.
How to Safely Clean Tear Stains
The area around your dog’s eyes is sensitive, so the cleaning products you use matter. Look for tear stain removers that contain gentle, soothing ingredients like chamomile extract or aloe vera. These help calm irritated skin while lifting discoloration. Unmedicated eye washes can also flush away discharge without stinging.
Avoid products that contain bleach, boric acid, parabens, or bleaching agents. These can irritate delicate eye tissue and the surrounding skin. Consistency matters more than product strength. Wiping the area gently once or twice a day with a soft, damp cloth prevents porphyrin from building up and setting into the fur.
What About Antibiotic Products?
Some tear stain removers marketed to pet owners contain tylosin, an antibiotic. The FDA has issued warning letters to companies selling these products, classifying them as unapproved animal drugs. Tylosin is not recognized as safe and effective for cosmetic tear stain removal, and using antibiotics for a non-medical, cosmetic purpose carries real risks, including contributing to antibiotic resistance. Steer clear of any tear stain product that lists an antibiotic as an ingredient.
Prevention Strategies That Help
Keeping the fur beneath the eyes dry is the single most effective way to prevent staining. Trim the hair short around the inner eye corners so moisture doesn’t cling to long fur. Wipe the area daily before tears have a chance to oxidize on the coat.
Water quality plays a role too. Tap water can be high in minerals that increase porphyrin staining. Switching to filtered or bottled spring water may reduce staining over time. Avoid distilled water, which strips out beneficial minerals your dog needs.
Diet can also influence tear production and porphyrin levels. Some dogs develop more tearing on certain foods, particularly those with artificial additives or ingredients they’re sensitive to. If staining worsens after a food change, that’s worth noting. Feeding from stainless steel or ceramic bowls instead of plastic can also help, since plastic bowls harbor bacteria that may contribute to skin irritation around the muzzle and eyes.
When Tear Stains Signal Something More
Mild tear staining on a white-coated, flat-faced dog is often just a cosmetic reality of the breed’s anatomy. But certain changes warrant a closer look. If tearing suddenly increases, if the discharge changes from clear to yellow or green, if your dog starts squinting or pawing at their eyes, or if the skin beneath the stain becomes red, swollen, or foul-smelling, there may be an infection, a corneal injury, or a blocked duct that needs treatment. In some cases, a vet can flush the tear ducts under light sedation to clear a blockage and restore normal drainage.