Tear Staining, The Cause and Correction
Brown or pinkish brown streaks on the cheeks of dogs is a common sight. When tears overflow from the eyes, they run down the face creating wetness that provides the perfect environment for bacterial growth. As bacteria replicate they cause skin irritation and produce pigment that stains the hair brown or pinkish brown. In dark-coated dogs this colour change is of little consequence, but in white dogs tear staining is obvious.
There are two causes of tear staining. The first is tear-duct blockage. In the normal canine eye, tears leave the eye via two small openings called “puncta”. One is in the upper eyelid and the other is in the lower eyelid. Once through the puncta, tear fluid enters the tear duct that carries it to the nose. This occurs in people as well, that’s why your nose drips when you cry.
Some dogs are born with “unperforated puncta”, a condition that prevents tears from entering the tear ducts. According to Michael Zigler, a Veterinary ophthalmologist practising in Oakvill, Ont., the incidence of this condition can be as high as two percent in some small dog breeds. Unperforated puncta can be surgically opened but success depends on the rest of the tear-duct system being intact.
Many tear-stained dogs have a subtle eversion (turning out) of the lower eyelid, which compresses the puncta, preventing normal tear drainage. Surgical correction of the eyelids can reverse tears overflowing in these cases.
The second cause is excess tear production, too much volume for normal tear ducts to handle. Any eyelid deformity that causes chronic eye irritation (rubbing on the eye surface) such as an inverted eyelid or extra eyelashes along the edge of the eyelid or fur from the dog’s body, stimulates increased tear production. Many of these conditions are simply flushed out by themselves and when this does not happen, can be corrected surgically.
In most dogs a cause for tear staining can be found with a careful examination of the eyelids and tear-ducts system. Unfortunately, it’s often a combination of factors that leads to tear overflow and subsequent staining. Treatment may be frustrating and unsuccessful. Ultimately, the owner of a dog with tear staining needs to diligently keep the hair clean and other owners may just accept the staining as part of the dog’s facial colouring.
Zigler recommends trimming the facial hair regularly if it is appears too long and in the dogs eyes. Clean the skin with a water-soaked cotton ball then blot it dry. He also suggests applying zincofax, and ointment used for diaper rash, to help control skin irritation.
The authors of the book ‘Small Animal Dermatology’ recommend the application of hydrogen peroxide to stained hair, because the stained area is close to the eyes. The hair should be carefully “painted” with a cotton applicator (Q-tip) soaked with peroxide. Alternatively, a commercial product that bleaches tear stained hair back to its natural white colour can be used on a regular basis.