Chronic stress, or a constant stress experienced over a prolonged period of time, can contribute to long-term problems for heart and blood vessels. The consistent and ongoing increase in heart rate, and the elevated levels of stress hormones and of blood pressure, can take a toll on the body.
Excess Tearing. The most common cause of tear stains in dogs is excess tearing or epiphora, which makes the hair and skin around the eyes damp. This can lead to the growth of bacteria and yeast. Red yeast, which produces a reddish brown discoloration of the face, is a common cause of tear stain problems.
Physical characteristics, such as long hair on the muzzle or around the eyes, deep facial wrinkles, blocked tear ducts or bulging eyes can cause tear stains. Biological causes of red tear stains include red yeast, various eye and ear infections and pH imbalance. Red tear stains can also be caused by environmental factors, such as plastic food or water bowls and minerals in the water your dog drinks. Any dog with white hair on his face, especially if he has facial wrinkles or long hair or whiskers on his face, is prone to tear staining.