While dogs don’t shed tears when they are sad or overjoyed, they do produce tears for a number of reasons. Many people will be familiar with the reddish-brown tear staining that can occur under a dog’s eyes, particularly in small-breed dogs. For our canine friends, these tear stains can be uncomfortable, or a sign of underlying eye disease.
As dog owners, the stains can be unsightly and puzzling. While most causes of tear stains are harmless, it might be wise to rule out other eye diseases that cause tearing. So, what does cause the tear staining, and what can we do about it?
What Are Tear Stains in Dogs?
To function properly, the eyes must be kept moist. Tears, which are comprised of water, oil, and mucus, provide the necessary moisture to protect the eye. Some dogs produce excessive tears. In the vet world, the technical name for excessive tearing is epiphora.
Tear staining occurs when the tears dry on the fur beneath the eyes. The classic reddish-brown color of dog tear stains is caused by an iron-containing dye molecule called porphyrin. This molecule is secreted in tears, as well as in bile and saliva. If excessive tear production occurs, the porphyrin in the tears will stain the fur as it dries.
While tear staining is easily recognizable in dogs with white coats, it can be harder to detect in dogs with dark or black coats. Dogs with short noses, large eyes, flat faces (such as the brachycephalic breeds), white fur, or congenital tear duct issues are more likely to develop tear stains, though any dog can be affected by epiphora.
Why Are Tear Stains Problematic?
Most causes of tear stains in dogs are not problematic. Many dogs, especially the small, white fluffy dogs, are just teary and always will be. They can live with this problem and do not feel any discomfort or self-consciousness.
There are three main reasons why tears and tear-staining may be an issue:
- The tearing is caused by eye disease.
- The tearing is not cleaned, and the stained or crusty area becomes infected.
- The tear-staining is unsightly for dog owners.
What Are the Signs of Tear Stains in Dogs?
There are several signs of tear staining in dogs:
- Reddish-brown discoloration of the skin and hair beneath the eyes
- Dried brown or dark crusty material beneath the eyes
- Redness of the eyes
- Visible tears and moisture around the eyes
- Swelling of the skin around the eyes
- Discomfort when touched around the eyes
What Are the Causes of Tear Stains in Dogs?
You may have noticed that when you cry, you develop a runny nose. This is because the tears produced by the eyes typically drain into the nose via the nasolacrimal duct, a narrow passage that cannot be seen by the naked eye. Dogs have nasolacrimal ducts just like us.
For most dogs, epiphora and subsequent tear staining is caused by variations in anatomy that cause tears to drain onto the face, rather than into the nose via the nasolacrimal duct. In some dogs, this duct has become blocked, leaving the tears nowhere to go but onto the face.
As we have touched on, the staining itself is caused by the drying of porphyrin, an iron-based molecule that is excreted in tears. As the tears dry, the porphyrin discolors the skin and hair.
In some dogs, excessive tear production and tear staining are not related to congenital factors and nasolacrimal ducts. Any sore or injured eye can produce tears in excess.
Pathological causes of epiphora include:
- Trauma to the eye
- Corneal ulcers (injury to the clear surface of the eye)
- Allergies (typically to environmental pollens and grasses)
- Lumps on the eyelid or around the eye
- Entropion (inward rolling of the eyelids due to excessive skin)
- Distichiasis (extra eyelashes that have grown in the wrong place on the eyelids)
Diagnosing Tear Stains in Your Dog
To begin, your vet will take a thorough history. They may ask you how long the tear staining has been occurring, if your dog is showing any signs of discomfort, and if any at-home treatments have been attempted.
After performing a thorough physical examination, the veterinarian will focus on the eyes. Several in-house tests can be conducted, including an ophthalmic exam using a special device, measurement of tear production with the Schirmer tear test, tonometry to measure eye pressures, and the application of fluorescein to check for ulcers on the eye surface. If all tests show normal results, it can be concluded that tear production is not problematic or indicative of significant eye disease. The text is missing. Please provide the text that needs to be rewritten. following sentence in a different way:
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