MECHANICAL CAUSES, DUE TO THE DOG’S BODY CONSTRUCTION
Large tear glands – larger glands produce larger volumes of tears.
Small tear duct openings – each eye has a tube running from the eye into the nasal cavity to drain the excess tears via the nose. Small openings to these ducts reduce their effectiveness and the excess spills over into the hair.
Blocked tear ducts – as for small duct openings, blocked ducts cannot remove the excess liquid from the eye. Some breeds of dog such as Poodles and Cocker Spaniels have a tendency for the drainage holes not to develop properly.
Scarring – if there has been previous infection or eye damage, tear drainage may reduce.
Hair around the eyes – if hair keeps getting into the eyes, it can wick the tears away, drawing the moisture from the eye and down to the skin.
Shallow eye sockets – particularly in brachycephalic dogs (breeds with short muzzles such as Pugs, French Bulldogs or Pekingese), eyes can bulge and protrude, sometimes so much that the eyelids never close completely, even when sleeping.
SIGNS AND SYMPTOMS OF TEAR STAINS IN DOGS
The most obvious sign of tear stains in light coloured dogs are the red marks in the hair below each eye.
These are much harder to see in darker coated dogs, and it may be that the damp hair from excessive tear production or the tears being drawn away from the eye into the fur are the easiest symptoms to see. There may be a discharge from the eye, depending on the cause of the tears, but this does not happen in every case.
If your dog has stains that are brown rather than red, particularly if there is a noticeable odour, then they may have a yeast infection that can be caused by the skin being constantly damp under the fur.
This excess iron intake can come from both your dog’s diet and from the water they drink.
In addition to causing tear stains, excess iron in the diet can also cause iron toxicity. When consumed in high amounts, this metal begins to accumulate inside organs and can easily damage the gut, liver, and brain.
Tears that contain a normal amount of porphyrin should not leave behind large, dark stains, even if there is an excess amount of tears. But if the amount of porphyrin is even slightly elevated, those extra tears will cause stains to form quicker than they would in a dog that sheds fewer tears.
As we covered above, imbalances in the body can lead to an excess of porphyrin-producing bacteria and yeast. Often, these imbalances start in the gut.
There are a number of health issues that can cause your dog to produce too much porphyrin. Some of the causes are relatively benign while others can be a sign of a serious problem.
How to Get Rid of Brown Eye Staining in Dogs
Tear stains are an unsightly problem that affects many dogs. Unfortunately, this issue isn’t just a cosmetic one.
Dog tear stains are often a symptom of a larger problem and a significant warning sign owners need to pay attention to.
If your dog suffers from constant or occasional tear stains, you’ll want to keep reading. In this article, we’ll look at the many causes of tear stains and how each can be addressed to tackle the root of the problem. By resolving the true cause of the issue and rebalancing your dog’s system, you can not only put an end to tear stains but help improve your dog’s overall health.
Tear stains are the reddish stains that appear below some dogs’ eyes. They are caused, in the most direct sense, by porphyrin–a reddish-brown pigment found in tears.
Porphyrin is produced as the body breaks down iron. This molecule is excreted through many different pathways, including the gut, saliva, urine, and–you guessed it–tears!
All dogs produce some amount of porphyrin in their tears, but some produce more than others. Dogs with light-colored fur are more likely to have visible tear stains from excess porphyrin than dogs with darker coats. No matter what color the coat, visible tear stains are a sign that your dog has more porphyrin in their system than is normal.
There are a number of health issues that can cause your dog to produce too much porphyrin. Some of the causes are relatively benign while others can be a sign of a serious problem.
For some dogs, the cause of their tear stains isn’t just about what is going on inside the body, but how their body, particularly their eyes, are structured.
Tear duct malformation, bulging eyes, shortened muzzle, and eyelid malformation can all cause excessive tear production. All of these causes are determined by your dog’s genetics. But this does not mean that every dog with a squished face is destined to live with tear stains.
Tears that contain a normal amount of porphyrin should not leave behind large, dark stains, even if there is an excess amount of tears. But if the amount of porphyrin is even slightly elevated, those extra tears will cause stains to form quicker than they would in a dog that sheds fewer tears.
If your dog suffers from entropion, has bulging eyes or a shortened muzzle, or has a tear duct issue and suffers from tear stains, there is likely something else going on inside their body that needs to be addressed.
While most people will point out structural issues as a cause for tear stains, the truth is that a predisposition to excess tear shedding acts only as an advanced warning system. In the case of structural issues, you can’t reduce the number of tears your dog sheds, but you can often treat the cause of the excess porphyrin in those tears to eliminate their tear stains.
Much like a genetic predisposition and structural malformation, irritants can cause your dog to shed more tears than normal.
Just as with structural problems, these issues alone are unlikely to cause large, dark tear stains. If your dog has tear stains and is producing more tears due to an irritant, you should work to both eliminate the cause of the excess tears and the cause of the excess porphyrin.
One of the most common causes of excess porphyrin in tears is excess bacteria or yeast in the body. That is because many bacteria and yeast produce porphyrin as part of their metabolic cycle. Just as a dog’s cells release this red pigment into their bodily fluids, so do the bacteria and yeast living inside them.
Often, tear stains are a sign that your dog has an infection in their eye, tear ducts, mouth, or other nearby location. Ulcers, conjunctivitis, untreated corneal abrasions and nasolacrimal obstructions are commonly associated with the sudden appearance of tear stains. Similarly, yeast infections in the folds of skin near the eye or inside the body can cause tear stains.
Other times, excess porphyrin is the effect of systemic bacterial and yeast imbalances rather than a concentrated infection.
Because porphyrin is created during the breakdown of iron within the body, excess intake of iron can directly increase the amount of porphyrin in your dog’s tears.
This excess iron intake can come from both your dog’s diet and from the water they drink.
Liver, egg yolk, sardines, and deep green vegetables all contain a high amount of iron. Many commercial dog foods, especially those containing few quality meat ingredients, will add an iron supplement to their recipe. Ferrous sulfate is one of the more common forms of added iron you’ll see on dog food ingredient lists.
Consuming iron-rich water can also cause an excess of porphyrin production in the body. City water is typically monitored for excess iron levels and treated to reduce levels as needed. Wellwater, on the other hand, commonly has high levels of metal in it. If this is the kind of water you use, it is worth testing it periodically for iron and other metals.
In addition to causing tear stains, excess iron in the diet can also cause iron toxicity. When consumed in high amounts, this metal begins to accumulate inside organs and can easily damage the gut, liver, and brain.
As we covered above, imbalances in the body can lead to an excess of porphyrin-producing bacteria and yeast. Often, these imbalances start in the gut.
Many harmful bacteria, including E. coli, produce porphyrin while many beneficial bacteria, such as Bacteroides, consume porphyrin(source). Bacteroides and other porphyrin-consuming probiotics are commonly found in the canine gut. These good bacteria are also responsible for keeping yeast populations in check.
If the balance of good and bad bacteria is thrown out of whack, more porphyrins will be produced and less consumed by your dog’s gut biome. This can lead very quickly to the formation of tear stains.
There are a number of factors that can cause gut bacterial imbalances, including allergies, poor diet, and stress. Antibiotic use is often associated with an initial reduction in tear stains followed by a sudden resurgence of stains. This is because these medications kill off both porphyrin-producing bacteria and beneficial bacteria. Once the medication is stopped these two types of bacteria repopulate the gut at different rates, allowing pathogenic bacteria a chance to take over.