Tear stains in dogs all you need to know - VETERINARY RESEARCH INFORMED PET SKIN & ORAL CARE

Tear stains in dogs all you need to know

Tear Stains or smelly dog eye boogies are most commonly associated with a condition known as epiphora which is characterised by excessive tearing or overflow of tears onto the fur around the eyes. Different species and breeds have been noticed to produce and lose tears at different rates, which could be due to various factors like body structure, how the body works, or if there are any health issues. Having the right amount and quality of tears is crucial for keeping our furbabies eyes healthy and maintaining good vision.

In other words: "Without enough tears or if the tears aren't good quality, it can lead to discomfort and problems with seeing clearly."

Tear staining occurs when tears overflow and trickle down the face instead of draining through the normal tear ducts. Several factors discussed earlier, such as inward-turning eyelids (medial inferior entropion), bulging eyes (breed-related exophthalmos), nose folds pressing on the eye lining and eyelid skin, tear absorption by hair rubbing against the eyes (trichiasis), and blocked or underdeveloped tear duct openings (imperforate or hypoplastic puncta), can lead to this condition.

8 top reasons why dogs can have tear stains:

1. Atopic Dermatitis: Ocular (eye) symptoms such as discharge due to blepharitis, conjunctivitis has been described by several researchers as a manifestation of atopic dermatitis.

2. Blocked Tear Ducts Obstructions or partial blockages in the tear ducts can prevent normal drainage of tears, leading to staining.

3. Eye Infections: Infections of the eye, including conjunctivitis, can cause increased tearing and staining. This presents as yellow & green discharge & red irritated inflammed eyes. Seek veterinary advice immediately if your dog presents with this.

4. Allergies: Allergies to environmental factors, food, or other allergens can lead to eye irritation and excessive tearing.

5. Ingrown eyelashes: Abnormal eyelash growth, particularly when they rub against the eye, can cause irritation and tearing. Look out for red inflamed areas along the eye rims or eye lashes.

6. Teething in Puppies: Some puppies experience increased tearing and staining during the teething process.

7. Irritants: Exposure to irritants, such as smoke or dust, can lead to watery eyes and staining if there is chronic or continuous exposure.

8. Diet: Some believe that diet can influence tear staining, and certain food additives or ingredients may exacerbate the condition in susceptible dogs

What causes brown tear stains in dogs?

The exact reason behind the colour of the staining is not fully understood yet. However, potential causes include pigments similar to lactoferrin, porphyrins, catecholamines, bacteria, yeast, or various minerals that are found in tears and saliva. The staining occurs when hair is in prolonged contact with the tears or saliva, 

Skull shape, dog breeds and tear stains.

Depending on the breeding related issues, tear stains can start early on in puppyhood. To elaborate, different dog breeds, those with short noses and flat faces (brachycephalic dogs - English Bulldogs or French Bulldogs for example) have certain body features and functions that make them more likely to get eye diseases, like brachycephalic ocular syndrome which can cause excessive tearing. Shih-Tzu dogs often experience problems like hair rubbing against the eye (caruncular trichiasis), their eyelids turning inward (medial lower eyelid entropion), eyes bulging out (exophthalmos), not being able to close their eyes completely (lagophthalmos), dry eye disease, and sores on their clear eye covering (corneal ulcers), because of how their skull is shaped, which makes their eyeballs more exposed. 

This can lead to symptoms related to dry eyes, which can cause vision loss if not treated. Shih-Tzu dogs also often have problems with their eyes, like getting sores on their clear eye covering (corneal ulceration) or experiencing dry eye disease (DED).  

Do tear stains hurt dogs?

When a dog's nose folds are big or stick out a lot, they might rub against the clear part of the eye causing watery eyes in dogs. This happens more often in brachycephalic dogs with very short noses because of how they've been bred. Symptoms include watery eyes from the rubbing,  tear staining, skin problems where the tears constantly touch due to moisture which allows yeast to breed, redness in the eye lining due to irritation (this is commonly seen in many dogs- red eye rims)  and marks on the clear part of the eye where the hairs are constantly touching. Tear stains themselves do not hurt dogs but the irritation to the eye will be very bothersome. 

Are tear stains permanent?

Tear stains usually grow out with the hair (think of when humans get their hair dyed & need root touchups) if the source of the problem is tackled. That is, as long as excessive tears continue to be produced the new hair growth will continue to be stained. 

Does tap water cause tear stains in dogs?

The surroundings where dogs live can affect their eye health. Dogs in urban areas tend to have more allergy-related symptoms compared to those in rural areas. Dogs that regularly interact with farm animals outdoors show fewer allergies. Research suggests that dogs exposed to other animals regularly during their first six months after being weaned from their mothers are less likely to develop allergies, whereas dogs raised during this time in urban settings are more prone to allergies (Hakanen et al., 2018). The quality of water in England is fairly good, so tear staining might be related to any of the above factors (environment, allergies to food, breed specific issues, external irritants etc. )

 

What ingredient in dog food causes tear stains?

Food hypersensitivity can impact the development of conjunctivitis. This condition is known by various terms such as food allergy, adverse food reaction, and food intolerance. 

A diet rich in anti-inflammatory and antioxidant components, along with medication, can enhance the symptoms of dogs with KCS (keratoconjunctivitis sicca) compared to dogs solely treated with medication and standard diet (Destefanis et al., 2016).

 

Food allergies and atopic dermatitis

It's challenging to differentiate between food allergy (FA) and atopic dermatitis (AD) in both dogs and cats. In cases of FA, which is an identification of the cause, AD, which is a clinical diagnosis, can develop. Diagnosing these conditions is tricky because they share similar symptoms, such as self-injury resulting in redness, hair loss, secondary infections, and thickened skin. Additionally, it's common for furbabies to have both food allergy and atopic dermatitis simultaneously.

 

Does chicken in dog food cause tear stains?

Chicken meat is often considered easily digestible for most dogs; however, its widespread use in dog foods has contributed to an increase in allergies to this ingredient. While there are numerous potential food allergens, chicken ranks among the most common allergens in dogs, following beef and dairy products. Consequently, many dog owners are opting to avoid pet foods containing chicken to mitigate the risk of adverse reactions. Skin diseases are prevalent issues seen in veterinary practice among cats and dogs, with Adverse Food Reactions (AFR) often being the culprit. AFR is a common problem that can manifest as skin and/or tummy symptoms in dogs and cats, encompassing food intolerance, food intoxication, and food allergy.

Does kibble cause tear stains?

The pet food industry is continuously evolving, with maintenance diets, also known as kibble shop bought diets, remaining the most popular choice. Chicken-based ingredients are widely utilised in these products due to their high palatability, affordability, and rich protein content. However, variations in nutrient composition and processing methods can impact the quality and digestibility of the protein in these diets- often found in kibble. While chicken is generally easy to digest for most dogs, its prevalent inclusion in dog foods has led to an increase in allergies to this ingredient. Despite the vast array of potential food allergens available, chicken ranks among the most common allergens in dogs, following beef and dairy products. Consequently, many pet owners are opting to steer clear of chicken-added pet foods to mitigate the risk of adverse reactions. Skin diseases are among the most frequently encountered conditions in veterinary practice for both cats and dogs,, often stemming from adverse food reactions (AFR).

 

Problems with labelling of pet food

According to regulations, manufacturers are required to clearly and consistently list either all ingredients or categories on pet food labels. Despite legal requirements and guidelines from organisations like the European Pet Food Industry Federation (FEDIAF) emphasising the need for accurate and comprehensive labelling, various studies have documented instances of mislabeling in pet food. As early as the twentieth century, research identified species-specific ingredients in dog food, revealing that over 30% of tested dog foods contained undisclosed ingredients out of thirty-one products analysed.

 

How do I reduce porphyrin in my dog's diet?

Porphyrin itself is not an ingredient that is found in dog food. The issue is here is based on potential food allergens that your dog may be sensitive to. This will require an elimination diet & introduction of single foods slowly and over a defined period of time. Your veterinarian should be able to discuss this with you in detail. 

A significant issue with mislabeled pet food lies in the ingredient list itself. Frequently, vague or intentionally ambiguous ingredients are provided [27]. Commission Regulation No. 767/09 permits the categorization of ingredients in pet foods. For instance, the term "animal fat" encompasses chicken fat, which might contain remnants of this particular species' protein. To prevent allergic reactions, this fat would need to be purified. However, while this information may be mentioned on the label, it is not always the case.

What foods prevent tear stains?

Hydrolysed diets are touted as an option to manage allergy related inflammation. he rationale for employing hydrolyzed diets in cases of food allergies (FA) is based on the concept that if proteins are broken down into molecular weights below 4–5 kDa, they become too small to bind two molecules of IgE on mast cells, which are necessary to initiate the allergic reaction in IgE-mediated allergic conditions.

Hydrolysed might still include proteins that activate beneficial T-cells responsible for managing the immune system, thus possibly failing to address hypersensitivity in animals. This also holds true for hypoallergenic diets containing peptides below 1 kDa. Surprisingly, up to 40% of dogs exhibit allergic responses to proteins of this molecular weight. It's crucial to note this information because despite the potential for hydrolyzed protein to trigger allergies, it is sometimes mistakenly suggested for feeding dogs with food sensitivities.

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