What’s the science behind excessive tearing and staining? Tear stains are common in certain dog breeds. It can be a frustrating issue for many pet owners, especially those with light-coloured dogs. These reddish-brown streaks under a dog’s eyes can be both an aesthetic concern and an indication of underlying health or environmental factors. But why do dogs get tear stains? Let's dive into the science behind it.

What Are Tear Stains?

Tear stains, also known as epiphora, appear as darkened fur beneath a dog’s eyes due to an overflow of tears. While mild staining is natural in some breeds, excessive staining can indicate a deeper issue. The characteristic reddish-brown colour is due to porphyrins, iron-containing compounds that are excreted through a dog’s tears, saliva, and urine.

Porphyrins are naturally produced as a byproduct of red blood cell breakdown. In dogs, excess porphyrins are expelled through bodily fluids, including tears. When tears remain on the fur for prolonged periods, they oxidise and cause the reddish-brown discolouration commonly seen in tear stains. Certain factors can increase porphyrin production or retention, leading to darker and more persistent staining.

Common Causes of Excessive Tearing and Staining

1. Genetics and Breed Predisposition 

Some breeds are naturally prone to tear staining due to their facial structure. Brachycephalic (flat-faced) breeds like Pugs, Bulldogs, and Shih Tzus often have shallow eye sockets and misaligned tear ducts, leading to frequent tearing. Similarly, small breeds like Maltese, Poodles, and Bichon Frises are genetically predisposed to narrow or blocked tear ducts. 

2. Tear Duct Blockage or Poor Drainage

If the nasolacrimal (tear drainage) ducts are too small, blocked, or malformed, tears cannot drain properly, leading to overflow and staining. This can be congenital (present at birth) or develop later due to infections, inflammation, or scarring.

3. Eye Infections and Irritations

Bacterial infections, conjunctivitis, or irritants like dust and smoke can cause excessive tearing. Inflammation of the eyes prompts increased tear production as a natural defence mechanism, leading to staining.

4. Allergies and Sensitivities

Just like us, our dogs can have allergic reactions to environmental allergens (pollen, dust mites), food ingredients, or chemicals in grooming products. Allergies can trigger excessive tear production, making stains more pronounced.

5. Diet and Nutrition

Poor-quality dog food, especially those with artificial additives, preservatives, or low-quality proteins, can contribute to excessive porphyrin excretion and tear staining. Some owners report improvements when switching to a high-quality, minimally processed diet with natural ingredients.

6. Water Quality

High mineral content in tap water, particularly iron and other heavy metals, may increase porphyrin levels in a dog’s tears, leading to darker stains. Many dog owners find that using filtered or purified water helps reduce staining.

7. Dental Issues and Oral Health

Dental infections, gum disease, or teething in puppies can contribute to excessive tearing. The close proximity of the eyes to the oral cavity means that infections can cause inflammation, affecting tear production and drainage.

8. Stress and Hormonal Imbalances

Stress, anxiety, and hormonal imbalances can also play a role in excessive tearing. Dogs experiencing high cortisol levels (stress hormones) or thyroid imbalances may exhibit increased tear production.

Preventing and Managing Tear Stains

Understanding the underlying cause of tear stains is key to reducing them. Dog tear stains are common and can be influenced by various factors, including breed, age, and gender. The causes range from temporary (acute) to long-term (chronic), with some requiring medical attention, such as infections that need treatment. Here are some strategies to prevent and manage tear stains:

Keep the Eye Area Clean

Regularly wipe your dog’s eyes with a damp, soft cloth or pet-safe eye wipes to remove excess tears before they cause staining. Try the Eye Envy Tear Stain Remover Starter Kit for Dogs. This set contains a two-step treatment and has all the tools needed to effectively remove unsightly tear stains. When you are constrained for time, for a quick eye clean-up, use an eye wipe like this Earthbath Hypoallergenic Eye Wipes for Dogs and Cats.

Choose a High-Quality Diet

Avoid artificial additives and opt for a fresh, balanced diet that supports overall health. Do take note that a raw diet can potentially reduce or worsen tear stains, depending on the individual dog and the diet's composition.

A raw diet can help reduce tear stains by eliminating common allergens and inflammatory ingredients found in commercial kibbles, such as grains, artificial preservatives, and fillers, which may trigger food sensitivities and excessive tearing. Additionally, raw diets rich in high-quality proteins, probiotics, and natural enzymes promote better gut health, reducing inflammation and excessive porphyrin production. The higher moisture content in raw food also improves hydration, helping maintain proper tear consistency and minimising eye irritation.

Conversely, raw diets high in organ meat and iron can increase porphyrin production and make tear stains more noticeable. Additionally, red meats like beef are naturally high in iron, which may contribute to darker staining due to porphyrin oxidation. In such cases, try switching to lower-iron proteins like chicken, turkey, or fish.

Some dogs may also experience a temporary detox phase when transitioning to raw, during which their body expels built-up toxins, resulting in increased tearing. However, in such a scenario, the staining is temporary and the condition typically improves after a few weeks.

Provide Filtered Water

Using filtered water may help minimise porphyrin buildup. Filtered water is often recommended for dogs with tear stains because tap water can contain high levels of minerals, like iron, which can contribute to the staining around a dog's eyes when they are excreted through tears.

Check for Allergies

Identify and eliminate potential allergens, whether in food, the environment, or grooming products. Shampoo or other grooming products getting into the eyes during grooming can cause irritation and tearing. Food sensitivities are a common culprit behind tear staining. Inflammatory responses triggered by problematic food compounds can increase tear production and worsen staining. One way to identify potential food sensitivities is to conduct an elimination diet. Gradually removing and reintroducing specific food items can help to pinpoint those that are problematic.

Use Natural Supplements

Probiotics and omega-3 fatty acids may support eye health and reduce inflammation. Probiotics and digestive enzymes may help restore and maintain a healthy gut microbiome, promoting a healthy gut microbiome, which can reduce inflammation and potentially lessen the production of porphyrins. Omega-3s can help reduce inflammation that causes watery eyes and tear stains. It helps to reduce inflammation and tear staining in dogs by promoting eye health. Omega-3 prevents dry eyes and promotes strong cell membranes in the eye. Adding an omega-3 supplement like the Dom & Cleo Wild Fish Oil Supplements For Dogs & Cats into your dog’s diet may help to improve tear stains. Dog-friendly eye supplements that contain lutein and zeaxanthin, like the Vetter Lutein Eyes Health Supplements for Dogs & Cats can help support the dog’s eye health by lubricating mucous membranes, preventing dry eyes and tear stains. 

Grooming & Trimming

Keeping the fur around the eyes short can help prevent tear accumulation and bacterial growth. You or your groomer can check for ingrown hairs and keep the hair trimmed short around the eyes. If there is no excessive staining, a clean cloth and warm water can be used to wipe your pet’s facial area.

When to See a Vet

If your dog’s tear stains suddenly worsen, appear alongside eye redness, swelling, or discharge, or if your dog seems to be in discomfort, consult a veterinarian. In some cases, medical treatment such as antibiotics, tear duct flushing, or even minor surgical corrections may be necessary. Tear stains in dogs are more than just a cosmetic issue; they often signal underlying health or environmental factors. Understanding the root cause behind tear staining can help pet owners take effective steps to manage and prevent the problem.

KATHERINE KHOO

Katherine is a Pet Nutrition Specialist and GDP’s Pet Wellness Advisor. She is committed to helping pet owners make informed dietary and lifestyle choices in nurturing healthy pets. Katherine is also a practicing Nutritional Therapist (human nutrition) and has been helping hundreds of clients to heal naturally with nutrients.