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Have you noticed that when your dog continually licks their paws, rusty brown patches appear on their fur? Or maybe your beautiful white Maltese develops difficult-to-remove stains around their eyes.

Your dog’s fur turning pink or brown isn’t always a concern. Sometimes, though, the color change can be a symptom of an underlying health problem. Understanding the possible reasons for this discoloration can save unnecessary stress.

What Are Porphyrins and Why Do They Stain My Dog’s Fur?

Dr. Jerry Klein, Chief Veterinary Officer for the AKC, explains that porphyrin is the most common reason for pink, red, orange, or brown stains on your dog’s fur. Porphyrin is “the chemical breakdown product associated with red blood cells,” Dr. Klein says.

Porphyrins are excreted from tears, saliva, urine, and feces and are high in iron. “Iron is the nasty ingredient that especially stains white fur,” he says. This is why you often see discoloration around your dog’s eyes, mouth, licked fur, or even their rear end. While all dogs produce porphyrins, some make more than others, and the staining is more noticeable on light-colored fur.

Should I Worry About My Dog’s Fur Changing Color?

Porphyrin staining isn’t always something to worry about. However, excessive staining accompanied by certain symptoms or behaviors often indicates an underlying medical issue that may need prompt veterinary treatment.


Tear stains are particularly noticeable in certain breeds, like Maltese, Shih Tzus, and short-nosed Bulldogs. This is “because of excessive tear production and the way the tear ducts are located in the head,” Dr. Klein says.

Of course, excessive staining around the eye could also indicate eye abnormalities, allergies, infections, or injury. Head to the vet if swelling, discharge, or discomfort accompanies the staining.


Drool-prone dogs, like Saint Bernards, often have rusty-colored muzzles and beards. However, sudden excessive saliva production can indicate periodontal disease, teeth fractures, or other dental dilemmas—keep an eye out for stinky breath, bleeding gums, or difficulty eating.

Saint Bernard wearing a barrel collar laying down in the grass.
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Paws or Other Body Parts

When dogs lick their paws excessively, a build-up of porphyrins from the saliva turns the fur around the area pink or rusty red. Over time, the stains can turn a darker brown. While the staining is only unsightly, excessive licking is often a sign of an underlying medical or behavioral issue.

Reasons for Fur Staining Caused by Excessive Licking

When your dog won’t stop licking a paw or another part of their body, it’s typically because they’re trying to get some relief from pain or itchiness. Dr. Klein explains that the most common causes are “underlying skin conditions or food sensitivities.” However, your vet must be the one to rule out many possibilities. These include:

  • Itchy skin allergies: These typically relate to fleas, food, or the environment.

  • Internal diseases: Conditions that can cause skin problems include hypothyroidism, lupus, and Cushing’s disease.

  • Skin infections: Yeast dermatitis is a common culprit for excessive licking. It can become a vicious cycle when the skin and fur are wet from licking, as yeast thrives in damp conditions. Other fungal, bacterial, or parasitic infections can also lead to excess nibbling.

Bulldog rolling in the grass.
  • Wounds or foreign objects: Grass seeds wedged under the skin are difficult-to-spot culprits.

  • Painful conditions: If your dog is looking for relief from the discomfort of a disease like arthritis, they might lick the affected area.

While stress or boredom due to insufficient enrichment can trigger compulsive licking, Dr. Klein stresses the importance of consulting with a vet to rule out “an underlying medical issue before assuming it’s strictly behavioral.”

Treating Dog Fur Staining

If your dog has any concerning symptoms or behaviors accompanying their stained dog fur, the focus should be on having your veterinarian identify any potentially serious underlying causes. Your vet will evaluate your pet’s whole-body health to work towards an accurate diagnosis. “So, if a dog is constantly licking one paw, the first thing I look at is whether there’s something in the paw,” he says. “If a dog is licking two paws or all paws are brown, then I consider whether it’s a systemic problem.”

“You try to see if it’s unilateral, if it’s bilateral, if it’s all over the body, and that’s why the veterinarian is so helpful in trying to rule in or rule out problems. And then they might do individual diagnostics. Whether it’s skin scrapings to check for mites, or mange, or other things to make sure there’s no underlying bacterial problem.”

Depending on the issue, your vet might refer you to a dermatological, dental, or ophthalmic specialist. If the brown fur staining is minor and confirmed as not relating to any underlying problem, you might be happy to leave it. It might look a little unattractive, but it won’t do your dog any harm.

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If you want to try to rid tear stains, for example, tread carefully. The FDA issued warning letters to manufacturers of over-the-counter tear-stain removers containing the antibiotic tylosin. While they can reduce porphyrin staining, using them for a cosmetic issue might be controversial, given the debate about rising antibiotic resistance.

Regularly trimming the fur around the eyes and nose helps to minimize staining, as does keeping the face as dry and clean as possible. Bathing with a warm, clean cloth or cleaning pads and eye-safe shampoo is a gentle option. It might not get rid of heavy staining, but you don’t have to worry about it irritating your pet. Just dry the face with a clean towel afterward—you don’t want wet skin to cause irritation or infection.

This article is intended solely as general guidance, and does not constitute health or other professional advice. Individual situations and applicable laws vary by jurisdiction, and you are encouraged to obtain appropriate advice from qualified professionals in the applicable jurisdictions. We make no representations or warranties concerning any course of action taken by any person following or otherwise using the information offered or provided in this article, including any such information associated with and provided in connection with third-party products, and we will not be liable for any direct, indirect, consequential, special, exemplary or other damages that may result, including but not limited to economic loss, injury, illness or death.

Related article: Why Is My Dog So Itchy? Possible Causes & Treatment
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