Symptoms to Watch for in Your Dog: Skin Pigmentation Changes

Dog skin color is determined by cells that produce pigment, melanin. Different breeds come with different skin color. What does it mean, though, when your dog's skin color changes?

Like with any change, it's important to pay attention.


Yellow skin

If your dog's skin turns yellow, it is referred to as jaundice--this is serious. Though you're more likely to notice jaundice in the whites of the eyes and on the gums, skin gets affected as well.

Jaundice is caused by deposition of pigments which are a byproduct of the breakdown of dead red blood cells in the liver. Normally, these pigments end up in bile and make their way through the digestive system and leave the body with poop.

When these pigments end up deposited in the skin instead, it means one of three things:

  • the liver is unwell and unable to do its job
  • the bile duct is obstructed
  • too many red blood cells die and the liver is unable to keep up

If your dog's skin turns yellow, they are very sick and need medical attention as soon as possible.

Blue/purple skin

If your dog's mucous membranes, tongue, or skin turn blue, this is called cyanosis--this is an emergency. Cyanosis happens when the body tissues are not getting enough oxygen. Either there is not enough oxygen getting into the body, or it's not being adequately distributed.

Either there is a problem with your dog's circulation, respiratory system,  blood, or nervous system.

If your dog's skin turns blue, they have a life-threatening problem that requires immediate medical help.

Localized or in patches

Blue/purple/yellow areas or dots

Bruises cover much of the color spectrum as they age. Bruise colors go from red to blue and dark purple, to pale green, and yellow or brown. If you sigh a breath of relief, though, don't--your dog is bleeding under their skin.

Dogs don't bruise nearly as easily as we do. Unless your dog just had surgery, finding bruises on their skin is a serious business. It means one of two things

  • their blood isn't clotting properly
  • their blood vessels are unable to contain the blood where it belongs

If you find bruising on your dog, you might be looking at serious trauma, poisoning, serious infections, auto-immune disease, cancer, and other scary stuff.

Darkening of the skin (hyperpigmentation)

Also referred to as acanthosis nigricans, darkening [and thickening] of the skin can be a result of various conditions. It can be hereditary but that's quite rare and generally happens only with Dachshunds.

Commonly, your dog's skin can darken in response to inflammatory conditions which might include anything from allergies, skin infections, immune or hormonal disorders. In any case, dark and thickened skin points to a chronic issue.

Poor thyroid function (hypothyroidism) is one of the top suspects. If combined with bad smell, there is a good chance the underlying cause is a bacterial or fungal infection. These infections can be secondary to hypothyroidism or allergies.

Red skin

Red skin is an inflamed (or hot) skin. Whether you're looking at an infection, allergies, or autoimmune disease, it will also be itchy, painful, or both.

Loss of pigment

Loss of pigment is often a cosmetic condition not associated with any serious health issues.

Depigmentation can be the result of aging or changing seasons. Some breeds, for example, are predisposed to a seasonal lightening of their nose, a condition also referred to as snow nose. There is a relatively rare condition, vitiligo, that causes the skin to lose its pigment--in patches.

In some cases, loss of pigment can be caused by infections (e.g.aspergillosis) or an autoimmune disease.

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Do you know what your dog is telling you about their health?

Symptoms to Watch for in Your Dog

Symptoms to Watch for in Your Dog now available in paperback and Kindle. Each chapter includes notes on when it is an emergency.

Symptoms to Watch for in Your Dog is an award-winning guide to help you better understand what your dog is telling you about their health and how to best advocate for them. 

Learn how to see and how to think about changes in your dog’s appearance, habits, and behavior. Some signs that might not trigger your concern can be important indicators that your dog needs to see a veterinarian right away. Other symptoms, while hard to miss, such as diarrhea, vomiting, or limping, are easy to spot but can have a laundry list of potential causes, some of them serious or even life-threatening. 

Symptoms to Watch for in Your Dog is a dog health advocacy guide 101. It covers a variety of common symptoms, including when each of them might be an emergency. 

An award-winning guide for dog parents