Many dog owners report that their dogs' fur changed color after a surgery or injury causing a dog's fur to turn darker. What happened? Any changes in a dog's fur color are worth investigating as sometimes they can be a sign of something not being quite right. Here are some causes of coat color changes in dogs.

The Process of Maturing

If you have a puppy who is changing coat color as he's turning 8 or maybe 12 months old, chances are, his coat color changes are due to maturing. 

This can vary a bit among breed. For instance, poodles are often born one color and tend to lighten or get  some 'frosting' as they mature. Airedale terriers sometimes have grey mixed with the black on the saddle portion of their coats and this can cause some gray color to mix in.  A Labrador puppy may have a lot of black on the top of the head that may turn to brown once around the age of 1 year old.

Puppies go through a temporary shed, leading them to losing their puppy coat.  Occasionally, darker skin color may also arise around the beginning of hormonal changes (female dog going in heat).

The most important thing is that the color change isn't associated with any signs of skin problems such as the presence of lesions, hair loss or frequent itching, explains veterinarian Dr. John.

Did you know? Dogs boasting an agouti coat color are known for changing a lot as they mature. The agouti coat is made of hairs that display alternating bands of colors. It is the color of the coat of wolves, elkhounds and wild mice, squirrels and rabbits. For this reason the agouti coat color is often referred to as the"wild coloring."

The Aging Process

Humans are not the only ones to age, turns out, dogs age too, and when they do, their fur undergoes changes just as it happens in humans. 

Dogs may not get white hair to the extent of humans, but it's normal to see some graying of the muzzle. As a dog matures, it's  therefore quite common for his darkly pigmented coat to attain a lighter color. 

This loss of pigmentation in the dog's coat occurs because pigment takes quite a good amount of energy to make and the body focuses on tending towards other more important needs.

 As long as there is no irritation, redness or undesirable smells, there should be nothing to worry about.

Some Minor Causes

Just as people's' hairs tend to lighten during the summer months, Rover's hairs may bleach slightly too, explains veterinarian Dr. Christian.

Shaving a dog's coat may also cause the hair to become softer and prone to color changes. Generally lighter hues are seen after repeated haircuts.

The fact that clipping affects texture, and color of a dog's new coat coming through, has triggered some groomers to start adding a disclaimer to inform their clients of the possible coat color changes associated with shaving a dog's hair.

Damage to hair follicles from a previous injury may also cause coat color changes in dogs, explains veterinarian Dr. Loretta. In the areas of previous trauma such as a surgical incision site, a clipper burn or even a hot spot, the hair may therefore grow darker in color. 

This occurs because cells containing melanin, rush to the trauma site as part of the inflammatory process, which turns the skin and hair a darker color, explains Sandy Blackburn in the book: "The Everything Dog Grooming Book."

Hormones Out of Whack

Changes in a dog's coat color and texture can be an indication of hormonal problems. Hypothyroidism, a medical condition where the dog's thyroid levels are low, causes several coat changes and a change in pigmentation may be one of them.

Along with a pigmentation changes, hypothyroidism can cause hair loss, brittle hair, secondary skin infections and other symptoms such as lethargy, obesity and a slower heart rate.  It's not a bad idea to have the vet run a comprehensive blood panel to exclude this condition.

A Matter of Stains

Sometimes dog owners report that the fur on their dog's face is of a different color. This is mostly seen in dogs with candid white coats that attain pink, red or brown colors around the eyes and mouth area.

 In this case, the colors are really stains that come from the dog's saliva and tears. The cause of these stains on a dog's fur are natural chemicals called porphyrins which are found in a dog's tears and saliva, explains veterinarian Dr. Dave.

Considering that dogs tend to lick several areas of their bodies, it's not surprising for other parts of the body such as feet, legs and sides to assume a brownish tint from the residue of saliva. 

While the issue may be strictly cosmetic, a veterinarian should be consulted as the staining can be caused at times by underlying medical problems such as blocked tear ducts, in the case of tear stains, or periodontal disease, in the case of mouth stains.

Allergies or skin problems should also be ruled out as these can trigger excessive licking that results in brownish stains on other parts of the dog's body.

Did you know? If your dog is wearing a collar with tags, sometimes the metal in the tags may cause a color change in the dog's fur from the oxidizing effect of the metal.

This dog's fur color change around the eye area is due to porphyrins found in a dog's tears.

This dog's fur color change around the eye area is due to porphyrins found in a dog's tears.

Loss of Pigmentation

"My dog's coat color has changed drastically and some areas on the face have turned white, what can this be?" Such drastic coat changes may be triggered by a medical condition known as vitiligo

In this case, the loss of pigment mostly affects the dog's nose, lips, and face and it can be temporary or even permanent.

What happens is that, melanocytes, the cells responsible for giving pigment to the dog's coat die or no longer function, explains veterinarian Dr. Gabby. This condition can be caused by an autoimmune disease, genetic factors or a virus, but sometimes its exact causes remain unknown.

Rottweiler dog with vitiligo (notice the white hair areas under eyes) Source: Wikimedia CC BY-SA 3.0

Rottweiler dog with vitiligo (notice the white hair areas under eyes) Source: Wikimedia CC BY-SA 3.0

Did you know? White isn't really considered a coat color as white hair isn't caused by pigment but rather a lack of pigment.

Now That You Know...

As seen there are many possible reasons why dogs' fur change color. If you are in doubt or if your dog is showing signs of of problems such as excessive itching, hair loss or presence of lesions, consult with your vet. A referral to a board-certified veterinary dermatologist may turn insightful for complex cases. 

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