Why Does Dog Skin Go Black?

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Have you ever noticed how your dog’s belly is black in summer, but pink in winter? Or maybe you’ve noticed black patches of dog skin in the armpits or groin.

Why does this happen: Why does dog skin go black?

The Answer is….Melanoderma!

Dog skin darkening is due to increased production of the pigment, melanin. When this dark pigment is laid down in the skin it has a special name, which is ‘melanoderma.’

But this raises a second question: What causes melanoderma?

The answer is ‘Lots of things‘ from the pup’s genetics to skin infections, inflammation, or even cancer.

Why Does Dog Skin Go Black?

Let’s tickle those tummies to look at why black skin on dogs happens.

Hair protects the skin, shielding it from the sun (like wearing a T-shirt) or contact with allergens. One of the reasons we tend to notice black bellies, is the dog’s fur is thinner here.

Thus, if something is going to irritate the dog, you’ll see signs first on the belly. This is also true for other areas where the fur is thinner, such as the armpits or groin.

Skin Inflammation as a Cause Black Skin on Dogs

Skin has limited ways to protect itself, but one of them is melanin production. Just as a suntan protects our skin from the sun, so dark pigments are a protective reaction in dogs’ skin.

Yes, dog skin can darken in response to the sun (especially if the dog sunbathes belly up!) But more commonly, it’s inflammation that’s responsible for the insult. The causes of inflammation include:

  • Bacterial Infections: The skin’s immune system activates to fight off bacteria. When the dog has a long term, low grade skin infection, this leads to inflammation and results in melanoderma. Those dogs with naturally greasy skin or disorder of skin turnover (such as seborrhea) are especially vulnerable to bacteria infections.
  • Yeast Infections: Think of this as the doggy equivalent of athlete’s foot. An yeast overgrowth causes itching, challenges the skin’s immune system, and causes inflammation.
  • Parasitic Infections: Anything that causes itchiness will cause scratching and skin inflammation. Examples are the humble (but very irritating flea) through to fox mange or the demodex mite.
  • Allergies: Allergies cause intense itching and irritation, which leads to licking and scratching, and constantly inflamed skin. If the dog has a seasonal allergy, such as to pollen, then the skin may be darker in the summer months.

In most of these cases the dog will give you clues that something isn’t right. This may be obsessive licking or scratching, or a skin that feels greasy and unpleasant to stroke.

Genetic Issues as a Cause of Black Skin Disease

There are a handful of conditions where the pup inherits genes for melanoderma or black skin from their parent. This often goes hand in paw with hair loss. A poor coat and black skin, especially in breeds prone to these conditions, should raise a strong suspicion.

  • Alopecia X in Pomeranians
  • Melanoderma and alopecia in Yorkshire terriers
  • Acanthosis nigricans in Dachshunds
  • Hyposomatotropism in Chow Chows, Pomeranians, and Samoyeds

These conditions can be improved with medicated shampoos and a good diet to promote good skin condition and make it more resilient.

Hormonal Issues causing Black Skin on Dogs

For some dogs it’s their hormones which causing skin darkening. The skin changes are usually only part of a bigger picture, so be alert for other signs the dog isn’t quite right.

  • Cushing’s Disease: An overproduction of steroid by the body causing skin changes along with increased thirst and a pot belly
  • Underactive Thyroid Glands: Hypothyroidism causes a lack of energy and weight gain just by looking at a biscuit

Black Skin and Cancer

A patch of coal-black skin, especially if the area is slightly raised or intensely itchy, should be taken seriously. Skin melanomas are typically dark black (although atypical non-pigmented melanomas can occur) and require urgent attention from a vet.

Black Skin on Dogs: Keep Calm and See the Vet

So what does it mean if your dog’s skin develops dark patches?

Not all causes of a dog’s skin darkening are serious. It could be something as simple as the time of year or a mild allergy. However, black skin on dogs is often a sign the skin is trying to protect itself.

It might be the dog has a condition which needs veterinary treatment such as:

  • A bacterial or fungal skin infection
  • A severe itch due to parasites
  • A nasty allergy
  • A hormonal problem

Another (thankfully rare) possibility is skin cancer.

In short, only your vet can make a definitive diagnosis. Keep calm and pay them a visit to get the low down on why your dog’s belly is black.

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