Black Spot On Dog Skin – What Could It Mean?

By Michael Tarran

December 18, 2021

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You've noticed a black spot on your dog's skin - and now you're left wondering what it could be. You're wondering if it's something serious - or, hopefully, a benign scab or something harmless along those lines.

We've all been there. Plus, we can all attest to the fact that dogs get into their fair share of shenanigans every now and again - so these things are to be expected.

But how do you know what that black spot on dog skin could actually mean?

Aside from taking a trip to the vet - the obvious is "obvious" for a reason - I'll share some of the most common causes of black spots appearing on your dog's skin.

I'm guessing you're ready to jump right in - so, let's get to it!

Hyperpigmentation

A dog sitting by a body of water

Most commonly, these black spots found on your pup's skin are a sign of hyperpigmentation.

What does that mean, you may ask?

Well, it's actually not as complex and scary as it may sound:

Hyperpigmentation is the process in which your dog's skin produces excess amounts of melanin - its natural pigment.

In fact, this is a process that also occurs in humans and can be a result of irritation, inflammation, skin infection, and other underlying causes.

It's a way for skin to protect itself after some of the aforementioned issues happen. How?

The excess melanin is supposed to provide an extra layer of protection from outside stressors - such as the sun, pollution, free radicals, and the like.

If you've ever had a pimple, especially if you have popped it - and I know you have - you know what I'm talking about here.

So, black spots or hyperpigmentation isn't a problem in and of itself - but rather, it's a manifestation of an underlying cause.

Underlying Cause Of Black Spots

A small dog laying on the the floor while the sun shines at it

We've established that for hyperpigmentation to occur, there needs to be something that triggers it.

Well, what could that be?

There are several possible options - most of them being harmless and nothing for you to worry about - but there are also some that warrant a visit to the vet and, quite possibly, some treatment.

Whether it's a yeast infection, secondary bacterial infections, Cushing's disease, age spots, allergies, or any of the other possible issues, the most important thing is:

Don't panic.

Yeast Infections

If said black dots on your dog's skin look like little specks of dirt, and your dog keeps scratching them, you might be looking at black spots caused by yeast infections.

That is actually one of the most common skin conditions in dogs, so there isn't a reason to worry - and it's usually easily solvable, too.

This kind of yeast infection is typically caused by a harmless fungus that tends to develop in dark and damp places - which is why it's usually found around your dog's groin area, in their ear canal, around their butt. Dark, warm, and wet; you get the idea.

What will help you determine if the underlying disease is, indeed, a yeast infection is if there are other accompanying symptoms - besides dark spots and dark patches, that is.

Here are some of the most common symptoms of a yeast infection in dogs:

  • Redness and itching
  • Flaky skin
  • Crusty skin
  • Thickened skin
  • Dark pigmentation
  • Recurrent ear infections

If you notice these signs, the best option is to take your dog to the vet, where they'll be able to diagnose them and give them proper therapy and anti-fungal medications, which will relieve the symptoms and eventually rid them of the infection.

Sun Exposure

Now, this is where dogs and humans are similar - although we sometimes forget that there's the skin under all that glorious fur. And even though we think that fur protects dogs fully from the effects of the sun and its rays, it's not always the case.

So, sometimes hyper-pigmentation results from the melanin building up on the skin - an attempt to protect it from the harmful UVA and UVB rays.

It's not a reason to worry, but it might be an indicator that you should include sunscreen made for dogs whenever you're spending long periods of time in the sun. The same thing applies to both you and your pup:

SPF is your BFF!

Read More: Ant Bites On Dogs – How to Quickly Recognize And Treat Them

Age Spots

An old labrador retriever laying on the floor

Another one of those harmless causes of black spots on your dog's skin is aging. Hyper pigmentation commonly affects senior dogs for the same reasons it affects humans.

You must've seen that your grandma or grandpa have similar spots on their hands, and that's because the same thing causes them both in humans and in dogs:

The skin's natural pigments build up over time and form spots on the skin.

If you notice these spots, it's a good idea to pay a visit to your vet and have them examine them closely. Even though most of the time, these spots are totally harmless, sometimes, they could be indicators of underlying skin conditions and skin problems.

Friction

Once again, much like humans, a dog's skin builds up and creates black spots as a result of friction. These spots are usually larger than spots that result from other causes - such as a specific disease - since the area of friction is usually bigger.

You'll usually notice spots like these in areas such armpits or under the hind legs; that's where friction most often occurs.

This condition isn't harmless and doesn't require any treatment.

Cushing's Disease

Moving onto a more serious cause of black spots on dog's skin, we have Cushing's disease.

It's a health condition where a dog's adrenal glands are producing higher levels of the hormone called cortisol, known as the "stress hormone." That causes a series of health problems, some of which may be as serious as kidney damage.

Symptoms of the disease are:

  • Excess urination
  • Extreme thirst
  • Loss of muscle mass
  • Thinning of the skin
  • Skin lesions
  • Hair loss (affecting the neck, flanks, and perineum)

Here's the issue with this disease:

It takes at least a year for the symptoms to show, which results in most dogs being diagnosed at a later stage of the disease when the skin problems get out of control. Also, this condition is most commonly found in older dogs, so its symptoms are often seen as normal signs of aging.

Certain dog breeds are more prone to Cushing's disease - including Dachshunds, Poodles, Boxers, Boston Terriers, and Beagles. Knowing this, if you own one of these breeds, it's a good idea to develop a monitoring plan with your vet, which will be put into place once your dog turns a certain age.

After the disease is confirmed through diagnostic tests, the vet will decide whether the affected gland requires surgical removal.

Hypothyroidism

The thyroid gland - when it works at a normal pace - regulates the body's metabolic rate. When that gland is overactive (hyperthyroidism) or underactive (hypothyroidism), certain health issues can occur.

Hypothyroidism is a metabolic disorder caused most commonly by lymphocytic thyroiditis:

The body's immune system decides that the thyroid gland is foreign and abnormal and tries to attack it. In turn, thyroid glands don't produce high enough thyroid hormone levels.

Experts still don't know what causes this - but we know that genetics certainly plays a role.

Symptoms include:

  • Weight gain not accompanied by increased appetite
  • Lethargy
  • Increased darkening of dog's skin color
  • Thinning/balding of the coat
  • Excessive shedding
  • High blood cholesterol
  • Slow heart rate
  • Recurring skin and ear infections
  • Cold intolerance

Other symptoms:

  • Lack of heat periods, infertility, miscarriages in females
  • Low libido, infertility in male dogs that haven't been neutered
  • Dryness of the eyes
  • Thickening of the facial skin

It's diagnosed through blood tests that are pretty standard in veterinary medicine.

Hypothyroidism affects dogs regardless of their breed - but it's more frequently seen in breeds like Golden Retrievers, Doberman Pinschers, Dachshunds, Boxers, and Cocker Spaniels, to name a few.

Four dogs playing in the back yard

Is it curable, you might be wondering?

Well, it's not curable - but it is treatable. So, if your dog has been diagnosed with this condition, they aren't sentenced to a lower quality of life - or a shorter life, for that matter.

Hypothyroidism is usually kept under control through oral thyroid replacement hormone.

As long as they're medicated properly - according to your vet's appropriate treatment plan - your dog can live a long, happy life!

Skin Infections

Different types of skin infections can cause hyperpigmentation to be visible on the dog's skin, too.

Pyoderma or skin infections occur in dogs due to a damaged skin barrier. Oftentimes, dogs that have skin problems such as atopic or contact dermatitis are more prone to pyoderma - since they have a damaged barrier.

Skin infection in dogs most commonly manifests through papules or pustules on the skin that might resemble pimples that appear on human skin.

Other symptoms include:

  • Flaky or crusty skin
  • Hair loss
  • Unhealthy looking fur
  • Intense itching

Vets will diagnose a skin infection usually by examining the skin, looking at previous medical history - and sometimes doing additional testing of skin samples.

The treatment usually consists of antibiotic therapy, which is sometimes combined with the use of medicated shampoos or chlorhexidine.

Secondary Hyperpigmentation

Secondary hyperpigmentation is somewhat common, and it may occur regardless of what breed the dog is - but it's more likely to occur in breeds that are prone to obesity, hormonal abnormalities, or contact dermatitis, among other things.

Unlike primary hyperpigmentation, it almost always has an underlying cause - which manifests on the dogs' skin and might be present along with other symptoms, including hair loss, thickened skin, and an unpleasant scent.

What triggers secondary hyperpigmentation is inflammation and/or friction. So, it's crucial to talk to a vet when you notice these skin changes in your dogs' skin so that they can be checked out - and any more serious issues can be ruled out.

Black Spot/s On Dog's Skin - Conclusion

You came here wondering what might be the cause of dark spots on your dog's skin - and if there is a reason for you to worry.

Well, I tried to give you the answers and ease your mind a little bit in this article - and I genuinely hope I've succeeded.

To hammer it home, I'll briefly go over everything once more.

Among the numerous reasons your dog might have dark spots on their skin, you have yeast infections - usually followed by other symptoms, like itchiness, redness, and flaky skin. They're treatable - and shouldn't cause you any worry.

Sun exposure and aging are also potential causes that warrant no worry and, oftentimes, no treatment - other than doggy SPF.

Friction can also play a role, and if this is the cause, hyperpigmentation is usually found in the armpit and groin area.

Cushing's disease varies depending on a few factors and is a serious disease, but it usually affects senior dogs and doesn't directly cause death.

Skin infections are also a potential cause of a black spot on dog skin but are easily treatable. Your dog should feel relief shortly after starting treatment.

Secondary hyperpigmentation is a result of inflammation - so, have your vet check it out if you notice the signs.

That's about it. Now you're equipped with the basic knowledge on this topic and can assume what the cause of your dog's hyperpigmentation is. However, I urge you to take your pup to the vet to get the treatment - instead of deciding for yourself.

Michael Tarran

About Me

I'm a devoted pet parent to two lovely creatures – Charlie the Cat and Jimmy the Dog – a full-time assistant pet store manager, and an animal shelter volunteer. I've gathered knowledge about pets for almost a decade, and it all started in a small store called Jack's Pets.

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