Black Spots on Dog’s Skin, Belly and Gums – Causes & Treatment

Black spots on dog skin

The appearance of your dog’s skin can tell a lot about his or her health. Your dog may be losing a lot of hair or itching all over. This may indicate an allergy or pest (flea) infestation.

But what does it mean when there are black spots on the dog’s skin? Dark marks and patches are a common symptom of sunburn, but they can also present as a symptom of a serious disease.

  • Dark spots can form on the belly (abdomen area) and will be easily visible if your pet is white.
  • In some instances, the spots can form on the dog’s tongue or even gums.
  • The eyes may also be affected.

Unlike human beings, dogs will not tell you they have fallen sick when they do so. When your dog develops black spots, there are a few important aspects you need to be aware of.

What are black spots on dogs?


Black spots can appear anywhere on the body of your dog such as the back, tail, legs and so on. They can also appear on the skin or the fur in various sizes and depth of color.

In most cases, such an occurrence is a harmless case of hyper-pigmentation. Melanin, the natural black pigment found in mammals, an increase in the amount to cause hyperpigmentation in animals. This is common especially among dogs with a white coat of fur such as the Maltese breeds.

While hyperpigmentation is common on the skin and fur of dogs, it can also occur on the nails of your dog.

You can tell black spots from hyper-pigmentation and those caused by other issues by as they are flush with the skin. This means they are on the same level with the rest of the skin and have no fluid, crusting or swelling.

Unless you have observed any specific signs of an infection from your dog, the black spots are a natural occurrence that you should not worry about.


Among the signs and symptoms that may accompany the black spots on your dog are listed below. If you observe any of them, see your vet as soon as possible.Black-spots-on-dogs-gums

  • The loss of hair akin to baldness with a black patch left on the skin is one of the main signs of problematic black spots.
  • Any black dots or patches on the skin.
  • At times, you may take note of a foul funky smell from your dog accompanied by seborrhea (dandruff in dogs). The two symptoms can also be noted together with heavy dandruff on the skin. If you observe such, it would be due to a yeast infection of your dog’s hair follicles.
  • Assuming you clean your dog often (at least weekly), you will notice speckles around the genitals or on the underbelly. These tiny black dots on your dog are not to be there if it is healthy.
  • Your dog could lose its hair especially on the upper back and the tail when it has an infection. The causes of this loss of hair are many although none of them is safe enough to ignore.
  • When symptoms occur in a cyclic manner, it is often easy to confuse them with allergic reactions to grass and the weather yet it could be an infection. Symptoms may be present in the Spring but are not there in the Fall. What most don’t know is that allergic reactions in dogs are quite a rarity while infections are commonplace.
  • When your dog lacks energy and enthusiasm (lethargy) besides losing its appetite, there is always an underlying issue to deal with.
  • You can observe the dog licking or chewing its feet often. If you observe the chewing and a rusty-red and dark kind of hair between its toes, it would be an infection. Of note is that a dog rarely chews its feet without an underlying issue. Either the foot is infected or the toenail is broken or another reason.
  • Your dog may also often scratch its ears and shake its head. While these too are common dog habits, they mean something else when they occur too often. Either it is an infection or ear mites (or other reason).
  • The skin can also be thickened, scaly and crusty when an infection sets in.
  • Lumps on the skin. These lumps may extend beyond the surface of your dog’s skin.
  • Bumps on the skin that have fluid in them.
  • Bleeding patches on the skin.
  • Frequent scratching due to itchy parts on the skin.

The presence or absence of these symptoms will depend on the type of infection your dog is suffering from. For this reason, always have the dog checked when you notice any of them.


There is a myriad of causes for black spots on your dog. Some are easy to deal with while others will require patience on your end to do away with. Again, unless you see any symptoms accompanying the black spots, you need not bother with it since it is a natural and harmless issue.

By ‘common causes’ it means those that you do not need to worry about or can solve with home remedies on your own. These include:

1. The sun

Melanin protects the skin from the harmful ultraviolet rays of the sun. These rays are known to cause skin issues the most dreaded of which is cancer of the skin. The same can occur in dogs and other animals.

When exposed to the skin, the skin tries to protect itself by secreting melanin in large amounts. That explains the aspect of skin tanning in humans.

The same aspect occurs in dogs and is known as hyper-pigmentation. The dog will secret melanin when exposed to the sun for long periods to protect its skin. You will notice that the black spots develop on the upper parts of the dog’s skin.

If this is the case and other are no other symptoms, you have nothing to worry about.

2. Aging

Called age spots, aging can also lead to black spots on the body of your dog. These ones are also not harmful in any way although they may dry up occasionally.

As long as your dog is well-taken care of, you need not worry about these spots.

3. Friction

If you see the black spots in areas with joints or those that move such as under the legs, the armpits, elbows, hocks or other parts, it is often due to friction.

While normal and harmless, it may mean that the dog hurt itself and needs care.


The other causes of black spots on your dog, (and the ones you should worry about), are diseases. In this class are many diseases all of which exhibit one or several of the symptoms above.

4. Allergies

When your dog is allergic to certain things in its environment, it may exhibit various signs one of which are black spots on the skin. Other symptoms of allergic reactions in dogs include:

  • The dog itches itself around the rectal area. It will lead to scooting.
  • Frequent burping and flatulence.
  • Wheezing and coughing.
  • The hair around the paws and toes will be discolored with the skin reddening.
  • Increased bowel movement accompanied by vomiting and diarrhea for food allergies.
  • Red and watery eyes, sneezing and running nose.
  • Biting and licking the body in areas such as paws, feet and the tail.
  • Loss of hair, raised welts and rashes due to frequent scratching.

The most common types of allergies in dogs include:

  • Flea allergies
  • Contact allergies
  • Airborne allergies (to dust mites, molds, mildew, weeds, pollen)
  • Food allergies

While allergies cannot be done away with, they can be managed.

5. Hemorrhage

Hemorrhage is simply called bleeding and often medically called vasculitis owing to its reference to the blood vessels of the body.

When your dog is bruised, the blood capillaries below the skin will be ruptured. As they bleed out, the blood will be trapped below the skin. This will lead to skin discoloration and a dark patch just above the trapped blood.

Often, the black patches will clear away on their own. If they hang around for up to a few weeks, you need to see your vet for a checkup. You need to be sure that it is actually a bruise in the first place.

6. Hypothyroidism

Hypothyroidism is a case in which the thyroid glands perform less than expected and thus release less of the thyroid hormone than it should be available. Being responsible for the metabolism of the body, the little amount of the thyroid hormone means that your dog’s metabolism will be less than optimal.

Hypothyroidism is common to all breeds of dogs. However, there are some breeds with a history of having more cases of hypothyroidism than others. They include:

  • Dachshunds
  • Cock spaniels
  • Boxers
  • Doberman
  • Irish settlers
  • Golden retrievers

If you have a female dog that has been spayed or a male one that has been neutered, they are both more likely to develop hypothyroidism compared to before the procedures were carried out.

The symptoms of hypothyroidism in dogs include:

  • Loss of hair on the trunk, tail and the back of its hind legs
  • Flaky skin
  • Dull coat
  • Black patches on the skin
  • Repetitive infections of the toenails and ears
  • Lethargy
  • The loss of muscles
  • A slowed heart rate
  • Weight gain
  • Infertility when the disease is not treated on time.

The one trait setting hypothyroidism aside is that the skin without hair will rarely get itchy.

To treat the dog from canine hypothyroidism, thyroid supplements are to be taken on a daily basis. While the drug being used for this condition is Levothyroxine (L-thyroxine), the dosage will differ with each dog affected.

7. Cushing’s disease

Cushing’s disease is also called Cushing’s syndrome or hyperadrenocorticism. This is a condition in which the adrenal glands of your dog will start overproducing certain hormones in the body. Among the causes of this condition include:

  • A pituitary tumor.
  • A tumor in your dog’s adrenal gland.
  • Too much use of some drugs such as steroids.

Of the three causes, the most common (up to 90 percent of all cases) is the presence of a tumor in the dog’s pituitary gland.

Among the symptoms of this disease include:

  • The dog will have an increased appetite.
  • It will also experience increased thirst and will thus consume large amounts of water.
  • The dog will have frequent urination.
  • It will lack enthusiasm and be generally fatigued (lethargy).
  • Its fur will have an unhealthy look.
  • Pot-bellied appearance (distended abdomen).
  • There will be dark spots on its skin.

The available treatment methods available for this disease will depend on its cause. Whether it is caused by steroids, a tumor in the adrenal gland or one in the pituitary gland, the doctor will recommend any of the following:

  • Surgery to remove the tumor in the affected glands.
  • Selegiline hydrochloride
  • Mitotane
  • Trilostane
  • Refrain from using the steroids any more.

The good news is that the disease is treatable and your dog will be fine afterward.

With proper care, all these health conditions can be managed well with some being treatable. If you are not sure whether the condition is a disease or a normal issue, simply let your vet decide that for you as they have the knowledge and experience to tell the two apart.

Dirt-like black spots

When your dog has black spots on its skin but the spots appear like dirt, chances are high that it has a yeast infection. The likelihood of having a yeast infection go up when the spots are found around the genitals.

It is not easy to tell yeast infection spots from those caused by hyper-pigmentation since they are both flushes with the skin. The main differences are that:

  • Yeast infection spots look like dirt while those from hyper-pigmentation are clean.
  • Yeast infection spots are first observed around the groin area (around the genitals) before spreading to the other parts of the body.
  • Spots caused by hyper-pigmentation do not have any symptoms unlike those from a yeast infection.

In dogs, yeast infections occur due to the overgrowth of the fungus Malassezia pachydermatis. This fungus is present in the body and found in dogs in harmless amounts in areas like the rectum, the vagina, the inter-digital area (between the toes), anal sacs, and the ear canal.

The fungus will overgrow when the immune system of the dog is weakened. The conditions which favor the overgrowth of the of this fungus include:

  • Allergic attack
  • Bacterial infections
  • Overuse of antibiotics

The symptoms of a yeast infection in a dog include:

  • Itching
  • Foul smell on the skin especially when widespread
  • The skin will appear oily and crusty and scaly
  • Licking and scratching of specific areas
  • Loss of hair
  • Black spots

Canine yeast infections can either be localized to areas such as genitals, the muzzle, toes, anal area and the ears or be spread on the body.

When you aim to treat the yeast infection, ensure you have had the cause of the immune suppression before treating it. Among the most used treatment methods include:

  • Use of shampoos with either 1% chlorhexidine, benzoyl peroxide, sulfur and ketoconazole. These shampoos provide conditions which are unconducive for the yeast to thrive.
  • Localized cases of yeast infections can be treated with miconazole creams.
  • Injections and oral medications can be used especially when topical treatments have failed or the infection is severe.

With focus on the health of the dog, you will rarely miss out on an issue requiring the attention of the doctor.