Why is My Dog Getting Black Spots On His Belly?

If black spots appear on your dog’s belly, you’re not alone. Are the spots a sign that something is wrong or just something that happens naturally to some dogs?

Your dog could be getting black spots on his belly due to aging, allergies, fleas, and mites, or a yeast infection. There isn’t much that you can do about the first one. But if your dog presents other symptoms, it’s best to consult a vet.

Read on to learn about the causes and signs of those black spots so that you know if you should call your vet or simply get used to the new dog “freckles.”

Your Dog Is Aging

Dogs sometimes develop black spots as they age, a process known as hyperpigmentation. Since this process happens over time, we often don’t notice the spots until they become dark enough, like one day noticing we need glasses or that our hair has turned gray.

If your dog has no other symptoms associated with a skin problem, wait until your next vet visit. But scratching or biting the spot, an unpleasant odor, or hair loss are more serious concerns.

Hyperpigmentation Might Be an Issue

Hyperpigmentation is caused by excess concentrations of melanin, which is the natural pigmentation of the skin. The color of your dog’s fur, eyes, and skin are affected by melanin, which plays an essential role in protecting the skin from UV light.

By itself, hyperpigmentation is not a cause for concern. But the following warning signs suggest that there is an underlying health reason that causes the hyperpigmentation:

  • The spots are growing larger or smaller monthly or weekly.
  • The spots are itchy and painful.
  • They quickly grow darker over several days.
  • The spots fade or go away after a dog is washed or groomed.
  • They are raised from the skin.
  • They appear after sun exposure.
  • Another pet gets the spots.

Any of those are signs your dog might have secondary hyperpigmentation and are signals that your pet might have another disease. Primary hyperpigmentation is like freckles or beauty marks, and there is not much you can do about the black spots.

Your Dog Might Have Allergies

Some dogs have or develop sensitive reactions to food or environmental conditions like pollen and mold. Environmental allergies are usually seasonal, while food sensitivities, which are often confused with allergies, develop over time.

Seasonal allergies can cause atopic allergic reactions. Along with inflamed red or black spots, your pet will scratch more often. Although the paws and ears are commonly affected, other parts of the body, including the underarms and groins, can exhibit the spots associated with the allergy. 

These spots will disappear once the allergen is gone.

Food allergies and food sensitivity are often confused. A dog with a true allergy will have symptoms such as facial swelling, hives, vomiting, or diarrhea. A dog with food sensitivity might have gastrointestinal signs, itchiness, dry skin, or black or red spots.

By themselves, the black spots are probably not a sign of an allergy unless your dog shows other symptoms.

Fleas and Mites Can Cause Black Spots

Flea saliva can cause allergic reactions, and dogs who are allergic to fleas will scratch themselves frequently, typically at the base of their tails or in the groin area. The constant itching can lead to black or red spots.

Ticks can also be responsible for black spots. If you suspect your pet has fleas or ticks, keep it inside and contact your vet for suggestions, especially if your dog is on other medications. Your vet will be aware of negative interactions with other medications.

Mites that dig into your pet’s skin can also cause dark spots. Afflicted dogs will have black spots on their ears, belly, and chest and itch. One type of Sarcoptic mange is contagious and may be spread by other dogs to yours. 

Scabies is zoonotic, meaning they can be spread to humans.

They Might Have a Thyroid Deficiency

Tender black spots are a sign of a thyroid deficiency (hypothyroidism). The spots may grow or become darker, and a dog with a thyroid deficiency will often lose hair.  

Dogs with a thyroid deficiency will also show signs of thinning fur, a dull coat, and weight gain. In addition, they are less able to tolerate cold. An increase in skin pigment and thicker skin is another sign of the deficiency.

Diagnosing this deficiency is done by testing the blood. Because other diseases can affect the results, they should be performed by a veterinarian. If the tests show your pet has a deficiency, the vet will prescribe medication to replace the missing hormones.  

Once thyroid levels have been brought up to normal, your dog’s fur will regrow, and the black spots will either disappear or be covered by the fur. 

Yeast Infection Can Cause Black Spots

This non-contagious infection, which is produced by bacteria in the skin, is a frequent cause of a skin infection. It generally begins with skin irritation (red rashes) and might progress to black spots.

Other symptoms can include:

  • Skin changes—either oilier and greasier or scaly and flaky.
  • Excessive scratching or rubbing against.
  • Hair loss, eating problems, or weight loss.

Yeast infections are most common around the ear or paws and can be treated with topical creams or veterinarian prescribed oral drugs.

There Might Be Internal Bleeding

The blood vessels in your dog’s abdomen might burst or be injured owing to direct contact with hard surfaces. If internal bleeding like hemorrhaging happened, the blood might be trapped beneath your dog’s skin.  

This blood appears similar to black spots, and your dog will be in pain.

If the black spots cause pain, you should take him to the vet to get them checked. In addition, internal bleeding should be addressed, as it is a serious condition and can lead to death.

Bottom Line

If your dog behaves, eats, drinks, and has normal bowel movements, you shouldn’t be overly worried about the black spots. However, if your pet exhibits other behavior that indicates something is wrong, then a call or visit to the vet is necessary.

Dogs won’t hesitate to let you know something is wrong. Excessive scratching, whining, mood changes are your pet’s way of telling you something is wrong. So don’t ignore the signs.

And as always, Live, Love, Laugh, and Scratch our bellies often!

Love you guys,


P.S. If you’re new to this world, you may want to check out my Ultimate Guide for First Time Dog Parents. It’s a great reference to get you started on this journey.

This article has been reviewed by our Editorial Board and has been approved for publication in accordance with our Editorial Policies.


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