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Why are there brown spots on my dog’s stomach?

If there are brown spots on your dog’s stomach, this post will show you likely reasons why and what you can do about it.

Why are there brown spots on my dog’s stomach?

Brown spots on a dog’s stomach (hyperpigmentation) are a sign or symptom of an illness, not a disease, and they can have any one of a number of causes. There are two types of hyperpigmentation. The first is called primary hyperpigmentation, and the other is called secondary hyperpigmentation.

Primary Hyperpigmentation

Primary hyperpigmentation usually manifests by the time a puppy is one year old. This type of hyperpigmentation is quite rare, and it is thought to be breed-specific. Dachshunds are typically the only breed that suffers from primary hyperpigmentation. 

Secondary Hyperpigmentation

Secondary hyperpigmentation occurs among every breed of dog, and it’s actually quite common. Symptoms and conditions that may accompany the brown spots are hormonal abnormalities, skin infections, contact dermatitis (common among German Shepherds, Irish Setters, Golden Retrievers, Border Collies, Dalmatians, Labradors, Dobermans, and Great Danes), allergies (common among Lhasa Apsos, Yorkshire Terriers, Irish Setters, Jack Russell Terriers, Basset Hounds, German Shepherds, and Labrador Retrievers), and obesity (common among Pugs, Beagles, Dachshunds, Cocker Spaniels, Cairn Terriers, English Bulldogs, Labrador Retrievers, and Rottweilers).

Besides brown (sometimes bordering on black) spots and thickening of the belly skin, you may also notice that the skin in the affected area becomes rough or conversely, velvety. There may also be hair loss in the area. Other areas, besides the belly, that may be affected are the armpits, legs, and groin. The brown spots may start to look red at the edges. If you notice this redness, your dog probably has a yeast or bacterial infection that’s secondary to the hyperpigmentation. Be aware that infections of this kind can easily spread.

Is it normal for a dog to have brown spots on their stomach?

Hyperpigmentation, while not unusual, is not normal either. That is to say that brown spots on a dog’s belly don’t just show up in a dog who is completely healthy, and they are often accompanied by a thickening of the skin of the belly. To reiterate, there are a number of possible primary causes for hyperpigmentation. Among them are hypothyroidism, allergies, systemic Lupus erythematosus, Malassezia, pseudo Cushing’s syndrome, and demodicosis.

One-third of dogs with hypothyroidism get hyperpigmentation. Malassezia is a type of yeast infection with which hyperpigmentation often presents, and dogs with allergies may show signs of hyperpigmentation, as well. These are the more common causes.

What to do if my dog has brown spots on their stomach?

You have noticed that your dog has brown spots on their belly, but you are unsure what you should do. Here’s what to do if your dog presents with hyperpigmentation.

If you notice that your dog has hyperpigmentation, you should call their veterinarian and make the soonest appointment they have available for an examination. The vet will do a physical exam of the body, paying close attention to the affected area. They will probably take some samples of the darkened areas of skin by scraping the skin carefully and gently. The vet can use these samples to test for infections and parasites. If they think a food allergy is responsible, they may suggest using some type of methodical food trials to detect the culprit.

If none of these is the answer, your vet may want to do further testing to determine the underlying cause. For primary hyperpigmentation, there is no cure, but if you catch it early, it can often be well-managed. For secondary hyperpigmentation, your dog’s skin will heal and return to normal once the cause is dealt with.