Brown Spots on a Dog’s Skin: What Are They?

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Treating Brown Spots On a Dog's SkinHealth issues in dogs aren’t always easily spotted and this is especially true when it comes to the skin of dogs. Pet parents will often think of scaly skin as nothing more than a cosmetic issue and it may seem like it to the naked eye. However, this article takes a closer look into the various skin issues usually encountered by owners, including brown spots on a dog’s skin and how they can be treated. 

What are Brown Spots on a Dog’s Skin? 

If you’ve recently noticed dark spots on your dog’s belly, you’re probably wondering what they are. Below are possible causes of brown spots in dogs and what you can do about them. 

Bacterial and Fungal Infection

Fungal or secondary bacterial infections are skin conditions in dogs that can cause the affected area to become inflamed and irritated. One of the most common signs of these infections is brown spots on your dog’s skin, along with red, scaly, and itchy skin. As soon as you see these symptoms in your dog, be sure to take it to your vet for the appropriate treatment. 

This could include antifungal or antibiotic medications and in some cases, may involve additional treatment such as topical creams or medicated baths. When given the right solutions, most dogs will be able to recover from these kinds of infections without a problem. But if dogs are left untreated, they may suffer from serious health issues.  


These are tiny brown insects that feed on animal blood to survive and are commonly found in dogs, causing them skin problems and irritation. While they can be hard to look for in your dog’s fur, you may notice signs of an infestation through bald spots or excessive licking. If you suspect that your dog might have fleas, carefully inspect their skin; you may find small black specks known as flea dirt.  

Locating them is important because not only are they a nuisance but they also carry diseases and may cause anemia. Most flea bites will only cause itching but some may cause an allergic reaction that could lead to skin diseases, hot spots, and hair loss. To eliminate fleas from your dog, give them a bath using flea shampoo and use a comb to remove the insects from their fur.  


As your dog ages, it can get thinning and dry skin that causes brown spots or dark patches to appear known as age spots. If you see these on your dog, be sure to contact your vet to ensure that the darkening of the skin isn’t caused by an underlying condition. There are many ways for you to treat these kinds of spots on your dog’s skin including lightening creams or ointments, laser therapy, and home remedies such as lemon juice or vinegar.      

But no matter which option sounds the best for you, be sure to talk to your veterinarian to get their advice on the best route to take. 

Allergic Reaction

An allergic reaction can cause all kinds of problems on dog skin which include the appearance of brown spots. Allergic reactions will often result in skin redness and itching but can also result in secondary infections such as a bacterial infection or yeast infection (also known as Malassezia dermatitis). There are various kinds of allergies that may take place in your dog’s body, such as skin allergies or food allergies

The latter is one of the most common problems in dogs, so be sure to do food trials first before switching your dog over to a new food; this will ensure that your dog has no allergies to it. Dogs can also be allergic to environmental factors such as dust mites, mold spores, and pollen. If you see that your dog is in discomfort or has been scratching excessively, be sure to take it to your vet to have them determine the cause of the problem and get the right treatment.  

Diagnosing and Treating Brown Spots 

When you want to check the brown spots found on your dog’s belly, your veterinarian will follow a process to ensure an accurate diagnosis of your dog’s medical condition. Below is a general breakdown of what you can expect. 

  1. Physical Examination: The first thing your vet should do is perform a thorough physical exam on your dog. They should inspect the brown spots and check for other signs or symptoms of illness. 
  2. Medical History: Your vet might ask about your dog’s diet, activities, environmental changes, and medical history to see where the brown spots may have come from.  
  3. Diagnostic Tests: The vet could suggest doing diagnostic tests depending on your dog’s initial assessment, such as blood tests, bacterial or fungal cultures, skin scrapings, and even allergy testing to help identify an underlying issue. 
  4. Treatment: When your vet has determined the cause of the color change on the dog’s skin, they will recommend the right treatment plan which may include the following: 
  • Topical creams or ointments such as steroid ointments for allergies or infections
  • Medicated shampoo for chronic inflammation or skin irritation 
  • Dietary supplements or changes if the condition is related to allergies or nutrition
  • Control measures for parasites such as ticks, fleas, and mites
  • Sometimes, other kinds of therapies or treatments might be necessary if the spots are caused by an underlying disease 
  1. After Care: Your vet may also schedule follow-up visits to check on your dog’s progress or adjust their treatment if needed. They can also give you further guidance on how to prevent these spots from recurring in the future or at least minimize them. 

Are New Brown Spots a Sign of Cancer? 

While they do have the potential to be cancerous, it’s imperative to remember that not all spots will turn out to be cancer. Some kinds of skin cancer such as mast cell tumors or melanoma can look like pigmented lumps or spots on your dog’s skin. They may change in shape, size, and color as time passes, but they may also bleed or become ulcerated.  

At the sight of brown spots, be sure to visit your veterinarian to quickly determine if they are benign or malignant. 

What Causes of Hyperpigmentation in Dogs? 

Hyperpigmentation refers to the thickening or darkening of your dog’s skin and is usually more visible around the lighter part of your dog or around hairless skin such as the belly or groin area. Take note that hyperpigmentation isn’t a disease itself, but is a reaction to an underlying problem affecting areas of the skin. There are 2 types of hyperpigmentation which are discussed below.  

Primary Hyperpigmentation

There are various primary diseases that can cause hyperpigmentation in dogs and while they can occur in any breed, they are especially common in Dachshunds. This type of hyperpigmentation will typically become visible by the time your dog turns a year old.    

Secondary Hyperpigmentation 

Just like the first kind, secondary hyperpigmentation can occur in all kinds of dog breeds and is caused by inflammation or friction. This can lead to additional skin changes like hair loss, odors, pain, and thickened skin. Secondary Hyperpigmentation is more common and will be the result of underlying causes such as skin infections, hormonal abnormalities, obesity, and skin allergies. 

This condition is also more common in dog breeds prone to hormonal imbalances, such as Labrador Retrievers, Basset Hounds, Pugs, Jack Russell Terriers, and Golden Retrievers, as well as contact dermatitis, commonly seen in Yorkshire Terriers, German Shepherds, Irish Setters, Golden Retrievers, Dobermans, Labrador Retrievers, Border Collies, Dalmatians, and Great Danes. 


Brown spots on a dog’s skin may be a harmless skin condition or it can also be a cause for concern. Such spots could be caused by different factors, including skin infections, allergies, parasites, and even hyperpigmentation. It’s a good idea to visit your vet right away to rule out the possibility of any specific disease and to get the right treatment plan organized according to your pet’s needs.