Skin Cancer in Dogs: Symptoms, Diagnosis & Early Detection

You've heard of skin cancer in people, but can dogs get skin cancer? What does skin cancer look like on a dog? Dogs can develop several different types of skin cancer and, like in people, each one can have different signs. Fortunately, most skin growths in dogs are benign, ranging from fatty tumours (lipomas) to sebaceous cysts.

Can Dogs Get Skin Cancer?

Yes. According to the Royal Veterinary College, there are various types of skin cancer that can affect dogs. These include:

• Mast cell tumours. The most common tumours in dogs, mast cell tumours affect a type of white blood cell called a mast cell, which can cause cancerous growths on or under the skin. 
• Carcinoma. This cancer can affect various different skin cells and is known by the type of cell affected. Examples include basal cell carcinoma and squamous cell carcinoma.
• Melanoma. This cancer affects the pigment cells that determine the colour of your dog’s skin. 
• Lymphoma. This cancer originates in the lymphatic system, and is known as cutaneous lymphoma when affecting the skin.

While there's no clear answer about what causes some dogs to get skin cancer, Blue Cross describes the following risk factors:

• Sun exposure and sunburn. 
• Compulsive licking of a specific area of skin. 
• Genetics and breed.

Blue Cross explains that dogs with light skin, thin coats, or little fur are at the highest risk of skin cancer overall. Some breeds are also more likely to get specific types of cancer than others. For example, beagles, boxers and bulldogs are among the breeds most at risk from mast cell tumours according to the PDSA. 

Likewise, benign growths are more common in some breeds; Labradors are more susceptible to lipomas, while poodles are especially prone to developing cysts. However, cancer can affect any dog breed, and it is possible to mistake some cancerous growths for benign ones. For that reason, it’s important to stay vigilant and discuss any changes in your dog’s skin with your vet.

What Does Skin Cancer Look Like in Dogs?

Can dogs get skin cancer? Yes. So, what does skin cancer look like on a dog? Blue Cross says that skin cancer can take on many different forms, ranging from lumps and bumps to scabs and warts. Marks or growth can also vary in colour. 

For example, most types of skin cancer look like lumps in the skin, and they may or may not have fur. However, malignant melanoma may appear as a black or brown mark, and may be raised, like a mole, or flat. Cutaneous lymphoma, on the other hand, might present as patches of red, flaky skin, appearing similar to ringworm. Both cutaneous lymphoma and malignant melanoma can quickly become fatal and require prompt diagnosis and treatment. 

If you find a lump on your dog, how much should you worry? As a general rule of thumb, any lump on your dog's skin may be cause for concern, especially if it is new or fast-growing. Say you pet your dog in that one favourite spot all the time. One day, you notice a small lump. Later, you notice that it’s grown in size. This could be a sign of trouble. Keep in mind, though, that some cancers can be firm and others can be soft, so the feel of the growth isn't a reliable indicator.