What is that strange bump on your dog? Discovering a skin lump or bump on your dog can set your mind reeling and your heart racing, but there’s no need to panic. A bump on your dog doesn’t automatically mean something serious, like cancer. While skin bumps and strange lumps on dogs should always be taken seriously, certain types of bumps are more common than you might think, and they’re often harmless.

Types of Skin Lumps and Bumps on Dogs

Skin bumps that you’re likely to find on your dog fall into several categories. Some of these are more common in puppies, some are more common in older dogs. Here are some common bumps:

  • Lipomas: these fatty tumors appear as soft, round lumps of flesh beneath the skin. They’re made up entirely of fat cells and are always benign, or non-cancerous. They’re usually found in older dogs and dogs who are overweight. Larger breeds are more prone to them, although they can be found in small breeds as well. Your vet may perform a fine needle aspirate, using a thin needle to collect cells and examine them under a microscope to verify that they’re fatty tissue.
  • Sebaceous cysts: these are smaller bumps that can look like a pimple or a wart. They form from blocked oil glands and may burst and release a pasty white goo. These most commonly occur in breeds with fine hair, like the Poodle and the Bichon Frise. They may disappear on their own, although some can remain for years and have the potential to become infected. Surgical removal is an option if they irritate your dog.
  • Warts: these small, cauliflower-like bumps are caused by the papillomavirus. They occur most often in puppies who don’t yet have fully-developed immune systems and usually disappear on their own. They typically occur in/around the mouth. This virus is contagious among dogs. So if you suspect your dog has papillomas, it’s important you avoid contact with other dogs until your vet checks it out.
  • Skin tags: these are fibrous bumps that look like small flaps or raised stalks of skin, although they may occasionally look like small bumps. They may or may not have hair growing on them. Skin tags are caused by overactive cells called fibroblasts and can occur in dogs of any breed or age. They’re often harmless, although your vet might want to do a biopsy to make sure, especially if the tag changes in shape, color, or size.
  • Abscesses:  are usually caused by an infection, abscesses are swollen tissue that can form around bug bites, animal bites, infected glands, and other types of sores. If not treated early they may burst, which is painful for your pup. Antibiotics may be required to treat the infection.
  • Button tumors: also known as histiocytoma, are benign tumors that affect puppies and young dogs between eight weeks and three years of age. They’re caused by an overproduction of immune cells and typically disappear on their own. They are typically confirmed under a microscope with a needle aspirate.
  • Mast cell tumors: these are cancerous tumors that may occur either beneath or on top of the skin. They can behave very benignly, or quite aggressively. They’re often solid to the touch and vary in shape. The appearance of such a tumor should receive immediate attention from a veterinarian. Mast cells are easily identified microscopically. Your vet will likely perform a ‘fine needle aspiration’ to collect a sample and evaluate it. If a mast cell tumor is confirmed, surgical removal is recommended. A biopsy of the tumor will determine whether additional treatment is needed.

Pet owners should keep in mind that, with certain types of lumps like lipomas or skin tags, the presence of one or two lumps may increase the likelihood of more lumps developing down the road.

When Should You Worry?

Have your pup examined immediately if you discover a lump that’s hard or firm to the touch or irregularly shaped, or if you notice a change in any existing lumps or bumps regarding size, texture, or color. Your vet should also immediately take a look at any bumps that ooze fluid. But again, while some lumps and bumps are harmless, it’s best to let your vet take a look at any new bumps that appear and let them make that determination.

Lumps are likely to develop at some point in your dog’s life. In cases such as cancer lumps or an abscess, early detection and treatment can improve your dog’s quality of life, and potentially save them from serious and life-threatening consequences.