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Health & Wellness

Types of cysts and bumps on dogs

Know when it's time to see the vet.

Your dog is your best friend — so when you notice they have a new lump or bump, it’s natural to feel worried. Don’t jump to conclusions about their health too quickly, though. Fetch’s on-staff vet Dr. Aliya McCullough shares the different types of lumps on dogs and what they mean.

What causes lumps and bumps on dogs’ skin? 

Always check in with your doctor if you find a lump on your dog. Some common causes of lumps and bumps on dogs are: 

  • Inflammation or swelling that’s usually in response to an insect bite or bacteria
  • An abscess, or a painful accumulation of pus caused by bacteria
  • Allergic reactions that look like hives
  • Scar tissue that appears after a reaction to a vaccination
  • Cancerous growths
  • Cyst (aka a formation of fluid or cell debris)
  • Cuterebra or warble flies (bugs that typically burrow into rodents’ skin, but can attach to dogs if they’re exposed)

If the lump is accompanied by signs of sickness, it could mean your dog is experiencing an internal illness, like tumors, swollen lymph nodes or thyroid cancer. Symptoms of an internal illness may include: 

  • Vomiting
  • Diarrhea 
  • Lack of appetite
  • Chronic thirst 
  • Going to the bathroom often

Types of lumps and bumps 

A lump can often be identified by where it develops on your dog — here are some examples: 

  • Histiocytomas are small growths found on dogs’ heads, ears and legs. They’re typically common in younger dogs and usually go away on its own. 
  • Lipomas, aka fatty tumors, commonly form on dogs’ chest, belly or legs.
  • Sebaceous adenoma resemble warts and are found on older dogs’ legs or torso.
  • Papillomas are contagious bumps (similar to warts) that develop around dogs’ mouths and on top of the skin. 

Lumps vs. bumps on dogs

There’s no difference between lumps vs. bumps (including growths and masses). Regardless of how you choose to describe them, growths on dogs should always be tested by a veterinarian. 

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Concerns and treatments

You should always get your pup’s lumps tested to be sure they’re not spreading, limiting your dog’s movement or about to rupture. Your vet will know the best plan of action. Some common tests include:

  • Fine needle aspiration (FNA): A needle will extract a sample of cells from the growth for testing.
  • Biopsy: A portion or the whole lump will be removed and sent to a lab for review. 

How your vet treats a mass depends on if it’s cancerous or noncancerous. Some masses heal on their own, while others need to be surgically removed or undergo chemotherapy or radiation. Make sure your pup is signed up for Fetch Dog Insurance, which can help alleviate additional stress during this time. If your vet needs to run tests to diagnose the lump, Fetch pet insurance can help cover the cost.

Monitor changes in your dog’s lumps or bumps 

No matter the lump, it’s always a smart move to contact your vet. Sometimes lumps can appear on dogs overnight — if they don’t seem to bother your pet, you can monitor the growth at home until your next vet visit. But, if your dog starts licking or scratching the bump, or it changes in appearance, contact your vet as soon as possible. If the lump has been around for a while and doesn’t seem to bother your dog or change, keep an eye on the growth and check in with your vet at the next appointment.

If the growth does start to change, there are some key differences you should watch out for:

  • Black or purple coloring
  • Open sores
  • Pink spots or bruising around the lump
  • Hardening texture 
  • Growth
  • Discomfort

No one takes care of your dog better than you do — these tips just provide some direction on how to handle a lump that’s appeared on your pup.


The Dig, Fetch Pet Insurance's expert-backed editorial, answers all of the questions you forget to ask your vet or are too embarrassed to ask at the dog park. We help make sure you and your best friend have more good days, but we’re there on bad days, too.

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