Lumps On Dogs. How To Know When To Worry And What To Expect At The Vet

February 7, 2022
a bulldog being examined at the clinic.

When you pay enough attention to your dog, as we know many dog parents do, there are times when you’ll find that something is out of place. Either they’re limping in a way that you don’t know what caused it, or maybe they aren’t as interested in their toys the way they used to be. Changes like those aren’t always something that causes instant concern, but when you notice a lump or bump on your dog’s body that wasn’t there before, panic may come soon after.

While keeping your pet healthy and safe does sometimes require that knee-jerk reaction of fear, a lump or bump on your dog’s skin doesn’t always require a trip to an emergency vet. Below, we’ve broken down some of the different types of lumps that can be found on dogs. Of course, the only one who can tell you that for sure whether a mysterious bump is a cause for worry will be your vet, so be sure to schedule the next appointment available so your furry friend can get checked out.

What is a lump on your dog? How to identify something that shouldn’t be there

For many pet owners, their dog is one of their best friends, if not the best. They spend a lot of quality time with their pet and possibly even their personal space. But even if you are spending every waking minute with your dog, there’s a chance that something new may develop that you don’t notice right away. 

Lumps and bumps on your dog can easily be something you don’t notice for a while. Either they are small enough that you don’t feel it as it develops, or it’s in a spot on their body that you don’t often come into contact with, like the inside of their leg for example.

Finding the lump is the first step. The second will be to not panic, not all bumps on a dog mean that they have cancer. That being said, your next step is to get an appointment with your vet to get the lump checked out and confirm whether it’s something that needs to be worried about or not. 

It’s also often recommended that you measure the bump; knowing where it started with an objective number makes it easier to keep track of the progress of the bump. There are times when our memories and eyes can deceive us into thinking that the bump is getting larger or smaller, and having a measurement will make it easier to know what changes have—or have not—been happening. 

Common types of lumps on dogs 

Lipomas or fatty tumors

Lipomas are commonly thought of as a part of the aging process for dogs. They are benign tumors that are just a mass of fat cells under normal skin. These are usually soft, round, and movable. They are commonly found around the ribs—though they can show up in other places on the body as well—on middle-aged to senior dogs who lean toward being overweight. 

Lipomas are often not something that you need to worry about on your dog. They are slow-growing and shouldn’t cause your dog any discomfort. Your vet will ask you to monitor the growth and if it affects your dog’s day-to-day life. If it grows quickly, or to a point your dog starts to have to work around it, it can be removed. Or it can be removed when it’s diagnosed, as well.1-9

Sebaceous cysts

The easiest way to describe this is that it’s like a pimple on your dog. A sebaceous cyst is a blocked oil gland on your dog. They can be small or grow significantly larger than you’d expect a pimple to. 

Do not try to pop a cyst on your dog. More often than not a sebaceous cyst will go away on its own either by shrinking away or popping in its own time and releasing a white, pasty substance. If you attempt to pop a cyst on your own there is a higher chance for it to become irritated or infected, and it can become a significantly higher threat to your dog’s health in the long run. It’s best to monitor a sebaceous cyst, and if it grows rapidly without popping check in with your vet. But do not try to pop it on your own.1-7,9 


An abscess is swelling caused by puss building up under the skin. This can be caused by anything from an infection to an insect bite. Abscesses can develop quickly and become painful to your dog if not cared for quickly. 

They will always require treatment by a vet to drain the puss safely and prescribe antibiotics to make sure that it doesn’t return or spread infection in their body. While they do require a trip to the vet, they are not typically something that should cause great worry. Most often, they are taken care of and forgotten about once the antibiotics have run their course.2-9


A hematoma is a raised bruise on the surface of your dog’s skin. It can be painful when touched for your dog and comes from a direct trauma to that part of their body. While a hematoma isn’t necessarily something you’d need to worry about for your dog’s health, there is a chance that it is signifying more damage underneath that part of their skin, and should be checked out by a vet to make sure that there aren’t any hidden injuries, like a broken bone, beneath the bump.3,4 


Warts are small bumps on a dog’s skin that have a texture similar to that of cauliflower. They can be caused by many different factors, anything from viral infections, vaccination locations, and even just aging. 

For most younger dogs, their body is developing their immune system and it will be able to heal the wart by itself. However, for older dogs, they may need to be removed by your vet. Either way, if you notice that your dog has developed a wart, it wouldn’t hurt to give your vet a call to see what they think should be done or how to efficiently track its progression.2,4,5,6 


Papules are small bumps that develop, usually around a hair follicle, due to an allergic reaction or are the result of a minor infection. Typically, they will go away on their own after the allergen is removed. However, if you aren’t sure that the bumps are papules, take your dog to the vet to get them checked out; they may also provide an allergy test to help identify what allergen caused the bumps to show up.4

Histiocytoma or Button Tumors

These are red, bubble shaped, non-cancerous tumors that appear on young dogs and puppies any time between ages 8-weeks to 3-years old. They are a buildup of excess immune cells that press into the skin. Normally button tumors are able to go away on their own, but if your pup starts to get irritated by it or bite and scratch it, it may be better to discuss a surgical removal with your vet.5,7,8,9 

Mast cell tumors (cancerous lumps)

Mast cell tumors are the most common form of skin cancer in dogs. They can have many different looks depending on where, how, and when they develop on your dog. They can be both over the dog’s skin—where you would be able to see it past their fur—or under, hidden by their fur. They usually feel solid and firm to the touch and can be irregularly shaped, rather than the expected rounded bump. 

Because mast cell tumors are a skin cancer, they need professional treatment. Your vet will likely recommend a surgical removal of the affected tissue as well as a small border layer around it to make sure that all of the cancerous cells are removed. When caught early, this process is very effective and your pup will be back on the move in no time.1-9

Enlarged lymph nodes

Lymph nodes can be found in many different areas of your dog’s body. Swelling in lymph nodes can be an initial indicator that there may be an infection or something that your dog’s immune system is fighting off. 

Enlarged lymph nodes can be a sign of many different health troubles in your dog, so like all of the other lumps and bumps you may find on your dog it’s important to have it checked out by your vet. 

Common places to find an enlarged lymph node include lumps on your dog’s neck under their jaw or a lump in their armpit. 

Enlarged lymph nodes can mean anything from your dog fighting a small infection to canine lymphoma developing in that area. In either case, noticing that there is a lymph node that is swelling, getting them to the vet as soon as possible to have tests run will greatly improve their chances for easy treatment.

What to expect your vet to do in response to the lump

When you take your dog to a vet to check out a lump that you’ve just found, if it isn’t one of the more unique and identifiable bumps, like a wart for example, they will use different tests to identify what is causing the bump and how much you need to worry about it.

One of those tests will most often be a Fine Needle Aspiration (FNA). This is when your vet will take a small, unintrusive needle and stick the bump to get a sample of cells. They’ll look at the sample of cells under a microscope and use the information that they find there to identify if there are any cancerous properties in the lump and if not, what kind of lump it may be. A majority of lumps on dogs are diagnosed with an FNA.9

If the FNA is unable to identify what is causing the lump, your vet may sedate your dog to take a biopsy of the lump. A biopsy will require a part of the lump, or all of it if it’s small, to be removed and examined closely by a laboratory.8,9 

If the lump has fluid inside, whether the fluid is the main cause of the lump or not, then an FNA cannot be done. In these instances, the fluid itself is extracted and sent to a lab for closer inspection on a molecular level to determine what that fluid is.8,9

Once your vet has the results of any of these common tests, they will come up with the best plan of action. For some cases, the plan will just be to keep an eye on the size and note if it starts getting smaller or larger; if the latter occurs then typically a secondary visit to the vet is necessary. For more serious cases they may recommend antibiotics or surgical removal. 

While lumps don’t always have to cause panic, it’s always better to be safe than sorry. Even if you feel confident that your dog’s bump is the kind that will go away on its own, it doesn’t hurt to give your vet a call. Many vet clinics also list an associate email address, and pet owners are encouraged to use this email address to ask questions and send in photos of their pet's issue. If a lump is something to be concerned about, the clinic will then let you know to schedule a physical appointment.

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