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7 Types of Bumps Often Found On or Inside a Dog’s Mouth [Vet Advice]

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vet looking at a dog's mouth

This article was updated on September 1st, 2023

Lumps and bumps in dogs’ mouths may represent a wide range of ailments. Oftentimes, the owner doesn’t even know their pet has an oral lump and it is discovered by a veterinarian during a routine health check. This is unsurprising, given that most dogs dislike having their mouths examined too closely.

Whether a new bump is detected inside the mouth, on the lips, or around the dog’s muzzle, this is something we need to take a closer look at. In some instances, your vet may advise that a biopsy be taken so the most appropriate treatment plan can be started.

Most frequent bumps and lumps on or inside a dog’s mouth

In this article, we will first review the top causes of bumps and lumps on or around a dog’s mouth – including on the lips and chin.

Bumps frequently found on the chin and around the mouth:

1. Canine acne

If you see red bumps around your dog’s mouth, especially if they are young or middle-aged, you may well be dealing with canine acne. We can see relatively small scabs and pustules, and certain breeds, including the Pug, Bulldog, and Boxer, are most predisposed. The skin is commonly red and may be swollen and itchy. No lesions will be inside the mouth and these dogs often have other skin issues, such as itchy paws and pink skin on their belly and chin.

dog acne and pimples on a pug

The Pug in the above picture has quite severe acne and there is probably a good deal of bacterial overgrowth here.

Many of these pooches will have allergic skin disease and will react to foods and things in their environment, such as grass and dust mites. We can help them by avoiding allergens as well as treating their skin inflammation and infections with a medicated wash, antibiotics, and anti-inflammatory medicine. View more pictures of dog acne with veterinarian information.

2. Papillomas

Papillomas are also called warts and we see them in dogs of all ages. Sometimes they appear inside your dog’s mouth or near the lips. For younger dogs, they are easily spread from direct contact, as these dogs have yet to develop a natural immunity to the papillomavirus. We also see these raised warts in older dogs, whose immune system isn’t working as effectively as it used to.

warts on a dog's lips near the mouth

Bumps around a dog’s mouth that are fleshy and appear like ‘little brains’ are usually warts. This is especially true in a patient less than two years of age. These are very common and of little concern. In my clinic, I see warts at least once a week.

Thankfully, for the vast majority of our canines, no specific treatment is needed. Their warts will naturally get smaller and go away with time. Much less commonly, the warts are stubborn and need to be surgically removed or treated with a recombinant vaccine. View more pictures of warts in dogs.

White bumps on a dog’s mouth could also be skin tags. These are not associated with the Papillomavirus and are something we see more in elderly dogs. See picture below or view our page about skin tags in dogs.

skin tag on dog's lip

Lumps and bumps inside a dog’s mouth

If you notice a growth inside the mouth, perhaps when your dog is yawning or eating, this is something a vet should look into right away. There are a number of possible causes for a lump in your dog’s mouth, so let’s take a closer look at each.

3. Epulis

One of the most common growths we see on a dog’s gums would be an epulis. These are benign (non-cancerous) growths and they are the fourth most common growth found in the canine mouth according to the Veterinary Information Network (VIN).

We tend to see these fleshy pink or red growths in snub-nosed dogs, including Boxers and Frenchies who are middle-aged. Though they start off small, they can grow quite large, even covering teeth.

closeup of epulis, a tumor of the dental mucous membrane in the gum tissue surrounding the dog's teeth
close-up photos of the mouth of a dog with epulis

As well as a visible lump, owners may notice that their dog is drooling more, has bad breath and is leaving drops of blood behind on their toys and chews.

Your vet can biopsy these growths to determine if they are an epulis and, if so, which type. Treatment will generally include surgical removal. Many owners combine this with a dental cleaning treatment at the same time.

4. Papillomas

Papillomas have been discussed above, but they can equally appear inside the dog’s mouth, not just outside it. Some dogs will develop quite a few of these masses and they will be both inside and outside of their mouths.

Oral warts tend to remain small and look like little cauliflowers. Other symptoms are uncommon but some owners might notice bad breath. If the lesions are rubbed against, they can start to bleed for a short while.

Disclaimer: This content is not a substitute for veterinary care. Always consult with your vet for health decisions. Learn more.

5. Oral melanoma

The most common malignant dog mouth lump is a melanoma. Sadly, these tumors tend to act very aggressively. While they may look quite small, it is not uncommon for them to have grown deeply underneath the visible surface at the time of detection. They can cause teeth to move and even fall out and are associated with bad breath, swelling, and oral infections.

As is seen in the image above, these growths will appear quite irregular, may bleed, and usually contain some darker, black pigment.

To diagnose an oral melanoma, your vet will biopsy the growth. They should also perform staging, to see if the cancer has spread. The mass and any locally affected lymph nodes should be removed, and radiotherapy will be an option for some individuals.

WATCH: 3 Important Tips To Care For an Old Dog [VET VIDEO]

6. SCC (squamous cell carcinoma)

An SCC is the next most common malignant growth we see in our canine companions and they will usually appear on the gums and/or tonsils. This is another aggressive cancer type and often leads to ulceration and local bone destruction.

As well as sampling the tissue, your vet should perform some imaging to determine the extent and spread of the cancer. The treatment will usually consist of surgical removal (where possible) and/or chemotherapy and radiotherapy.

7. Dental abscess

In some cases, oral masses can be due to localized dental disease and infections. When bacteria and pus proliferate, a painful abscess can form under the gum. This tends to come on quickly and may be associated with visible swelling of the cheek. In older dogs, dental abscesses are seen quite commonly, especially when they’ve never had a dental. View more pictures of tooth abscesses.

The dog in the photo above has the classical swelling associated with a tooth root abscess and we’d expect to find advanced dental disease and halitosis (bad breath) within the mouth. These dogs can be quite uncomfortable and may refuse food or have trouble eating.

The treatment is surgical removal of the infected tooth, pus drainage, and the provision of antibiotics and anti-inflammatories.

Signs that veterinarian help is needed

A new mouth lump or bump is something we’ve got to take seriously. This is because there is the potential for these growths to be sinister, and the prognosis is better the sooner treatment is started.

Factors that would be of concern when it comes to oral growths include:

  • A lump or bump that is growing and changing rapidly
  • Masses that are firmly attached to the tissue underneath
  • Lumps that ulcerate on the surface and that become infected
  • Any lump associated with other signs, such as trouble eating or bloody drool
  • A lesion inside the mouth that has dark pigment

Veterinarian diagnosis and treatments for lumps and bumps on a dog’s mouth

Diagnosis for mouth lumps and bumps

More straightforward benign lesions like pustules and papillomas can be recognized by experienced vets without any particular tests being performed. However, if the vet has any doubts or the lesions aren’t resolving, the growth should be sampled. This may mean a fine needle aspirate (FNA) or biopsy.

The cells taken from the lesion should be sent to the lab for analysis so we can know which specific type of oral growth we’re dealing with. This affects both the treatment and prognosis.

When a mouth lesion is found to be malignant (cancerous), your vet may perform staging, whereby they check for signs of spread around the body by sampling local lymph nodes and performing diagnostic imaging studies.

Cost of diagnosis

If your vet is able to determine that you are dealing with a non-sinister lesion in your dog’s mouth, the cost will simply be for the consultation, about $60-100. They will advise you to keep a close eye on things, to ensure the lesions resolve.

If sampling is needed, there will be both lab fees and procedure fees. This will usually be about $150-200 for a FNA or $250-400 for a biopsy, in addition to the exam fee.

If staging is needed, the cost will be much higher as this can involve CT scans and lymph node aspirates. We could be looking at a bill over $2,000 here.


Treatment will depend on what we are dealing with. For pustules and infections, washes and antibiotics are the treatment of choice. For something like a wart (papilloma), most dogs don’t need specific therapy.

When a dog has oral cancer, we want treatment to start promptly. This will include surgical removal of the mouth mass, and possible also chemotherapy and/or radiotherapy. Oftentimes, a specialist oncologist and/or surgeon will need to be involved and the bill can reach several thousand dollars.

Learn more about bumps and lumps on your dog’s mouth, tongue and lips:

Bumps and lumps on dog’s lips

White spots or bumps on dog’s lips

White spots on dog’s tongue

Learn more about common issues with the mouth:

Mouth sores in dogs

Mouth cancer & life expectancy


  • Dr. Linda Simon, Veterinarian

    Dr Linda Simon (MVB MRCVS) has 10 years of experience as a veterinarian. She is a veterinary surgeon with a special interest in geriatric patient care, dermatology and endocrinology. She is a member of the British Royal College of Veterinary Surgeons. She graduated top of her class from UCD School of Veterinary Medicine in Dublin in 2013. Linda has also worked as a locum vet in a range of clinics, including 24 hour emergency clinics and busy charity clinics.

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