Get

In Your Inbox

Catster is reader-supported. When you buy via links on our site, we may earn an affiliate commission at no cost to you. Learn more.

Why Are There Sores Around My Cat’s Mouth? (Vet Answer)

veterinarian checks teeth or mouth to a cat

Whether they’re yelling at us for more food, booping our head with theirs, or helpfully cleaning our eyebrows, we often find ourselves in pretty close proximity to our cats’ mouths, so when something is amiss, we usually know. Although it can be more challenging to see what’s going on inside your cat’s mouth, lesions on the outside can be quite worrying.

There are four main causes of sores around the mouth in cats: indolent ulcers, feline acne, infection, and squamous cell carcinoma. We’re going to look at the clinical signs and treatment of each of these in the following article.

divider 3 paws

What Causes Sores Around a Cat’s Mouth?

Most of the diseases that cause sores around a cat’s mouth can appear quite similar. Diagnosing them will usually involve taking a clinical history, looking for other lesions inside the mouth or around the body, or taking samples for cytology.

Sometimes sores around the mouth can be an indication of an underlying disease process, such as feline leukemia, feline immunodeficiency virus, or feline herpesvirus, so a vet may also recommend blood tests.

1. Indolent Ulcers

These lesions are known under a few different names, including eosinophilic granulomas and rodent ulcers. The latter came from an old (and incorrect) belief that these swollen lip lesions were the result of a rat bite. In reality, they are a response to immune stimulation.

Clinical Signs

These ulcers often appear as mildly inflamed swellings on the middle of the lower lip, but they can form anywhere around the mouth. Mild cases will resolve on their own, but most of the time, they require treatment of some sort.

If the indolent ulcer becomes deep and infected, it can be quite painful, resulting in excessive salivation, even making it difficult for the cat to eat. One of the main differentials for indolent ulcers of the mouth is squamous cell carcinoma (which we will discuss later); however, this tends to affect older cats, whereas indolent ulcers are more commonly seen in younger/middle-aged cats.

If your pet is showing these signs, we suggest you speak to a vet.

If you need to speak with a vet but can't get to one, head over to PangoVet. It's an online service where you can talk to a vet online and get the advice you need for your pet — all at an affordable price!

PangoVet_Mention-in-Content for PangoVet2 save money

Treatment

Treating oral indolent ulcers involves a two-pronged approach: treating the ulcer and identifying and treating the immune stimulus.

Treatment of the ulcer usually involves a high dose of steroids, which may need to be repeated once or twice. This settles the effects of the immune reaction and brings the swelling down. If there is an infection present, antibiotics or an antibacterial cleaner may be used.

The most common cause of the immune reaction is fleas, with food hypersensitivity being another potential trigger. Good flea prevention is therefore essential to the management and prevention of this condition. If a food allergy is suspected, an elimination diet using a novel protein or hypoallergenic diet may be recommended.

Sometimes, the immune trigger cannot be identified, and treatment is focused solely on bringing the inflammation under control. In most cases, the prognosis for cats with indolent ulcers of the mouth is quite good, although it is not unusual for the lesions to recur seasonally.


2. Feline Acne

Also known as follicular keratinization, feline acne is a particularly common feline affliction, but fortunately, it is rarely a severe one. The most common sign of feline acne is dark crusts or scabs under the chin, where the skin becomes thickened around the follicles, causing an accumulation of natural skin oils and cells. These lesions can become inflamed and infected and require antibiotic treatment. In most cases, feline acne can be managed with an antibacterial skin cleanser.

The actual cause of feline acne is unknown; however, any conditions that could cause immunosuppression or skin reactions could exacerbate it.

Infection

Infection can occur anywhere in and around the body, including the face and mouth. The conditions already discussed can develop secondary infections, or your cat may have a wound that has become infected. Severe dental disease can even cause inflammation and infection of the lips, so a thorough dental examination is always needed when your cat has sores around the mouth.

Some fungal infections can also affect the mouth, face, and lips, including ringworm and fungal stomatitis.

Treatment will depend on the type and location of the infection and will often involve a combination of oral medications and topical treatments.


3. Squamous Cell Carcinoma

This is the most common form of skin cancer in cats, and it is most often found around the eyes, nose, ears, and mouth. Squamous cell carcinoma (SCC) is a malignant and invasive tumor, with early surgical removal often quite effective. Unfortunately, many cases are quite advanced before a diagnosis is made, particularly when the tumor is located inside the mouth.

SCC can easily be mistaken for an indolent ulcer in the early stages, so cytology is a good idea to rule it out. SCC is more common inside the mouth than around the outside, so we recommend getting your cat comfortable with having their mouth examined, as early detection could save their life.

Veterinarian checks teeth to a big maine coon cat at vet clinic
Image Credit: Ermolaev Alexander, Shutterstock

divider 1 paws

Final Thoughts

There are a number of conditions that may cause sores around your cat’s mouth, all of which warrant a visit to the vet. Although most of these diseases are relatively mild, they can deteriorate rapidly if they become infected. The potential risk of squamous cell carcinoma is another important reason why you should always consult a vet if you notice any lumps, bumps, ulcers, or sores on your cat’s face or the rest of their body.

Become confident when examining your cat’s mouth, and if you are in doubt, do not hesitate to get your cat checked out.

See also:


Featured Image Credit: PRESSLAB, Shutterstock

Want content like this delivered to you?

Sign Up For Our Newsletter

News, insights, expert advice, and everything cat

* By submitting, you agree to our Terms & Conditions and Privacy & Cookies Policy.

How useful was this post?

Click on a star to rate (you can leave written feedback after clicking submit)

Help us improve Catster for pet parents!

Your feedback really matters.

What did you like about this post? Also how can we improve it?

Join the conversation

Leave a Reply

You’re very welcome to leave a comment or question. Please know that all comments must meet our community guidelines, and your email address will NOT be published. Let’s have a positive and constructive conversation.

Talk With A Vet Online

Peace of mind,
anywhere, anytime

Affordable vet advice

We Chat with Andrew Hsieh: Owner of Seattle’s First Cat Cafe

Seattle is fairly well known as being a cat friendly locale. We rank second in the United States for the number of single...

8 Best Cat Foods to Prevent Vomiting in 2026 – Reviews & Top Picks

One of the most frustrating things for a cat owner is when their cat is frequently vomiting. It will often be something simple...

Kitty Horoscope: October Belongs to the Lovely Libra Cat

Astrological signs can tell us a lot about ourselves and how we function in the world. But does it just stop with people?...

Inside the World of Cats Who Own Ice Cream Trucks

While searching Instagram for photos of things like cats destroying jigsaw puzzles, cats paying tribute to David Bowie, and cats who somehow resemble...

More related

200+ Witch Cat Names: Great Ideas for Your Wiccan Cat

Cats have often been tied to mystical practices and have also become common companions for witch figures and characters in pop culture. Therefore,...

Siamese Kittens for Sale in Ohio: Breeders List 2026

Catster advocates for adopting before shopping, though we fully understand there are many reasons for seeking a breeder. So, we encourage it to...

9 Things to Do If You Want to Buy a Purebred Cat: Vet Approved Advice

Catster advocates for adopting before shopping, though we fully understand there are many reasons for seeking a breeder. So, we encourage it to...

Does Lyft Allow Cats? Pet Policy & Travel Tips

There are times in life when you might need to travel with your cat. Whether you are flying on vacation or trying to...

Keep reading

Can Cats Eat Brownies? Vet-Reviewed Facts & FAQ

You might like baking up a big batch of hot, gooey brownies for a treat, but that doesn’t mean that everything that you eat is safe for your cat to consume as well. It is crucial to understand that brownies...

Can Cats Eat Brownies

Can a Cat Overheat? Vet Approved Signs & How to Help Them

Due to their desert-dwelling ancestors, cats are often believed to not be affected by hot weather. While their normal body temperature is higher than our own—101.0°F to 102.5°F—cats are no better at handling overly hot weather than humans are. Cats...

cat stretching a rocky beach and a beautiful sunset over the ocean

Do Cats Feel Sad in the Same Way Humans Do? Vet-Reviewed Feline Behavior

A cat’s brain is very complex, and very similar to a human’s brain in some ways. This enables them to experience a range of different emotions, such as sadness, anger, fear, joy, and surprise. However, cats will not show emotions...

sad looking cat lying on a table

Can Cats Eat Takis? Vet-Reviewed Precautions & Health Guidelines

Did you know that cats only have 473 taste buds1? Humans have about 9,000 taste buds. This means that a cat lacks a lot of flavor sensors, mainly sweet and also spicy. These flavors simply don’t register the same as...

Can Cats Eat Takis

6 Natural Home Remedies to Treat a Cat Wound (With Pictures)

Whether your cat is an indoor or outdoor cat, she is likely to pick up scratches and scrapes at some point in her life. The most common type of injury is that of a scratch or bite from another cat,...

cat with bandage

Why Do Cats Like Chin Scratches? 9 Vet-Reviewed Reasons

If you own a cat, you know that cats love chin scratches. You’ve probably noticed that they will rub their cheeks against your hand or any other surface if you give them the chance. That’s because cats have scent glands...

woman scratching cat's chin

Can Cats Eat Peppermint? Vet-Reviewed Facts & Precautions

Peppermint is a common ingredient in many things, from food to skincare. It’s not unlikely that your cat will come into contact with peppermint at some point in their life, and if the item seems tasty enough, they might give...

Can Cats Eat Peppermint

Can Cats Eat Dog Pill Pockets? Vet-Reviewed Facts & FAQ

Unfortunately, almost all cat owners experience times when their cats are prescribed medication for a health condition. Cats don’t generally enjoy eating things that don’t taste like their favorite things, like fish, chicken, and beef. If you think about trying...

Can Cats Eat Dog Pill Pockets