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

Hard Lump on Cat’s Lower Jaw: Causes & Care

If a cat pet parent were to find a lump on their cat’s lower jaw, they are likely to be very concerned. While...

How Long Do Savannah Cats Live? Average Lifespan, Data & Care

Savannah cats are beautiful hybrid spotted cats with long legs and distinctive, large ears. The hind legs are usually just a bit longer...

How Much Are Kitten Shots at PetSmart? Typical Cost & FAQ

Cats require vaccinations throughout their lives, but the most important ones are given when they’re kittens. This is a critical time in which...

Referrals & Second Opinions For Your Cat: Everything to Know

Hi, I’m Dr. Lauren! Read my introduction to learn more about me and my two adventurous cats, Pancake and Tiller. Have you ever...

More related

IMHA in Cats: Signs, Causes & Care (Vet-Reviewed)

IMHA, or immune-mediated hemolytic anemia, describes a condition where the immune system misfires and breaks down the body’s red blood cells, a process...

Can Cats Get Strep Throat? Vet-Reviewed Signs, Treatment & Prevention

Cats, like all living things, are vulnerable to various diseases, including bacterial infections. But can cats get strep throat? Cats can contract different...

Bird Watching for Cats: Environmental Enrichment for Indoor Cats (Vet-Reviewed)

Felines are predators, and although your indoor kitty might not be doing much hunting these days, predators like to locate and catch prey,...

11 Snowshoe Cat Facts: Vet Reviewed Insights on Origin, Appearance & Traits

Snowshoe cats are a striking and relatively new breed that combines some of the best features from two or three different breeds. Snowshoes...

Keep reading

10 Best Dry Cat Foods in Canada in 2026 – Reviews & Top Picks

If you have a new cat and are looking for the best dry food or you need to switch your current cat’s food, you know that there are so many products out there! If you live in Canada, you also...

persian cat eating dry food

10 Best Tasting Cat Foods for Picky Cats in 2026 – Reviews & Top Picks

It’s no secret that our cats love dinnertime. It’s arguably their favorite part of the day! But some cats are a little on the harder-to-please side. Maybe they are spoiled by wet cat food, or they just don’t like the...

tabby cat eating from metal bowl

Fromm Cat Food Review of 2026: Recalls, Pros & Cons

Review Summary Fromm is a family-run business based in Wisconsin. The business started, in 1909, producing the first distemper vaccine for dogs, and sold their first dog food in 1949. Today, the fifth-generation family business produces nutritional, high-quality foods for...

Fromm Cat Food Review

When Do Male Cats Become Sexually Active? Vet-Reviewed Signs & Recommendations

Kittens are cute, fluffy, and fun, but they grow up fast. Not only in terms of size and demonstrating more adult behavior traits, but also in mating habits. Sexual maturity and mating desires start early in the feline community. The...

male cat lying down

10 Essential Cat Grooming Supplies To Get You Started

So, you’re considering getting a new cat? Congratulations! If this is your first cat, you might wonder which supplies your new kitty will need once you bring them home. For example, what do you need to keep your cat clean...

Norwegian Forest Cat Being Groomed While on Human

Why Does My Cat Need Mental Stimulation? 7 Vet-Approved Reasons

Cats are quite curious and inquisitive by nature, so they require a significant amount of mental stimulation to satiate their curiosity and keep them happy. Along with keeping them engaged, mental stimulation can also boost a cat’s mood, increase their...

two cats playing with toy at home

Ragdoll Cat Health Problems: 20 Vet-Reviewed Issues

As one of the most popular cat breeds, Ragdolls are known for their docile and placid temperament. Their trademark move is to go limp in your arms when you hold them, hence the name “ragdoll.” They’re typically healthy and free...

Catster_Health Problems of Ragdoll

Is Schefflera Toxic to Cats? Vet-Verified Facts & Safety Guide

Schefflera are popular subtropical plants that are commonly grown indoors. These pretty houseplants feature oval leaves that appear to drop from a central stem. Some people think the leaf configuration resembles an umbrella. Hence this beautiful houseplant’s most common other...

Catster_Is Schefflera Toxic to Cats

Love Cats? So Do We! Join the Catster Community

Stay informed with expert pet care insights delivered straight to your inbox! Discover professional guidance on animal behavior, feeding tips, trusted product picks, and much more.




Sign up for the Catster Email Newsletter

Stay informed with expert pet care insights delivered straight to your inbox! Discover professional guidance on animal behavior, feeding tips, trusted product picks, and much more.