Cat With Swollen Lower Lip (6 Possible Reasons)

My cats lip is swollen

Have you ever woken up one day and noticed that your cat looks kinda pouty almost to the extent of doing a ‘Mick Jagger’?

Or some cat owners might even be surprised that their cats have lips to begin with. And at times it is possible for your cat to look like it has a swollen lip, especially on its lower lip. But what exactly is causing your cat’s swollen lip?

Your cat’s swollen lip can be caused by a wide range of health problems. This can range from something as mundane as an allergy, kitty acne, dental problems or even something as serious as a tumor. There are times when the swelling will subside on its own but most times, your cat’s lips would require medical treatment.

In this article, we will be taking a closer look at each possible reason that could be making your cat’s lip swollen and what you should be doing about it.

My Cat Has Lips?

Take a good look at your cat’s mouth and you’ll be hard-pressed to see your cat’s lips with all that fur covering the skin. Furthermore, your cat’s mouth isn’t open all the time like a dog’s which makes it easier to see the lips.

But your cat’s lips are definitely there.

Cats are mammals like humans which means that they have and need lips for latching on and sucking on their mother’s nipples for milk as kittens.

The best way to take a look at your cat’s lips is to gently lift up your cat’s mouth and you should see a thin black line that runs around its mouth.

That’s the lip.

Why Does My Cat Have A Sore On Its Lower Lip?

My cats lip is swollen

For most cat owners, when your cat’s lip is swollen, it will look like it has a sore on its lower lip. Just like how it would be when we have a cold sore on our lips.

It will be looking red, inflamed, swollen and might even be bleeding.

Here are some possible reasons that could be causing your cat’s lip to be swollen.

1. Allergies

My cats lip is swollen

Cats, like humans, can have their own allergies too. And there are many things that your cat can be allergic to.

The swollen cat’s lips could be an allergic reaction to something that it has eaten or come into close contact with.

Besides having a swollen lip, your cat can also exhibit other symptoms like:

  • Watery eyes
  • Nasal discharge
  • Excessive scratching
  • Red and inflamed skin on cat’s body

The thing with allergies is that they can be difficult to nail down. It is through a process of elimination that most cat owners have to go through to find the root cause.

Sometimes it could be something as straightforward as a type of meat or even dairy. Cats are lactose intolerant and should not be drinking milk.

Sometimes, it could also be due to one ingredient in their canned food that is causing the flare-up.

What Should I Do?

If you recently started feeding your cat a new cat food or added something new to your cat’s diet, revert back to the old and see if that helps with the lip swelling.

If that doesn’t help, it would be best to take your cat to the vet for an allergy test to see what is triggering an allergic reaction in your cat.

Your vet might even prescribe medication like antihistamines to help with your cat’s swollen lip and other symptoms when it happens.

2. Feline Acne

My cats lip is swollen

We associate acne with teenagers and young adults and lo and behold, our cats can get acne too and it is usually found on your cat’s chin.

Feline acne is caused when your cat’s hair follicles get infected with bacteria.

Also known as chin acne, this condition is very common in cats and can be easily spotted by observing your cat’s chin for ‘blackheads’. Your cat’s chin will also look rather dirty like it was rubbed on a dirty surface.

In more serious causes, it can lead to lesions, swelling and itchiness. Your cat will be scratching its chin a lot which might make it bleed.

In some instances, the chin acne in your cat can also cause your cat’s lip to swell up.

There are some causes for this:

  • Allergies
  • Type of food or water dish
  • Food stuck on the chin

What Should I Do?

I’ve always struggled to get rid of my cat’s chin acne in his younger days. It didn’t really start to improve until I did the following:

Used Only Stainless Steel Bowls

There are many cats that seem to have a bad reaction to ceramic and plastic bowls. These materials are known to cause chin acne in cats and they tend to harbor bacteria more easily.

Once I changed out my cat’s bowls to stainless steel, his chin acne got a lot better.

Wipe Your Cat’s Mouth

Our cats do a pretty good job of keeping themselves clean after a meal but not all the time. If your cat is on a raw food diet or wet food, it is quite common for its chins to be wet with food stains after each meal.

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If the cat doesn’t clean that area properly, it can lead to bacterial and fungal infections.

I make it a point to wipe my cat’s mouth and chin with a wet tissue to make sure it’s clean and clear of any food bits.

3. Dental Disease

My cats lip is swollen

Not many cat owners do a very good job of keeping their cat’s mouths clean and I am guilty of that too. But good oral hygiene is very important for your cat’s health.

The common dental issues in cats are:

  • Gingivitis
  • Periodontitis

Gingivitis is a condition that affects your cat’s gums. This can cause the gums to bleed and become inflamed and recede. If left untreated, it can progress to periodontitis whereby the tissues that attach the cat’s tooth to the gums are damaged.

Periodontitis is irreversible as compared to gingivitis. Regardless of whichever it is, we should not even let our cat’s dental health deteriorate to such an extent.

Other symptoms of a dental infection include:

  • Lack of appetite
  • Stomatitis and tooth resorption
  • Drooling
  • Bleeding in mouth
  • Constant pawing at the mouth
  • Constant shaking of the head

What Should I Do?

If your cat is showing any signs of a dental infection or disease, please take it to the vet as soon as possible for treatment.

It is most likely that your cat will have to undergo a dental procedure to remove plaque and whatever gunk that is stuck to its teeth and gums.

Tooth extraction might be required in cases whereby the tooth can no longer be saved.

To do what we can to prevent dental problems in our cats, getting your cat used to having its teeth brushed is a good start.

I understand that trying to brush your cat’s teeth feels like pulling teeth (pun intended) but it is a necessary evil. It is best to start when your cat is just a kitten so that it gets easier as an adult.

Make sure to use only cat-friendly toothpaste as human toothpaste is very toxic to cats.

4. Rodent Ulcer

Rodent Ulcers are ugly look sores that can pop up on your cat’s lip all of a sudden. Many cat owners might think that it is caused by the bite of a rodent but thankfully it isn’t.

It is considered part of a group of skin disorders in cats called Eosinophilic Granuloma Complex.

A rodent ulcer is usually caused by an allergic reaction or flea bites. Cats with autoimmune disorders like FeLV and FIV can also experience the onset of such ulcers.

These sores might seem serious but they don’t cause much discomfort to the cat.

What Should I Do?

Even though the sores might not be causing your cat much discomfort it would still be good to let your vet take a look.

The vet might do a biopsy and run some blood tests to try and determine the cause. These sores won’t heal well on their own and will require a course of antibiotics or topical cream to treat.

5. Stung By A Bug

My cats lip is swollen

Cats are known to be curious about bugs and will not hesitate to investigate or even try to eat them. Unfortunately, not all bugs are safe with some being able to bite and sting.

Here are some common venomous creepy crawlies that you need to keep your cat away from:

  • Scorpions
  • Spiders
  • Bees
  • Roaches
  • Fireflies
  • Caterpillars

Your cat might have gotten too close to one of these bugs and got stung or bitten on the lip.

Other symptoms include:

  • Drooling
  • Seizures
  • Vomiting
  • Diarrhea
  • Difficulty breathing

What Should I Do?

If you suspect that your cat has been bitten by something, get it to the vet immediately Take note of whatever bit or stung your cat and let the vet know.

Time is of the essence especially if venom is involved. The faster your cat is able to get treated the better.

6. Oral Tumors

An oral tumor is a cancerous growth that can happen in any part of your cat’s mouth and lips. This growth can either be malignant or benign.

These tumors can appear as swelling on your cat’s swollen lip and will often break and bleed. It is hard to determine the exact cause for such tumors but it can be genetic or just due to the poor overall health of the cat.

What Should I Do?

Treating oral tumors usually involves surgery to remove the tumor and radiation treatment to kill off any aggressive cancer cells left in your cat.

The best way to give your cat a good chance at fighting this is to treat it early before the cancer spreads to other parts of the cat’s body.

— Update: 11-03-2023 — found an additional article Your Cat Has a Swollen Lip? Here’s Why, & How to Act (Vet Answer) from the website for the keyword my cats lip is swollen.

Cats and dogs have lips just like humans do, although they are usually smaller and less easy to see! Cats also may not let you look at them very closely! Lips are part of what is called a “muco-cutaneous junction.” This means they are the border between normal outside skin and the special skin that coats our mouths, eyelids, and other unmentionable internal structures! These junctions are prone to various issues in all species, and swollen lips can be a common symptom of many problems. Read on for more detail about what can happen to your cat’s lips.

My cats lip is swollen

Why does my cat have a swollen lip?

The fact the lip is swollen implies that something is causing inflammation inside or around the lip. Lots of things can cause inflammation—swelling is a generic immune system reaction that the body has in response to many insults. The swelling itself is usually caused by a surge of white blood cells and fluids into the area, rushing to try and deal with a problem. Let’s have a look at some of the more common things that can cause swellings in lips:

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Cats have a reputation for finesse and elegance, but experience will tell us that they quite regularly end up getting into accidents, scrapes, fights, and knocks. They sometimes do lack common sense! It is not unusual for cats to go headfirst into a trauma and the lips may be damaged through trauma.

Both trauma and any subsequent infection can lead to swollen lips. Typically, the lips would just be swollen in one place, and there may be other wounds around the head, ears, and neck. It is worth checking your cat’s claws—scuffed and damaged claws are a good sign a cat has been through something violent!


A swollen lip over a couple of days that your cat may be licking or cleaning excessively, often seen with wounds or swellings to other parts of the head. The lip will probably look angry and be sore to touch. There may be discharge or pus from the swollen area, and cats may dribble from one side of the mouth. Your cat will otherwise be well and fairly relaxed.

My cats lip is swollen

Stings, Bites, or Reactions

This is usually more of a dog problem, as dogs love sticking their heads into things, but cats may also suffer from reactions to something like a sting, bite, or nettles. If your cat has chased and tried to eat a bee or wasp, for example, a sting to the mouth may cause swollen lips. These are allergic reactions but are usually mild. More severe allergic reactions (known as hives, urticaria, or anaphylaxis) are rare but also possible. Again, the lips will likely be swollen in just one place, though swellings may be found all over.


Sudden appearance (within hours) of a swollen lip—your cat may be holding the mouth open and breathing heavily or harshly. There may be swellings or lumps over the rest of the body. Sometimes the whole head swells up! Your cat will be hypersensitive and agitated, often dribbling heavily from the mouth. There will typically not be any discharge from the swollen area, but you may see a small brown stinger from a bee or wasp—try and brush this out and away with a light touch from a finger if you can do so safely.

My cats lip is swollen

Mouth or Dental Disease

My cats lip is swollen
Image Credit: Ramy kabalan, Pixabay

Cats are prone to diseases of the mouth and teeth. These are known as gingivitis or stomatitis, depending on what parts they affect and how severe they are. Like all animals, cats suffer from tooth decay, tartar, and plaque, but in cats, these can become much more complex and sinister than in other species due to the interactions between several factors in the mouth—bacteria, viruses (especially calicivirus), and the immune system itself.

Where most animals will develop slowly progressive plaque and tartar, cats’ bodies can have massive inappropriate reactions to the bacteria and viruses that live in the mouth and these cause huge amounts of inflammation even if the teeth visually look fairly clean and healthy. This can even cause the teeth to start to be re-absorbed back into the jawbone! As you can imagine, this disease is really painful and unpleasant, just as mouth pain is for us.


Slowly progressive swollen lips (over days to weeks or more) in several places, especially the corners of the lips. The swelling will get gradually worse, alongside other symptoms. Your cat may be slow or reluctant to eat, especially avoiding crunching hard things. You might notice he has bad breath.

If you can see your cat’s teeth, there will be intense redness of the gums around some or all of the teeth, and there may be angry red patches on the tongue and roof of the mouth too. Your cat may groom the mouth and lick, and there may be small amounts of dribble from the mouth. You might notice blood in the water bowl after your cat has had a drink.

My cats lip is swollen

Autoimmune Diseases

My cats lip is swollen
Image Credit: Natata, Shutterstock

Autoimmune diseases in general are rare across all species. In humans, rheumatoid arthritis is a good example of how unpleasant these problems can be. Essentially, the immune system inappropriately attacks or damages some part of its own body.

Cats suffer from a particular group of diseases called “eosinophilic granuloma complex”—known as EGC or as indolent ulcers or rodent ulcers. These are not well understood and can be quite variable, but essentially there is a flood of a type of white blood cells called eosinophils into a particular area of skin. The attack often happens in the mouth, lips, or throat, but can occur anywhere on the cat’s body. This surge of cells causes pain, swelling, intense inflammation, discharge, and oddly can become infected too! They come in three main types but can look very different between cats.

EGC often has no clear cause but has been linked to various things that can trigger the immune system, including food intolerances, allergies to parasites such as fleas or mosquito bites, or something from the environment (pollens for example), and viruses (especially feline immunodeficiency virus – FIV).


Swellings of the skin or mouth appear quite quickly (within days) and can be very itchy and sore. Ulcers affect the upper lip and roof of the mouth—they are raised, red, angry, and quite well defined around the edges. Other types of EGC present as raised, angry areas of skin that are yellow/pink, painful, and weeping with discharge. Cats are usually otherwise well but are uncomfortable and may show difficulty eating. They may be grooming excessively and dribbling.

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My cats lip is swollen

Everything Else

This list is by no means exhaustive and there are many reasons cats can get a swollen lip. Regardless of the cause, if you are concerned about your cat then you should seek professional, expert help from a veterinarian as soon as practical. Only a veterinarian can appropriately diagnose and treat these problems to ensure the fastest proper resolution for your cat.

My cats lip is swollen

What should I do if my cat has a swollen lip?

It is best to seek advice from your local veterinarian if your cat has a swollen lip. As above, there are many reasons cats can get swollen lips and they can be very painful and very difficult to manage. For the most accurate diagnosis and most appropriate treatment, your cat needs professional help as soon as practical. Any delay will cause extended unnecessary pain and discomfort. The biggest challenge is that all of these causes of swollen lips can look very similar, but all need different treatment—so an expert evaluation is needed to tell them apart and provide the proper care at the right time.

Home remedies are not appropriate, given the challenges in diagnosing and treating these problems. Diagnosis is not straightforward and treatments are specific and may be quite intensive, depending on the cause of the problem. There are many home remedies available but these are mostly either not of any use or can be actively harmful to your cat, so they are not advised. At best, they will delay your cat’s recovery and so extend pain unnecessarily. The best and fastest treatments come after a proper diagnosis from a professional veterinarian.

The only home remedy that could be reasonably performed in some cases is giving your cat time—if you suspect your cat has had a trauma but is otherwise well and has a small lip swelling from a cut or knock, then allowing this to heal is not unreasonable. However, if your cat appears in pain or unwell, then again it is best to seek professional help at an early stage. If the swollen lip does not go away within a few days, then again it is best to seek advice—the situation may be more complicated than you think.

My cats lip is swollen

How do you treat a cat with a swollen lip?

This depends heavily on the cause of the problem.

Cats with trauma or reactions to bites and stings usually need an anti-inflammatory to reduce the swelling and the pain. Where the area is infected, antibiotics may be useful but are not required in all cases. Typically, cats will make a full and speedy recovery from these issues.

Dental disease

My cats lip is swollen
Image Credit: Ermolaev Alexander, Shutterstock

Dental disease can be more challenging to deal with and can affect cats of any age. Minor cases may respond well to anti-inflammatory treatment alongside antibiotic therapy. More severe or chronic problems are usually approached initially by an assessment of the mouth under an anaesthetic. This allows your veterinarian to fully assess all the mouth and teeth, take dental X-rays if needed, and give the teeth a really good clean to reduce the bacteria, plaque, and tartar in the mouth as much as possible. It may be better if severely affected teeth are extracted at the same time as they will be causing intense pain.

Where appropriate, swabs may be taken to check for viruses in the mouth (such as calicivirus). Good mouth hygiene is vital in these cases, so your veterinarian may recommend dental care and treatment at home. Some cases may need long-term anti-inflammatory therapy. In the most extreme cases, the problem is only manageable by removing all teeth and so removing all surfaces where bacteria, plaque, and tartar can accumulate.

Rodent ulcers

Eosinophilic granuloma complex (EGC, rodent ulcers) can again be challenging to manage. In most cases, a biopsy will be recommended to confirm the diagnosis and ensure treatment is appropriate. Your veterinarian will perform a thorough examination and talk with you to try and establish any triggering factors. If triggers are obvious, then it may be possible to avoid these in future (through strict parasite treatment, for example).

Some cats benefit from a change of diet if food intolerance is suspected—your veterinarian may recommend a 6-to-8-week trial of a special hypoallergenic or hydrolyzed food, which, as long as it is the only thing your cat eats during the trial, can help diagnose intolerances. The best bit is that if it works, then you already have the long-term treatment for your cat too!

Most cats with EGC require anti-inflammatory treatment that suppresses all those eosinophils, and the most common way to do this is with steroid therapy (usually with prednisolone or dexamethasone). These are safe, cheap, and widely available, with minimal side effects (though they will make your cat eat more, pee more, and drink more). Steroids may be needed just in the short term (especially if there is an obvious trigger to deal with), or sometimes over the long term, seasonally, or even over your cat’s lifetime (if there is no obvious trigger). If the EGC area is infected, short-term antibiotics may also be helpful.

My cats lip is swollen


While not one of the more common cat problems, cats can develop a swollen lip for a variety of reasons. This can be a mild problem with an obvious cause or can be more long-term and problematic. In all cases it can cause real pain and discomfort for your cat. If you are unsure, it is best to seek expert, professional advice from your local veterinarian as soon as practical. Many different diagnoses can all look very similar, but all require very different treatments. For the fastest and most appropriate resolution, get in touch with your veterinary clinic.

My cats lip is swollen

Featured Image Credit: Sharomka, Shutterstock


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