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5 Explanations For A Cat’s Swollen Lip, And How To Help

5 Explanations For A Cat’s Swollen Lip, And How To Help

Have you suddenly noticed a swollen lip in your kitty? Everything seemed fine last night, and now her lip looks pretty huge, and it’s red! What could have caused this?

A cat’s swollen lip is not that rare. This can happen for less serious, but also quite severe reasons, which can even be life-threatening for your kitty.

It is very useful to learn what can cause this change in the cat’s lips, but also how you should act in each possible situation.

1. Allergies

longhaired cat with allergies licking its swollen lip

Some cats might struggle with an allergic reaction, which is an immune response sensitivity to certain substances in their surroundings.

According to Pet MD, the most common allergy types in felines are food allergy, atopic dermatitis, allergic contact dermatitis, flea allergy dermatitis, and cutaneous drug eruptions.

Some of the allergy symptoms in cats are itchy skin, hair loss, sneezing and watery eyes, gastrointestinal problems, respiratory issues, and skin swelling.

So, if you suddenly noticed a swollen lip in your kitten, she might be having an allergic reaction.

How To Help?

If you suspect an allergic reaction in your cat, you should take her to the vet immediately. He will bring the cat’s allergic reaction under control, and will determine which allergen caused your pet’s problems. 

Most often, skin tests, as well as blood tests, will be needed to identify the allergen.

Therapy will depend on the cause, as well as the extent of the allergy. In general, allergy therapy for cats includes anti-allergic drugs, immunosuppressants, as well as anti-inflammatory shampoos or ampoules.

Most allergic reactions in cats are mild, but there is a possibility that they can lead to anaphylactic shock, which can even be fatal for your kitty.

Therefore, it is very important that you react in time and that your cat receives the appropriate therapy.

2. Injury

Red cat with a swollen upper lip, inflammation on the muzzle of the cat

A cat might also have a swollen lip due to an injury. This can happen for many reasons, such as if somebody steps on your cat, if she gets in a fight with another cat, or if she simply has an accident during her playtime.

Kelly Saverino and Alexander Reiter [1] point out how some cats with injured lips will be unable or unwilling to eat. 

In some cats, the swollen lip will subside in a day or two, while in others the injuries will be more serious, so you will be looking at your pet’s enlarged lips for much longer.

How To Help?

You should apply a warm compress on your cat’s swollen lips for a couple of minutes. 

Furthermore, you should look for any other signs of trauma on your cat’s body. If you notice any blood, or your cat appears to be in a lot of pain, you should consult your veterinarian.

If you decide to clean the area around your cat’s lips on your own, use a mild antiseptic solution. Any harsh chemicals can additionally irritate the swollen lips.

3. Dental Problems

Open adult cat's mouth showing sharp teeth surface

Dental problems can also cause lip swelling in cats. In addition, a cat could also have bad breath, might refuse solid food, bleed from the oral cavity, show weight loss, and mood changes – many cats will hide and even be aggressive.

The most common causes of dental problems in cats are cracked or broken teeth, caries, increased presence of plaque, and worn teeth.

Some of the dental diseases that can occur in cats are gingivitis, periodontitis, and resorptive damage to the teeth.

How To Help?

The treatment will depend on the exact cause of the dental problem in your cat.

For example, in the case of gingivitis, Cornell Feline Health Center explains that some cats will need antibiotics, or immunosuppressive drugs. In some severe cases, it might be necessary to remove the teeth that are a source of inflammation.

Periodontitis treatment refers to removing plaque and mineral buildup, and polishing the cat’s teeth. Of course, the main goal is to save all of your cat’s teeth, but, in some cases, the extraction of teeth will be required. 

Dental problems can be very painful for felines, just like for humans. They can severely impair the cat’s quality of life. 

This is why it’s very important to wash your cat’s teeth regularly, to use cat toothpaste only, and to take your cat for vet checkups at least once a year.

4. Eosinophilic Granuloma Complex (EGC)


Kaitlin Hopke and Sandra Sargent [2] describe the Feline Eosinophilic granuloma complex as a group of reaction patterns that affects the oral cavity, skin, and mucocutaneous junctions of cats.

This complex refers to a group of three skin conditions in felines. The first one, eosinophilic ulcers, presents red skin ulcers that usually appear on the cat’s upper lip.

The second one is eosinophilic plaque, which is most commonly found on the cat’s belly and thighs, causing them to scratch excessively.

The third condition is called eosinophilic granulomas, and these nodules can be found anywhere on the cat’s body, but mostly on her head, face, ears, lips, and chin.

Eosinophilic Granuloma Complex might appear due to genetic factors, insect bites, or dietary, or environmental allergens.

How To Help?

As MSD Veterinary Manual suggests, a cat’s swollen lips due to Eosinophilic Granuloma Complex can usually be treated with antibiotics. 

If the veterinarian cannot identify the exact cause of this condition, he might prescribe a treatment with cyclosporine or corticosteroids.

5. Oral Cavity Tumor

cat orange cat with oral cavity tumor

Unfortunately, a cat’s swollen lip could be an indication of an oral cavity tumor.

Some other symptoms that might occur are intense drooling, difficulty in swallowing, red gums, a cat’s refusal to eat, as well as weight loss.

The most common malignant tumor of the oral cavity that occurs in cats is squamous cell carcinoma, according to VCA Animal Hospitals. This tumor usually affects the cat’s gums and tongue.

Another form of tumor that occurs quite often is fibrosarcoma, which is very invasive and has a poor prognosis.

With these types of tumors, lesions usually appear in the cat’s oral cavity, which ulcerates.

How To Help?

A biopsy is required to confirm the diagnosis of an oral tumor in a cat. An X-ray is also important here, since it helps the veterinarian determine the size of the tumor. 

A biopsy of the lymph nodes determines whether the tumor has spread to the surrounding tissue.

Treatment of such tumors in cats refers to surgical removal. However, if the tumor has spread, such a procedure is very difficult to perform.

If possible, the veterinarian will recommend additional methods of treatment, such as chemotherapy and radiation. In addition, of course, the cat will need painkillers and supportive therapy.

Chances for recovery are highest when the tumor is detected and treated at an early stage.

Closing Thoughts 

A cat swollen lip could happen due to an allergic reaction, or a minor injury. However, it could also be a symptom of an underlying health issue, such as dental problems, the Eosinophilic Granuloma Complex, or even an oral cavity tumor.

Just to be sure, I recommend you take your cat to a vet clinic, or at least call your veterinarian and explain to him the symptoms you noticed in your kitten.

Whatever the medical reason for the swollen lip, the sooner you find the exact cause, the better it will be for your kitty.

Also, I remind you not to give any medicine to your cat before consulting your veterinarian, especially not medicine intended for humans or dogs.


[1] Saverino KM, Reiter AM. Clinical Presentation, Causes, Treatment, and Outcome of Lip Avulsion Injuries in Dogs and Cats: 24 Cases (2001-2017). Front Vet Sci. 2018 July 6;5:144. DOI, Retrieved June 06, 2023.

[2] Hopke KP, Sargent SJ. Novel presentation of eosinophilic granuloma complex in a cat. JFMS Open Rep. 2019 Dec 16;5(2): DOI, Retrieved June 06, 2023.