8 Strange Reasons Your Cat’s Bottom Lip Is Swollen

Cats get a lot of sensory information using the extremely sensitive tissues in the area of their muzzle. Between their whiskers, skin and scent-producing glands this part of their body is pretty important.

Most cats are not too thrilled to have a human trying to look inside their mouth so many oral problems go undetected. But it’s pretty easy to see when a cat’s bottom lip is swollen. Top lip swelling is a bit harder to recognize. 

Eosinophilic granuloma complex is a common cause of lip inflammation in cats. But a cat’s swollen lip can also be a result of dental problems, cancer, infection or auto-immune disease. It can be hard for a cat owner to distinguish between these diseases, so enlist the help of a veterinarian.


What changes will I see when my cat’s lip is swollen?

Many cats with swollen lips have other physical symptoms. Take a good look at your cat and think about anything unusual you may have noticed over the past few months. Some of the symptoms that occur along with lip swelling include: 

  • Lower lip, chin or top lip puffy, inflamed
  • Scabs or sores present, may bleed or ooze pus
  • Gum inflammation/redness, foul breath odor
  • Lump or tumor present
  • Bald patches on chin or lips
  • Swollen chin
  • Small scabs on head
  • Rubbing or scratching mouth or face, head shaking
  • Changes in appetite and thirst
  • Dropping food while eating, chewing on one side only
  • Grinding the teeth, swallowing and/or salivating excessively
  • Swollen lymph nodes near the jaw
tabby and white cat swollen lower lip
Photo of a cat with swollen bottom lip by Lisa Zins (CC By 2.0)


What is the most common cause of lip swelling in cats?

Does your kitty look like Elvis smirking? If you look closely, you may see your cat has a swollen upper lip on one side. When the bottom lip is affected cats sometimes look like they have a really big chin or like their bottom lip is pink.

Eosinophilic granuloma complex (EGC) is sometimes called a “rodent ulcer,” is one of the most common causes of lip swelling in cats. EGC can cause puffy lip edges as well as sores on other areas of their body such as the lower legs, feet and abdomen.

Eosinophils are a type of blood cell that are stimulated in allergic reactions. As these specialized cells attempt to fend against a perceived threat, they collect around it and induce swelling. Skin allergy reactions are often caused by

  • Contact with certain materials such as metal
  • Fleas
  • Mosquitos
  • Food
  • Pollen and dust

Your vet may recommend allergy testing. But sometimes the best course of treatment is to limit exposure to certain things while watching to see whether the lip symptoms go away.

Changing the sort of cat food bowl you use is a simple thing you can do right away.

Ceramic or glass dishes are less likely to cause skin allergy symptoms. Also, you should start thoroughly washing your kitty’s food dishes after every meal, regardless of the type you use.

Do skin parasites cause lip swelling in cats?

There is a species of parasitic mite called Demodex that inhabits the hair and skin follicles of numerous animal species. The three types of Demodex mites that affect cats: Demodex cati, Demodex gatoi, and an unspecified type.

Many healthy cats may carry low numbers D. cati mites with no symptoms whatsoever while other cats develop skin inflammation from the mites. D. cati mites are not contagious but D. gatoi mites can transfer from cat to cat.

Demodicosis in cats may cause moderate swelling, hair loss, and small scabs on the skin. The  lesions usually affect a cat’s head and face areas. Skin scraping tests or biopsies can help your vet diagnose a Demodex problem.

Can a cat’s swollen lips be caused by immune-system disease?

An immune system disease called pemphigus causes the destruction of the structures that connect skin cells. Pustules, scabs, and swelling are some of the signs of pemphigus. Lesions may crop up on a cat’s lips or other parts of their body.

The best approach to identify feline pemphigus is with a skin biopsy. Most of the time, it’s not possible to identify an underlying cause of pemphigus. Depending on the type, feline pemphigus may or may not respond well to medical treatment.

cat yawning (cat's bottom lip is swollen)
Guaranteed this kitty has a few dental problems in addition to swollen lips!

How does dental disease cause lip problems in cats?

Dental disease is present in many cats and it’s occurence increases with age. Cats experience a range of dental problems from mild gum disease to stomatitis, all the way to tooth loss or resorption. Sometimes dental disease inflammation spreads to a cat’s lips and causes swelling. 

Your vet will need to perfom a complete oral exam and take mouth radiographs to assess your cat’s dental health. Anesthesia is always required, but the risks are relatively minor and proper dental treatment could vastly improve your cat’s quality of life. 

If you’re worried about putting your cat under for diagnosis and treatment of oral disease, be honest with our vet. They can walk you through the procedure and may even recommend ways to make it even safer. 

What if it looks like my cat has a growth on their lip?

Cats can be affected by several kinds of oral tumors. These tumors can make a cat’s lip look swollen. Not all oral tumors are cancerous, but it’s hard to tell if they’re benign or malignant without a surgical biopsy.

The top three types of oral tumors in cats are squamous cell carcinoma, malignant melanoma and fibrosarcoma. The prognosis for all three of these is poor over the long term.

Sometimes a cat’s lip swelling is caused by skin cancer. Cutaneous lymphoma and mast cell tumors can cause red, puffy skin that can mimic typical EGC. In order to diagnose these cancers, your vet will need to do a biopsy.

Is my cat’s lip infected?

Cats can get skin infections on any part of their body, including their lips. Infections from Pasteurella and Staphylococcus bacteria often occur in wounds cats get from fighting or other trauma. Outdoor cats are more likely to fight or sustain wounds and therefore tend to get more infections and abscesses .

Ringworm is a type of fungal skin infection that can spread from cat to cat (and to other animals). Symptoms of this fungal infection look similar to other types of dermatitis with redness, hair loss, scabbing and swelling. It’s possible for cats to get ringworm lesions on their lips and chin.

Why does it look like my cat has pimples on their lips and chin?

Some cats are prone to developing clogged skin pores on their lips and chin. These look like typical “blackheads,” also known as comedones. You may also notice a dirty appearance to the fur in the area and reddening of the skin. Sometimes a bacterial infection can develop in cats with acne, leading to the appearance of a swollen lip. 

The underlying cause of cat acne is unknown but is thought to be related to a hypersensitivity reaction (a.k.a. allergy). Treatment is based on cleaning the area, treating with antibiotics and topical medication, food allergy trials and improving food dish hygiene. 

Golden Pothos plant
Golden Pothos causes oral irritation when cats chew on it.

What toxins can cause lip swelling in cats? 

Many cats just love to nibble on plants. Most of the time, nothing disastrous happens but a few very common houseplants can cause mouth and lip swelling in cats. 

The tropical houseplants known as Satin Pothos (Scindapsus pictus) and Golden Pothos (Epipremnum aureum) are popular because of their low maintenance requirements. When a cat chews, licks or eats one of these plants they may develop significant oral swelling.

If you have cats, it’s smart to swap any Pothos plants you already have for safer ones like Silver Leaf Peperomia. If you really must keep a Pothos plant, keep it locked away from your cat. 


Investigate your home to collect information before making a trip to the vet clinic. Is your cat’s appetite or thirst abnormal? Have you changed cat litter in the last few months? Are there any new items the cat comes in contact with such as cat food, furniture, rugs or toys? Are the symptoms recurring? 

Your vet will probably recommend some diagnostic tests to figure out the best treatment. Tests for cats with a swollen lip may include

  • Skin scraping
  • Cultures for fungus and bacteria
  • Biopsy
  • X-ray imaging
  • Blood & urine tests
  • Allergy testing
  • Food allergy trial
  • Medication trial


How is a cat’s swollen lip treated?

When your cat’s lip is swollen, it’s best to determine the underlying cause. Based on their findings, your veterinarian will recommend a course of action for your pet.

Treatments for lip swelling depend on the cause and could include:

Eosinophilic Granuloma Complexsteroids, cyclosporine, parasite treatment, food allergy trial
Feline acneFrequent skin cleaning and topical antibiotics +/- benzoyl peroxide
Demodex mitestreatment with spot-on like Bravecto, or injectable ivermectin
Dental diseasedental xrays, full mouth cleaning, extraction of severely diseased teeth, +/- antibiotic therapy
Oral growth/massbiopsy collection and analysis, xrays, and therapies targeted to type of tumor

How much does it cost to treat a cat’s swollen lip?

The cost of veterinary treatment depends on if there are additional symptoms besides a puffy lip. For a straightforward case with EGC, your bill may be in the range of a few hundred dollars. The diagnosis and treatment of chronic skin conditions, dental conditions, or malignancies may cost five to ten times more.


The most common causes of lip swelling in cats are EGC/allergic skin reaction, feline acne and infection. These diseases respond well to appropriate treatment with many cats feeling better in a matter of days.

Other causes of lip swelling are harder to treat. Severe dental disease responds well to treatment but cost and time constraints are a concern for many cat owners. Some oral tumors can be removed or controlled with aggressive therapy.


Although it’s a common cause, you shouldn’t assume your cat’s lip problems are due to allergy or eosinophilic granuloma complex (EGC). There are other conditions that can resemble EGC quite closely.

Have your veterinarian examine your kitty and suggest a course of action. You’ll save money, time, and your cat will recover faster with the right diagnosis and treatment.

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