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What you need to know about your cat’s swollen lip – what caused it and how to help it heal

Causes and treatments of your cat's swollen lip

Your sweet feline friend is a wealth of enjoyment and entertainment — from funny sleeping positions to those precious purrs. Cat behavior can be somewhat of a mystery for even the most dedicated cat lovers, though, and those behaviors can lead to physical manifestations that puzzle us.

If you’ve ever looked at your cat and noticed a swelling on the upper or lower lip, here’s what you need to know: This common occurrence isn’t something to worry about, but it isn’t something to ignore, either. While your vet checks your cat’s health, you can read up on this confusing condition.

Calico cat with mouth open

Why is my cat’s lip swollen? There are many causes of this symptom, but it can be easy to diagnose

Swelling on the upper or lower lip happens often, especially for owners of young cats who love to explore and get into things. There could be a variety of causes for changes in your cat’s appearance, so the most important thing to remember is to get your cat checked and diagnosed by a vet you trust.

While you’re waiting for your appointment, let’s take a look at some of the possible conditions that could be causing your cat’s swollen lips.


Although they’re not the most common cause of swelling, there is a chance your cat is experiencing discomfort and swelling due to allergies. Animals can experience allergies just like humans, which can sometimes lead to symptoms such as swelling in soft tissues like the lips. Whether it’s food or environmental allergens like dust or certain materials, your veterinarian can help you narrow down possible causes and build treatments to help keep your cat comfortable and safe. If you’ve ever been tested for allergies, you know what we’re talking about!

Dental conditions

If your cat seems to be struggling with eating – -or avoiding it altogether — that swollen lip could be a symptom of an underlying dental issue. Sometimes, a dental abscess (an infected pocket in your cat’s gum) or patch of tooth rot will cause swelling that pushes the lip out. Your veterinarian may recommend a course of antibiotics to deal with the infection, or there may be a small surgery involved to remove the infected tissue or tooth and relieve the symptoms. Think of this as just one more reason to stay on top of your pet’s dental care.

Chin acne

Chin acne is another way to describe infected hair follicles on your cat’s chin. If they occur far enough toward the mouth, the swelling appears to be in the lips. There are several reasons that chin acne occurs, ranging from allergies to ingrown hairs. Your veterinarian can find the issue and recommend a topical treatment to handle the infection. Skincare isn’t just for people!

Eosinophilic granuloma complex

Eosinophilic granuloma complex may be a mouthful, but it refers to a pretty simple condition: when your cat has an allergic reaction to a bite from an insect like a flea, mosquito, or mite. The site of the bite can swell up, and it may be red and itchy. In some cases, the bite site remains small and barely noticeable, but in others, it can result in a large ulcer. Lesions often develop along your cat’s gums and in her mouth, though they can also be located on the hind legs and stomach. Your cat may lick and scratch at the lesions, so you may see hair loss, too.

Your vet can diagnose this condition with tests like a needle aspirate and a biopsy. He may prescribe medications to help control the condition, but other steps, such as implementing a flea control program and putting your cat on a hypoallergenic diet, may also help. Once your cat has developed this condition, she will be likely to get it again in the future, so prompt treatment and good management of this condition are important.

Cancer and tumors

No one wants to hear that word, but there is a small chance your cat has developed a tumor on the upper or lower lip that’s causing swelling. Again, your veterinarian can assess the swelling and determine if it’s a cancerous tumor or simply a growth. Various treatments are available, including surgeries, and your vet can help you determine the quality of life for your cat moving forward. This is most commonly seen in elderly cats.

Physical injury

It’s possible that your cat may have fallen and injured her mouth, resulting in the swelling that you’re seeing. This could have also resulted in tooth injuries and damage to the interior of your cat’s mouth that may need treatment. If you’re able, taking a peek at (or even in) your cat’s mouth can be super helpful.

Other causes

Sometimes the cause is straightforward and requires no further treatments. If it’s mosquito season, your cat may simply have a bite, and the swelling will go down in a few days. Your cat may have also sustained a minor injury or scratch that’s causing swelling. Watch the swelling for a few hours to a day to see if there are changes. If your cat will allow you, inspect the swelling site to see if you can see a bump, bruise, bite, or even an attached insect like a tick. Clean the area thoroughly if you can to help avoid further infections.

Woman petting cat

Symptoms associated with a cat’s swollen lip that you need to be sure to look for

If your cat has a swollen lip, you’ll also want to check to see if they are exhibiting some other symptoms as well, according to Natural Pets HQ. Additional symptoms could indicate that something more is going on. Be sure to look for things like:

  • Red gums
  • Scabs or sores around the mouth
  • Mass of any kind
  • Bleeding or oozing
  • Bad smell in their mouth
  • Drooling
  • Decreased eating or drinking

These are all signs that should prompt you to take your cat to the vet.

A close-up of a calico cat with a pink nose

Caring for your cat’s swollen lip at home and at the veterinarian’s office

If you’re saying to yourself, “my cat has a fat lip,” it’s essential for you to inspect the area and take precautions to ensure the site doesn’t get infected. If you suspect something more or you’re unsure of the cause for the swelling, it’s time to check with your vet.

Don’t ignore a swollen lip. Even if you suspect something minor, watch the area and seek medical attention for your cat if it doesn’t seem to improve in a few days. The underlying condition could be serious, and the earlier you diagnose it, the better chance your cat has to recover.

Cats don’t always show signs of distress or pain, so it’s up to you to watch your cat and learn what’s normal. If you notice something amiss, you can catch those symptoms early and do something about them. Your cat’s swollen lip isn’t just a pout. Keep an eye out for your sweet friend, and you’ll be able to enjoy the best life possible together. Those little symptoms are significant clues to your cat’s health and well-being, so be your cat’s advocate.

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