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Here’s why your cat’s lip is swollen

Your sweet feline friend is a wealth of enjoyment from funny sleeping positions to those precious purrs. Cat behavior can be somewhat of a mystery for even the most dedicated cat lovers, and sometimes those behaviors 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. Have your vet check your cat’s health, and in the meantime, here’s what you need to know if your cat has a swollen lip.

Calico cat with mouth open
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Why is my cat’s lip swollen?

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 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, sometimes leading to changes 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.

Dental conditions

If your cat seems to be avoiding eating or having trouble eating, 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 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.

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.

Eosinophilic granuloma complex

Eosinophilic granuloma complex may be a mouthful, but it refers to a condition where 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 around them.

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.

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
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Symptoms associated with a cat’s swollen lip

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, a mass of any kind, bleeding or oozing, a bad smell in their mouth, drooling, and decreased eating or drinking. These are all signs that should prompt you to take your cat to the vet.

Caring for your cat’s swollen lip

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.

Final thoughts

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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