What Causes a Cat's Swollen Lip?

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What Causes a Cat's Swollen Lip?

Cats are masters of emotional manipulation. However, if one day you notice that your feline friend looks like they're pouting, there's likely to be a medical cause there's likely to be a medical cause for this change in your cat's health. A cat's swollen bottom lip isn't part of a sulking act; it's a symptom that needs a veterinarian's care. Whether your cat's swollen lip is from an allergy or dental problem or is a tumor, your veterinarian is the one who can diagnose the problem and recommend treatment. If your cat has swollen lips, make a veterinarian appointment promptly.


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Why is my cat's lip swollen?

There are many possible causes for a cat's lip to be swollen, ranging from an injury to cancer. Usually, you cannot determine the underlying cause by simply looking at the lips, which is why it's important to contact your veterinarian if you notice swelling on one or both of your cat's lips. They will do a complete exam and diagnostics, possibly including X-rays, allergy testing, and biopsies.

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Understand eosinophilic granuloma complex

Sometimes, a cat's immune cells malfunction and react as if parasites have invaded the cat's body. These particular immune cells are called eosinophils. The condition that results is termed eosinophilic granuloma complex. There are many potential causes for allergic reactions that can cause an eosinophilic granuloma to form. These include bites from actual parasites, such as mosquitos, fleas, or mites, but your cat could also have a food allergy or other allergies. If your pet has this type of lesion on or near their lower lip, it will likely be red and itchy.


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Look for dental abscesses

Your cat's swollen bottom lip could be caused by a dental abscess or other tooth problems. An abscessed or broken tooth or another infected sore in a cat's mouth can cause swelling of the lips or face.


If an oral issue is the problem, you might notice other signs too. A painful mouth makes it difficult to eat, so your pet might seem to lose their appetite, or they might drop food from their mouth while attempting to eat. Irritable reactions when you rub or scratch their chin, drooling, head shaking, and worse than normal "kitten breath" are all signs that your cat's swollen lip could be caused by a dental infection or another dental issue.


Observe other swelling causes

If dental disease and granulomas have been ruled out, there are plenty of other medical issues that could cause your cat's swollen bottom lip or swollen top lip.



Feline acne is a condition that causes blocked pores and swelling of the upper lip and swelling of the lower lip and chin when pores are blocked by sebaceous glands under the chin (similar to human "blackheads"). You may also notice small scabs in the area. Feline chin acne might seem trivial, but it can be very uncomfortable for a cat, and it should be treated by a veterinarian. In the meantime, switching to stainless steel food bowls and water bowls instead of plastic bowls could help your cat be more comfortable.


A cat's lips, face, or entire head could swell as a result of an allergic reaction to pollen or another inhaled allergen. Sometimes food or even medications, such as antibiotics or heart medications, can cause an allergic reaction.

If your feline was bitten by another animal or took an awkward tumble and landed on their chin, the physical trauma could cause swelling. An untreated wound could also develop a bacterial infection. Skin infections sometimes ooze pus, which could contribute to the area appearing even puffier.


Squamous cell carcinoma, a particular type of cancer that causes oral tumors, can make a cat's lower jaw and upper lip or lower lip swell too. This can happen to cats of any age, but it's more common in older felines.

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What to do about a cat's swollen lip

When you notice any physical abnormality in your cat, an immediate trip to the veterinarian is a wise move. Always consult an experienced veterinarian regarding the health and treatment of your cat. The veterinarian can pinpoint the cause of the swelling and prescribe medication and treatment to alleviate discomfort.

If the swelling is due to an allergic reaction, the allergens can make breathing difficult for your kitty and can result in anaphylaxis, which is life-threatening. If left untreated, broken teeth and other oral problems can result in further oral issues as well as heart, liver, and kidney disease. There's no such thing as a wasted trip to the veterinarian, especially when your kitty's health is at stake.

The bottom line

If your cat has a swollen lip, visit your veterinarian to get to the root cause. Swollen lips, whether upper or lower, on felines can indicate a wide variety of health issues, including allergies, cancer, or an acute injury. Cat dental problems can also contribute to swelling of the lips. Your DVM can help pinpoint what's wrong and prescribe the appropriate treatment.



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