Why Is My Cat’s Lip Swollen?
Noticing swelling on your cat’s lip can definitely catch you off guard and present some concerns. Sometimes it’s as simple as having feline chin acne or a mild bite. But a swollen cat lip can also be linked to dental trouble, allergies, or an infection, which is why it’s worth paying close attention.
Upper or Lower Swollen Cat Lip?
Where the swelling shows up can give you some clues about what’s wrong. For example:
- Cat with lower lip swollen: If you’re seeing that your cat’s lower lip is swollen, this often points toward dental problems or chin acne.
- Upper lip swelling usually relates to insect bites, allergies, or eosinophilic granuloma. (This is just a fancy term for inflammatory skin sores) (1). Upper lip issues tend to be more common in younger cats. We all know how these curious ones love exploring and sticking their faces into everything.
Next, the most helpful thing you can do is figure out what’s causing the swelling. Then you can address it properly. We’ll give you some pointers below.
Common Causes of Swollen Lips in Cats
Let’s walk through the most common reasons for a cat to experience a swollen lip. We’ll also cover what you can do about each one.
Eosinophilic Granuloma Complex
Eosinophilic granuloma complex is one of the more common causes of a swollen cat lip. People often call it EGC for short. (1) This condition is really just a group of inflammatory skin problems. It shows up in three different forms: indolent ulcers, eosinophilic plaques, and eosinophilic granulomas (2). Sometimes people incorrectly call indolent ulcers “rodent ulcers.”
What It Looks Like
When EGC affects the lips, you’ll typically see ulcerated sores on the upper lip. They can occasionally pop up on the lower lip, too. These sores vary quite a bit. Some are small and barely noticeable. Others can be large, widespread lesions that distort the lip (1). This creates that swollen appearance. Some may bleed. Sometimes, you might even notice a lump near the cat’s mouth.
What Causes It
Most vets believe that EGC stems from allergies. This means that the cat’s immune system is overreacting to something (2). However, pinpointing exactly what’s triggering it isn’t always possible. The usual suspects include flea allergies, food sensitivities, and environmental allergens. Think pollen or dust mites. Sometimes, the condition starts as a reaction to something external. But once the cat starts scratching or licking, internal skin proteins get released. Then the reaction keeps going (3).
Treatment usually involves short-term anti-inflammatory medications. Steroids are common; they calm down the immune response (1). This reduces swelling and soothes the skin. Your vet might also suggest trying to identify whatever is triggering the allergy. Only then can you eliminate it.
Dental Issues and Abscesses
If your cat’s lip looks swollen and they’re off their food, dental problems could be the culprit. The cat can experience trouble eating if that’s the case. Interestingly, tooth root abscesses are surprisingly common in cats (4). However, they can cause serious swelling that pushes the lip outward.
How It Happens
When a tooth breaks or cracks, bacteria from the mouth can sneak in. As such, this problem can happen from chewing hard objects or trauma (5). The bacteria enter the exposed root canal. The problem is that cat tooth enamel is incredibly thin. We’re talking 0.1 to 0.3 millimeters. That’s about as thick as a few sheets of paper (5). Sadly, this makes it easier to fracture than you’d think. Once bacteria get in, they spread around the tooth root. This causes infection and inflammation. Sometimes, it actually kills the tooth.
Also, you might notice swelling below the eye if an upper tooth is affected. Those roots sit right beneath the eye (6). Such swelling sometimes gets mistaken for an eye infection. Please reach out to your vet if you suspect a dental abscess. These are painful for your cat and need treatment quickly (4).
Treatment typically means removing the tooth under anesthesia. A vet will also likely prescribe pain medication and antibiotics (4). Sometimes, if saving the tooth matters, a specialist can do root canal therapy as well.
Feline Acne
Sometimes what looks like lip swelling is actually chin acne, which can spread toward the mouth. Feline acne happens when hair follicles on a cat’s chin get infected or blocked (7). This works just like human acne by creating bumps, blackheads, or pustules. As a result, these can swell and spread. Therefore, feline acne is a particularly common cause when a cat’s lower lip appears swollen; it extends from the chin area. Several things contribute to chin acne: allergies are one factor, and so are ingrown hairs.
Why Food Bowl Choice Matters
Even your choice of food bowls matters because plastic bowls develop tiny scratches that trap bacteria. This is why many vets suggest switching to stainless steel (7). Ultimately, stainless steel is cleaner and easier to look after.
To reduce bacteria, try the 
Injury or Trauma
Physical trauma is often the first thing to consider with sudden lip swelling. Perhaps your cat bumped into something. Or, they could have gotten into a tussle with another animal. Or maybe they hurt themselves while exploring. You can look for other signs and check for blood, visible wounds, or pain when you touch the area.
Minor injuries from bug bites usually heal on their own. Small scratches do, too. This typically takes a few days. Still, keep a close eye on the swelling for the first few hours because you want to catch any changes.
Allergic Reactions
Although not as common, allergies can definitely cause facial and lip swelling. Food allergies are one trigger, and environmental allergens are another. Medication reactions can also cause this problem (2). Your vet can help identify what’s causing the reaction, and they’ll also help keep your cat comfortable.
Tumors (Less Common)
Though it’s the least likely explanation, tumors can occasionally develop on a cat’s lip. Both harmless growths and cancerous tumors are possible (8). If your vet suspects a growth, they’ll first examine it, and then they’ll figure out whether it needs treatment.
Interestingly, exposure to cigarette smoke has been linked to higher cancer rates in cats. Certain flea collars have, too (9). This includes oral cancers. Several treatment options exist for tumors, with surgery being one option. So, consulting your vet for a proper diagnosis matters.
Home Remedies for a Swollen Cat Lip
When dealing with a swollen cat lip, sometimes the cause seems obvious. For example, it might be a minor scratch or bug bite. And if your cat is acting normal otherwise, you can typically offer gentle care at home. Please, just keep monitoring things and don’t hesitate to call your vet for guidance.
Cleaning the Area
If you can safely look at the swollen spot, and your cat will tolerate it, try these steps:
- Gently wipe with a damp cloth to remove debris
- Apply a warm compress for five to ten minutes (this soothes swelling)
- Use a vet-approved antiseptic like chlorhexidine if your vet recommends it (it’s an antibacterial cleanser)
Please skip harsh chemicals or regular soap because these irritate the skin. They can actually make swelling worse.
Keep an Eye on Things
It’s best to check your cat regularly to make sure no new symptoms pop up. Watch for:
- Pus or discharge from the mouth
- Fever, sluggishness, or appetite loss
- Worsening swelling or spreading redness
- Trouble eating or drinking
- Signs of pain or distress
As a caring pet owner, please don’t ignore any condition that doesn’t get better with common-sense care. Also, please don’t ignore anything that gets worse either!
When to Contact Your Vet
It’s always smart to call your vet when you first spot swelling. It helps if you can let them know whether it’s the upper or lower lip that’s causing trouble. This helps them figure out what’s likely going on and also helps them decide what to do next.
When It’s Urgent
Please seek care right away if any of these apply:
- The swelling is severe or getting bigger fast
- It’s affecting your cat’s ability to eat or breathe
- You see discharge, bleeding, or smell something foul
- Your cat seems painful, feverish, or is acting strangely
- The swelling lasts more than a few days without improving
- You can see a wound, ulcer, or growth
What Your Vet Will Do
Your vet will examine your cat thoroughly, and they may suggest tests like dental X-rays. Cytology is another option (this means looking at cells under a microscope). Sometimes they’ll do a biopsy to confirm what’s going on (10). The treatment that follows will ultimately depend on the cause. Options might include antibiotics, anti-inflammatory medication, or allergy management. Dental work or surgery are other possibilities.
How to Prevent a Swollen Cat Lip
You can’t prevent every case of lip swelling. But you can lower the risk by building healthy habits for your pet:
- Brush your cat’s teeth regularly and schedule professional cleanings
- Use stainless steel bowls and wash them after each meal
- Keep your cat on flea prevention year-round if allergies are an issue
- Reduce exposure to allergens when you can
- Schedule regular vet checkups to catch issues early
- Keep your cat indoors to avoid trauma and bug bites
Final Thoughts on Dealing With a Swollen Cat Lip
Many things can cause a swollen cat lip. Some are mild, like chin acne or insect bites, while others are more serious, including dental infections, allergies, or skin conditions. The location of the swelling often provides helpful clues. Still, if the swelling lasts or gets worse, your vet should examine your cat to keep them on a healthy track.
References
- VCA Animal Hospitals. (n.d.). Feline eosinophilic granuloma complex in cats.
- Cornell University College of Veterinary Medicine. (n.d.). Eosinophilic granuloma complex.
- Brooks, W. (2020). Eosinophilic granuloma complex in cats. Veterinary Partner.
- Kanwal, M. (2023). Cat tooth abscess. PetMD.
- Vetster. (2024). Dental abscesses in cats: Causes, treatment and associated conditions.
- VCA Animal Hospitals. (n.d.). Tooth root abscess in cats.
