Author TB Thompson DVM has been a licensed, practicing veterinarian since 2000.
It surely is worrying when you first notice your cat’s lip is swollen. You want answers!
There are many causes that have a similar appearance. That’s why seeking professional veterinary care should be your first step to diagnosing your cat’s swollen lip. But there are a few things we see more than others.
The most common cause of upper or bottom lip swelling in cats is eosinophilic granuloma related to allergies. Parasites, immune-mediated disease, dental problems, and toxins can also cause lip problems.
In this article, we’ll cover the 10 most common causes of lip swelling in cats, how each is diagnosed and treated. Please consult your veterinarian for specific recommendations for your unique cat.
KEY POINTS
- Swollen lips in cats is often caused by a type of skin allergy.
- Left untreated, lip sores may become painful and infected.
- Treatment may require oral and topical antibiotics plus steroids.
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10 Causes of Swollen Lips in Cats
Let’s discuss ten of the things that cause lip swelling in cats…
1. Allergies and Eosinophilic Granuloma Complex (EGC)
Also known as EGC or “rodent ulcer,” this inflammatory condition is common in cats. Typical EGC lesions appear as a puffy, swollen top or bottom lip. Cats can also develop sores on their feet, legs and bellies.
Any cat can suffer from this problem. According to a paper published in the Journal of Feline Medicine and Surgery, “There is no age predisposition or well-documented breed predilection for the development of EGC lesions in cats.” (3)
Eosinophils are immune system cells that is activated in allergic responses. These cells flock to the affected area and cause swelling as they try to fight off an invader. The most common causes of allergic reactions in cats include:
- Food allergy
- Contact allergy (especially from a food dish)
- Flea bite sensitivity
- Mosquito bite hypersensitivity
- Atopy (pollen)
While veterinarians do have ways to test for some allergies, sometimes it’s a matter of removing exposure to various things and waiting to see if the symptoms improve.
Diagnosis: We employ biopsies and allergy testing to identify triggers.
Treatment: In the short-term treatment may involve steroids, antibiotics and topical therapeutics. Other considerations include strict parasite control and changing the diet to a hypoallergenic food.
Home Care: An easy step to take at home is changing the type of food dish you use for your cat. Plastic and stainless steel dishes are more likely to cause a skin reaction in cats. No matter what kind of food dish you use, start washing it with hot, soapy water between EVERY meal.
2. Demodex Mites (Mange)
Demodex mites live in cat hair follicles and can cause lip swelling, hair loss, and scabs. While some cats carry these mites without issues, others can develop symptoms. Unlike the common type, D. gatoi mites can spread between cats.
Diagnosis: Skin scrapings examined under a microscope reveal Demodex mites. Multiple tests may be needed and sometimes the mites can only be found with a biopsy.
Treatment: This problem may be treated with oral, injectable or topical anti-parasite medication.
More from NPHQ Veterinarian
Learn more about demodectic mange in cats…
3. Immune-Mediated Pemphigus
Pemphigus is an immune issue that breaks down skin cell connections, leading to sores and swollen lips. Sunbathing can worsen the condition.
Diagnosis: A tissue biopsy is needed to differentiate pemphigus from similar conditions.
Treatment: Getting pemphigus under control usually requires immune-suppressive drugs such as steroids or cyclosporine. (1)
4. Oral Tumors
Various mouth tumors can affect the tissues of a cat’s oral cavity and cause the appearance of lip swelling. Tumors may be benign or cancerous and it’s impossible to differentiate the two without a biopsy in many cases. (2)
Squamous cell carcinoma, fibrosarcoma and malignant melanoma are the most common oral cancers found in cats. All three carry a poor long-term prognosis.
Diagnosis: Biopsies and imaging, like X-rays or CT scans, are crucial for evaluating tumors’ nature and extent.
Treatment: Requires surgical removal or debulking followed by radiation or other anti-cancer treatments.
5. Skin Tumor
Cancers of the skin occasionally start around a cat’s mouth area. Mast cell tumors and cutaneous lymphoma can both cause a lesion that might look similar to more benign causes.
Diagnosis: A needle biopsy may be adequate in some cases. Other require an excisional tissue biopsy.
Treatment: Involves surgical removal or debulking followed by radiation, chemotherapy or other anti-cancer treatments.
6. Dental Disease
Dental issues are common in aging cats and can range from mild gingivitis to severe abscesses. Symptoms may even show up externally. Talk to your veterinarian to ease any concerns about treatment.
Diagnosis: Dental exams under anesthesia, complemented by X-rays, reveal the hidden extent of periodontal disease.
Treatment: An full dental treatment under anesthesia may involve tooth extraction and application of antibiotics to diseased teeth.
7. Infection
Skin infections sometimes affect the tissue of the face and lips. Bacterial infections and abscesses from Staph and Pasteurella are more common in cats who spend time outdoors. Fighting with other cats and other kinds of trauma are often the culprits.
Fungal infections like ringworm cause hair loss, redness, and sometimes crusting. I’ve seen cats with crusty ears, noses, and lips from ringworm infections. A simple culture will help diagnose ringworm.
Diagnosis: Culturing and sensitivity testing pinpoint the exact cause of infections and allow for targeted and effective treatment.
Treatment: Injectable or oral antibiotics based on culture and sensitivity.
8. Chin Acne
Should we call it “chacne?” In any case, this is a skin condition in which hair follicles on the chin area become plugged and inflamed. It usually looks like blackheads, dirty fur, reddish skin and sometimes a puffy lower lip.
Cat acne is often related to allergies and some of the same treatment methods are used.
Diagnosis: May be based on appearance and ruling out other similar diseases. Sometime a tissue biopsy is required.
Treatment: Oral, injectable and/or topical antibiotics. Follicle flushing topical treatments such as benzoyl peroxide.
9. Toxins
Some toxins cause significant oral irritation. These include household cleaning products like bleach and detergents.
Pothos Scindapsus and Epipremnum are tropical house plants that belong to the Araceae family. If chewed or ingested by a cat, Pothos can cause significant swelling of the cat’s mouth, lips and gastrointestinal tract.
It’s a good idea to avoid having Pothos and cats in the same home. If you want to have both, make sure the plant is in an area the cat doesn’t have access to.
Diagnosis: Based on a history of contact with irritants and appearance of lesions.
Treatment: Removal of irritating substance, often with water rinsing. Supportive care, pain medicine and possibly antibiotics if there are mouth ulcers.
10. Trauma
I’ve seen cats with face and mouth injuries from trauma. They can fall while climbing on tall bookcases. Housemate cats can bite and wound each other.
And of course, outdoor cats have all sorts of dangers to contend with: cars, dogs and untold numbers of sharp objects!
Diagnosis: Based on appearance of injury, history of exposure to trauma and X-ray imaging.
Treatment: Pain control, antibiotics, surgery as needed.
Expert Insight: The Critical Case of Fluffers
In my years of practice, a memorable case of lip swelling involved a cat named Fluffers. He was brought in by his owner for a routine steroid shot, who suspected a rodent ulcer was to blame for his swollen lip.
However, upon examination, the lesion’s characteristics—particularly its hardness and lack of scabbiness—raised a red flag. This presentation diverged significantly from the typical appearance of eosinophilic granulomas I’ve encountered.
Trusting my veterinary instincts, I recommended a biopsy to obtain an accurate diagnosis. The results were sobering: Fluffers had a cancerous tumor, not an allergy-related condition.
This case underscores the value of professional veterinary evaluation. Symptoms often mimic other conditions, and what might appear as a benign issue could signify a more serious underlying health problem.
Should Your Cat See a Vet?
Any abnormalities you notice on your cat’s face and head should be taken seriously. You should see a veterinarian if
- The symptoms persist beyond 48 hours
- Lesions are getting worse
- Your cat has other symptoms
If you notice your cat has bleeding, lethargy, weakness or trouble breathing you should see a veterinarian on an emergency basis.
Frequently Asked Questions (FAQs)
Summary
Remember, a swollen lip could be a sign of many different issues, so it’s best to consult your veterinarian for a proper diagnosis.
The proper diagnosis and treatment will save you money and time, not to mention getting your cat back to normal quickly!
