Swollen Lip in Cats: The 3 Main Causes You Need to Know

A swollen lip in cats can present in various forms, and the top three causes are indolent ulcers, lip granulomas, and dental disease. In this article, I will discuss the potential causes in more detail, along with the treatments and preventative strategies.

1. Rodent ulcer or indolent ulcer

One of the most common causes of a swollen lip in cats is what we call a rodent, or indolent ulcer. This type of swollen lip affects the upper lip and the inside, making it difficult to see when looking straight-on.

This swelling is a type of eosinophilic granuloma complex, which is an immune-mediated condition that affects the skin and mucous membranes.

✅ What does a rodent ulcer look like?

Indolent or rodent ulcers usually appear as a reddish, hollowed-out sore(s), with a crusting surface. They are most commonly located on the upper lip.

As these ulcers progress, they thicken and develop raised borders that will make the lips look puffy. The ulcers may change to an orange or tan colour. There can often be a bad odour associated with these.

As these become more uncomfortable, you may notice rubbing or pawing at the face. This will also contribute to the overall swelling of these lesions. With that, I have seen many cats not show any symptoms at all, despite our interpretation that it would be painful.

Unusually, they can also have these skin ulcers on the inside of the mouth, separate from the lips.

✅ What causes rodent ulcers in cats?

We don't know the exact cause, although it is believed that it is related to an allergy or anything else that would trigger the immune system. Environmental allergies, food allergies or insect bites, such as fleas (flea bite allergy), can cause rodent ulcers in your cat. Some cats may also have a genetic predisposition.

✅ Diagnosis and treatment

Diagnosing a rodent ulcer involves a thorough dermatological examination by your veterinarian. In some cases, and depending on severity, a biopsy may be necessary to confirm the diagnosis and rule out other conditions like cancer.

Treatment often involves managing any underlying allergies or sensitivities. This might include corticosteroids, such as prednisolone or other immunosuppressive drugs such as cyclosporine (Atopica®). In some cases, dietary changes to a restricted hypoallergenic diet may also be recommended, especially if food allergies are suspected.

2. Lip granuloma

Another common cause of swollen lips in cats is lip granuloma, also a part of the eosinophilic granuloma complex.

✅ Identifying a lip granuloma in cats

Lip granulomas in cats appear as firm, raised swellings on the lips, especially the bottom lip. They can sometimes be ulcerative and may look reddish or raw, but often only appear as a large swelling on the bottom lip, at the midline.

✅ What triggers lip granulomas?

Much like rodent/indolent lip ulcers, we don't understand the exact cause. We suspect there is an underlying allergy or hypersensitivty to environmental allergens, food allergies, or fleas. There may also be a genetic susceptibility.

✅ Diagnosis and treatment

Diagnosing a lip granuloma involves a thorough dermatological examination. Since these granulomas can be associated with allergies, your veterinarian may also recommend allergy testing or specialized hypoallergenic diet trials.

Treatment typically includes corticosteroids or other immunosuppressive medications to reduce the immune system response and inflammation. This may also involve changes in diet, flea control measures, anti-allergy medication, or modifying the cat's environment.

3. Dental disease or periodontal disease

When investigating swollen lips in cats, it's important not to overlook the role of severe dental and periodontal disease.

✅ The connection between dental health and swollen lips in cats

Periodontal disease in cats involves the inflammation and infection of the structures supporting the teeth, including the gums. As this condition progresses, it can lead to swelling of the gums and surrounding tissues, sometimes extending to the lip area.

✅ Signs of dental disease in cats

Apart from swollen or puffy lips, signs of dental disease in cats include foul-smelling breath, difficulty eating, drooling, and visible tartar on the teeth. In many cases, however, there are no distinct symptoms revealed by cats affected with dental disease.

In advanced cases, there may be loose or missing teeth, bleeding gums, and noticeable pain or discomfort.

✅ Why prompt treatment is important

It's very important to address dental issues, as they can lead to more severe health problems if not treated or not treated properly. Potential complications of not treating include infections that can spread to other parts of the body.

Also, despite what your cat may not reveal, severe dental disease is painful and uncomfortable, which can affect their overall behaviour and quality of life.

✅ Treatment and prevention

Treatment typically involves professional dental cleaning by your veterinarian and may require tooth extractions in severe cases. Your veterinarian may also prescribe antibiotics and pain relief medications.

Preventive care is equally important. Regular dental check-ups and good oral hygiene practices, including brushing your cat's teeth, feeding dental kibble, or using dental treats and toys, can help prevent the onset or progression of dental disease.

FAQs

In closing, swollen lips in cats can be symptomatic of conditions including rodent or indolent ulcers, lip granulomas, or severe dental diseases. Fortunately, a swollen lip in cats has a good prognosis, provided the cause has been isolated and treated.