Recognising rodent ulcers in cats.

Recognising rodent ulcers in cats. Image: Pixabay

Rodent ulcers in cats: Unsightly sores with a misleading name

Understanding Rodent Ulcers: Rodent ulcers appear suddenly, often red and raised on the lip, but usually painless for cats.

Recognising rodent ulcers in cats.

Recognising rodent ulcers in cats. Image: Pixabay

Rodent ulcers, despite the name, have nothing to do with rodents and thankfully aren’t a serious condition. These are actually sores that appear most commonly on a cat’s upper lip.

While rodent ulcers have an unpleasant appearance and develop on a cat’s lip, Spruce Pets assures us they are generally not a cause for major concern and have no connection to rodents.

While they may look alarming, rodent ulcers are treatable and rarely cause discomfort to your feline friend. Let’s delve deeper into what causes these ulcers and how to get your cat the care they need.

What Exactly Are Rodent Ulcers?

Rodent ulcers, also known as eosinophilic ulcers or indolent ulcers, are a type of inflammatory lesion. This means they’re caused by an overactive immune response in the body. These ulcers typically appear as:

  • Reddish-brown in colour
  • Shallow with raised edges
  • Well-defined, often circular or oval
  • Located on the ventral side (underside) of the upper lip, near the canine teeth

What Causes Rodent Ulcers?

The exact cause of rodent ulcers is unknown, but several factors are believed to contribute:

  • Allergies: Some experts believe allergies to food, fleas, or environmental triggers might play a role.
  • Autoimmune Reaction: The body’s immune system mistakenly attacks healthy tissue in the lip.
  • Self-Trauma: Excessive licking or chewing at the area can irritate the lip and worsen the ulcer.

Signs Your Cat Might Have Rodent Ulcers

The most obvious sign is a sore on the upper lip, but other indicators include:

  • Crusting or scabbing around the ulcer
  • Minor bleeding from the ulcer
  • Repetitive licking or chewing at the affected area

It’s important to note that rodent ulcers are usually painless for cats.

Diagnosing Rodent Ulcers

A veterinarian can usually diagnose rodent ulcers with a simple examination of the sore. In some cases, they might recommend a biopsy (tissue sample) to rule out other conditions.


Treatment for rodent ulcers typically involves addressing the underlying cause and managing the symptoms. Here are some common approaches:

  • Corticosteroid Creams or Injections: These medications reduce inflammation and promote healing.
  • Antihistamines: If allergies are suspected, antihistamines can help alleviate itching and discomfort.
  • Dietary Changes: If a food allergy is a possibility, a vet might recommend a hypoallergenic diet.
  • Elizabethan Collar (Cone): This cone prevents the cat from licking or chewing at the ulcer, allowing it to heal properly.


Unfortunately, there’s no guaranteed way to prevent rodent ulcers. However, maintaining good overall health for your cat can help:

  • Regular Vet Checkups: Ensure your cat receives routine checkups to identify any potential health issues early on.
  • Parasite Control: Implement a regular flea and tick prevention plan to reduce the risk of allergic reactions.
  • Balanced Diet: Provide your cat with a high-quality, balanced diet to support their immune system.

If you notice a sore on your cat’s upper lip, consult your veterinarian for a proper diagnosis and treatment plan. With prompt intervention, rodent ulcers can be effectively managed, ensuring your feline friend feels comfortable and looks their best again.


Artificial Intelligence assisted in compiling this article.