Rodent Ulcer in Cats (AKA OMG Why Does Your Cat’s Mouth Look Like That?!)
Whoa! Have you ever looked at your cat’s mouth and thought: Wait, what’s going on? Your poor cat’s mouth is about twice the size it should be! So, you go check it out and when you open your fur baby’s mouth…fear for Fluffy’s wellbeing seizes you.
If you’ve seen this severe swelling in your cat, it’s a jarring sight, right? Your first thought is probably, OMG, why does my cat’s mouth look like that? Then: Does it hurt? Is it contagious? Is he suffering? 😧
I totally hear ya. One day, I noticed that one of my boys’ (Malcolm) upper lip was grotesquely swollen and black! What. In. The. Actual. Frak?!
Your cat is experiencing what is (un)commonly known as an Indolent Ulcer or Rodent Ulcer. It’s scary for sure, but don’t panic. Let’s talk about rodent ulcer in cats.
So, What in the Heck is a Rodent Ulcer?
So, first off, the term “rodent ulcer” is extremely misleading. Back in the day, farmers used the term because their barn cats developed mouth ulcers after hunting rats. But we now know this type of ulcer is in no way, shape, or form, caused by rodents. However, it is a condition that isn’t completely understood. The proper name for it is Eosinophilic Granuloma Complex.
So, yeah….. let’s just stick with Rodent Ulcer. But now, science. 🤓
Eosinophilic Granuloma Complex consists of three different skin diseases in cats:
- Indolent Ulcer, AKA Rodent Ulcer (erosion of the upper lip)
- Eosinophilic Plaque (usually found on the abdomen and thighs)
- Eosinophilic Granuloma (usually on the lower lip or back of the thighs)
The focus of this article is the rodent ulcer. Notably, rodent ulcer is usually painless, although it can be disfiguring if left untreated. Also, rodent ulcers are not contagious so don’t worry about your other animals, if you have them.
Typically, rodent ulcers appear on the upper lip of your cat. In Malcolm’s case, his upper lip has eroded and his front teeth have receded, giving him a “vampire” appearance, and a lot of the time, his tongue sticks out. He also drools. A lot.
In addition, he has what looks like a red sore with little white blisters on his palate. Despite looking like it should be painful, Malcolm doesn’t have any problems eating, drinking, sleeping, playing, biting with those big ‘ol fangs, etc.
If allowed to advance, your cat’s lips can look like they’ve been chewed off! Worse, if left untreated, your cat could lose its lips altogether and even lose its nose so that its naval cavity, teeth, and gums are exposed! 🙀
What Causes Rodent Ulcer in Cats?
There are a lot of causes of a rodent ulcer and the exact cause if this happens to your cat may never be known. But basically here is what we do know:
- Allergies to food, flea, mosquito or mite bites, pollens, and other environmental factors (most common and often recurrent — like seasonal allergies)
- Feline leukemia
- In some cases, it may be genetic
- Autoimmune disease, which occurs when your cat’s immune system mistakenly attacks its own body
- Reaction to plastic or rubber food dishes, or excessive chewing on plastic
Eosinophil cells are white blood cells that are part of the immune system. They move around the body hunting for parasites or allergies. Rodent ulcer is caused when these cells overreact to a nonexistent threat.
In Malcolm’s case, it is an autoimmune reaction. Although he is highly addicted to chewing on plastic garbage/shopping/storage bags. 😉
How Are Rodent Ulcers Diagnosed?
If the ulcer looks like what your veterinarian typically expects to see on the upper lip, diagnosis is fairly easy with just a physical exam, which is common in most cases. If the ulcer(s) is located elsewhere, your vet may do a Fine Needle Aspiration. In case the FNA is unclear, your vet may do a biopsy.
How are Rodent Ulcers Treated?
If your vet is able to definitively diagnose the ulcer, you can treat it accordingly.
If an allergic reaction is the cause of the ulcer, changes in diet and/or environment usually clear it up. You can treat it with flea/tick treatments and a hypoallergenic diet.
You can also make sure that your cat isn’t eating or drinking out of plastic or rubber (or chewing on anything plastic). Only feed and water with glass or stainless steel.
More commonly, treatment is corticosteroids, which are available in several different forms. If your cat responds well to periodic injections, your vet will use a long-acting steroid. Unfortunately, for Malcolm, his mouth cleared right up in a couple of days after the injection, but the ulcer came back long before it was time to get another one.
In that case, your option is a daily treatment in the form of prednisolone, which can be administered via tablets or liquid. Malcolm gets liquid because it was impossible to try to get him to take a tablet. It does suck trying to get the liquid in his mouth (I have to wrap him in a towel), and he manages to let some spill out of his mouth, but at least he’s getting some of it! 🙏
So, yeah, I highly recommend tablet form if you can trick your cat into eating it in his food.
Another common drug used to treat rodent ulcer is cyclosporine (Atopica®). This medication is given orally. Malcolm has to take this in addition to the prednisolone. But it’s also a good treatment option if your cat can’t take steroids for whatever reason. But beware: this medication is $$$! A 17mL bottle costs me approximately $130!
In extreme cases, if the ulcer or ulcers are infected, your vet will use antibiotics in addition to any or a combination thereof of the treatments described above. There are also more holistic approaches for treating your cat’s rodent ulcer.
If you’re worried about having to administer meds to your cat, don’t. You can learn how to do it safely for both you and your kitty.
So What Does Your Cat’s Future Hold? The Prognosis of Rodent Ulcer.
First, the bad news: rodent ulcers recur or never go away at all, and your cat may need life-long treatment. The good news is that the side effects of prolonged treatment with corticosteroids are usually minimal, although they may cause weight gain.
Malcolm has been taking his medications for about seven years now. And except for the daily battle of actually getting the meds in him, he lives a perfectly normal life. And has kept his svelte figure in the process! 😻
So, if you notice a rodent ulcer in your own cat, while it’s incredibly alarming to see at first, don’t panic. Which I know is easier said than done. You’re worried that your fur baby may be in pain and suffering and/or that it might be contagious to your other critters if you have them.
And, remember, while the condition isn’t entirely understood, rodent ulcer in cats is painless, not contagious, and entirely treatable. And the solution may be as simple as a change in diet and/or environment.
But you do need to take your cat to your vet. If left untreated, your cat could be permanently disfigured to the point of an exposed naval cavity, and exposed teeth and gums.
Follow your vet’s instructions. Use glass or stainless steel to feed and water and make sure you’re giving medications, if applicable, properly, consistently, and at the right dose.
So while the term “rodent ulcer” sounds terrifying at first, your cat can live a healthy, normal life and you can enjoy your fur baby’s company for many years to come! 😺
