Cat’s bottom lip is swollen – what can you do about it?

What causes a cat to have a swollen bottom lip?

A swollen bottom lip in your cat occurs when there is an inflammatory reaction in the tissue of the bottom lip. This inflammatory response can arise from various causes. For example, your cat may simply have fought, resulting in a bruise of its bottom lip. But if a wound has arisen, it can become infected and then form an abscess. Your cat may also have been stung by an insect such as a bee or wasp. In addition, your cat may suffer from feline acne. And of course it can unfortunately also be cancer in older cats. The various causes for a swollen bottom lip in a cat are further elaborated below. If you want to know more about a swollen upper lip, you can find the information op that page. 

Causes for a swollen bottom lip in your cat


If your cat has damaged his bottom lip in any way, the tissue can swell quite a bit. This often occurs, for example, after a fight, after an accident with a vehicle or when he has fallen from something. During a fight you often feel very small scabs and scratches elsewhere on his body. In a vehicle accident, they often braced themselves with their nails. The blow has pushed them away and their nails are split or abraded at the tips. If your cat’s swollen bottom lip arose after an accident, it is wise to check whether there are no injuries in the rest of the mouth. So no crooked jaw due to a jaw fracture, broken teeth or wounds in his mouth.

cat with swollen bottom lip due to injuries.
wound infections or abscesses

If there has been a wound, there is a good chance that a bacteria has settled in this wound. This bacteria can multiply, causing a wound infection. Your cat’s body will then send all immune cells to that infection. We also call them neutrophils or pus cells. All those pus cells along with the bacteria cause an abscess to form on your cat’s bottom lip. This abscess is a pus-filled cavity that you recognize as a swollen bottom lip in your cat. It will burst open after a few days, releasing all the pus and junk. But until then you will see a swollen bottom lip on your cat. Usually this swollen bottom lip in your cat is also quite painful. It feels like a softer “cushion”.

Insect sting

Most cat owners recognize it. Young cats in particular enjoy chasing a flying insects. In many cases this does not hurt, but occasionally that flying creature is a wasp or a bee. And yes, they can sting once caught. The lips, cheeks or tongue may then swell from the sting. That swelling in itself is quite annoying, but it can’t hurt that much. It will be the cause of a swollen bottom lip in your cat.

However, in some cases, a cat has an allergic reaction to it, which can cause the swelling to become quite large. And in some cats, that swelling can spread over the entire head and inside of the mouth. There is a chance that his airways will be blocked and your cat will no longer be able to breathe. So do you see a thick swelling that increases in size every 15 minutes? Then go to a vet urgently so that he can give your cat an injection against the allergic reaction. Most likely, your cat’s swollen bottom lip will also become less.

This cat will have a swollen bottom lip after the wasp stings.
Feline acne

This is a common condition that causes a swollen bottom lip in your cat. The first time they have this, they are often only a few years old. Their bottom lip, especially the bottom of the chin, becomes thick, some pimples or fluid blisters appear, which then open and form a crust. Sometimes the chin is only a little thick, sometimes it is very swollen. The original cause of this is usually not traced. But for some reason the hair follicles become inflamed and infected, which can eventually inflame the skin of the chin as a whole. And because of this you see a swollen bottom lip in your cat.

Cat with a mild form of feline acne as a cause for his swollen bottom lip.
Mild case of Feline Acne.
Tumors and cancer

It’s not very common on a cat’s bottom lip, but occasionally we see an older cat with a swollen bottom lip due to a lump on its chin. This hardly ever occurs in younger cats. In this case it is important that your vet takes some cells from the nodule with a needle. The laboratory can then determine whether the cause of your cat’s swollen bottom lip is a tumor and if so, whether it is cancer. If this is the case, it is important to start treatment as soon as possible.

Treatment of a swollen bottom lip in your cat

Treatment for your cat’s swollen bottom lip depends on what’s causing it. Below is a description of what you can do best for each cause.


Does your cat have a swollen bottom lip due to an injury? Then it is important to see whether his jaw is otherwise in order. There should be no abnormal movement of the jaw, nor should he have obvious pain when chewing. Does that seem okay? After that you can take a good look in its mouth to see if you see any blood or broken teeth. Do you not see any obvious deviations? Then give your cat something to eat that he can pick up well with his thick lip. If he eats normally otherwise, the chance of a fracture or other problems is small.

You don’t need to treat your cat’s swollen bottom lip unless you see a wound on it. In that case, put some iodine on it to disinfect the wound. The iodine ointment is the easiest for this, but you can also use the solution. Then keep a close eye on your cat’s swollen bottom lip. This should start to get less thick after a day or 2-3. Tip: take a picture of the swelling on day 1. You can then compare this with the days after that.

Wound infections or abscesses

Is the cause of a swollen bottom lip in your cat a major wound infection or even an abscess? Then it is wise to go to your vet. He can then prescribe a course of antibiotics. If you don’t want that, you can see for yourself whether you see a weak spot in the middle of the swelling. That’s where the abscess will burst open. If your cat allows it, try squeezing the abscess like a pimple in the direction of that weak spot. Don’t be alarmed by the amount of pus and junk you see coming out if the abscess opens. It also doesn’t smell too fresh I can tell you. If that doesn’t work, or if you don’t see a weak spot yet, you can wait another day and see if you can see it the next day and if you can push the abscess open.

As soon as the abscess has opened you have to push it empty 2x a day, until no more junk comes out and the swelling gets less every day. Usually this is the case after a day or 3. After emptying, you can apply honey ointment such as Vetramil. So you have to do this 3 times a day. This prevents the pus from irritating the skin on the outside and has a wound healing and antibacterial effect. Is the swelling not clear after a week or does it keep coming back? Then your cat really needs an antibiotic cure. And unfortunately you have to go to your vet for that.

Insect sting

If the swelling from the insect sting is not more than half a cm and does not get bigger within an hour, you can just wait and see. Your cat’s swollen bottom lip is probably itching or hurting him. But as far as the cure is concerned, you don’t have to do anything about it. This will resolve itself. Unfortunately, not every cat has learned from this experience, so don’t be surprised if your cat gets this again. To counteract the itching, you can use Douxo S3 calm mousse.

But do you see that the swelling has doubled in size within fifteen minutes? And does it still keep increasing in size? Then your cat has an allergic reaction and you need to go to your vet urgently. So also on weekends or evenings. This will incur additional costs, but there is a chance that your cat’s throat will swell to the point of suffocation. That doesn’t seem worth the risk to me, so it’s best to go to your vet with this swollen bottom lip, or in fact his whole face, on your cat.

Feline acne

So, with feline acne, there is an inflammatory reaction of the hair follicles, and then of the entire skin of the bottom lip and chin of your cat. One cat has mild complaints and you hardly see a swollen bottom lip in your cat. The other has a chin almost bigger than the cat’s head. In order to treat this problem you need a strong anti-inflammatory medication. I prefer hydrocortisone cream for it. But that is not all. There are also bacteria growing in the small wounds on the chin. So anti-bacterial treatment is also necessary. You can use chlorhexadine whipes for this, which will stop bacteria from growing. 

First you whipe the swollen bottom lip and chin with the chlorhexidine whipe and let it dry for about 5 minutes. After that you put on the hydrocortisone-cream. You do this 3 times a day for at least 7 days. But in many cats it takes longer. In any case, continue ointment for at least 3 days longer from the moment your cat’s chin appears to be completely healed. Stopping too early will cause the swollen bottom lip to come back quickly. You should see some healing of his chin and bottom lip after about 3-4 days. 

Tumors and cancer

It goes without saying that if you see a swollen bottom lip in your older cat, it is important to see your vet for further investigation. If it is indeed cancer and you still want some treatment for your cat, then speed is important. The longer you wait, the bigger the chance that the cancer has spread and then there is not much left to treat.

Your vet will aspirate some cells from your cat’s swollen bottom lip with a needle. These cells can be sent to a special laboratory where (hopefully) a diagnosis of the fat lip in your cat will be made. If it concerns cancer, it will have to be surgically removed. In many cases, this removal is not sufficiently possible because there just isn’t enough skin.  Most of the time additional chemotherapy or radiation is required. But in a lot of times it is unfortunately the case that owners no longer want this for their older cat. In the long term, euthanasia will then be chosen.

Hopefully a soon recovery

Hopefully, this article has given you enough information to help your cat with its swollen bottom lip. He’ll probably be your handsome furry friend again soon. Good luck!