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What causes a lump or bump on my cat's back and what should I do?

Updated on September 23rd, 2025

Pet's info: Cat | American Shorthair | Male | 6 lbs

My cat has a lump or bump on his back

4 Answers

Most Helpful Answer

Answered By Dr. Melanie, BVSc MS

Veterinarian

Published on June 16th, 2018

If Yellow Cat is allowed outside, this lump could be an abscess. Cats who go outdoors can get into fights with other cats, and bites from other cats frequently lead to abscesses. These are very painful to the cat, and need to be sterilely drained and flushed, and oral antibiotics prescribed to treat the infection. Other causes of the lump include a cyst, a benign tumor, or a malignant tumor. I would have him seen by a vet first thing in the morning to have this lump examined and diagnosed so it can be treated as needed. Best of luck.

20Pet Parents found this answer helpful

Related Answers from Veterinarians

Answered By Dr. Davis
Veterinarian
Published on March 12th, 2018
From your description this sounds like an abscess or pocket of infection. Outdoor cats get these from fighting. You can use a hot compress on the area and massage it. If you find a scab I would remove it so the infection can drain out. If you can take him to a veterinarian they will sedate him and clean the area and give him antibiotics. Once the area has drained you can keep the wounds cleaned with hydrogen peroxide. If you are going to keep him I recommend neutering him so he’s not so prone to fighting. Thanks for using Petco Pet Education Center, formerly Petcoach to help you care for your cat.
1Pet Parents found this answer helpful
Answered By Sara Farmer, DVM
Veterinarian
Published on April 24th, 2019
I wonder if this lump is potentially an abscess. I would recommend having a veterinarian examine Loki sooner rather than later since he is in pain. They might recommend a fine needle aspirate which is a procedure where a small needle is used to take a sample to examine microscopically.
5Pet Parents found this answer helpful
Answered By Jenny, DVM
Veterinarian
Published on January 27th, 2018
If the growth is changing and growing it is worth having your vet check the area. They can take a needle sample of the mass and look at the cells to determine if it is a fatty tumor or something cellular that will need surgery. It is better to have it removed if it is small and caught early than wait until it is too large to address
1Pet Parents found this answer helpful

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Health & Wellness

Why does my cat have a hard bump on her back near her shoulder?

The most common lumps on cats are pockets of infection, or an abscess from a cat fight. An abscess is generally hot to the touch and painful and may cause a fever and lethargy. It also could be a tumor which often are non painful but can be malignant and will grow if not removed. Also some cats get a skin reaction to a vaccination if it’s given in that location and the swelling should improve over a week or so. I recommend a veterinary exam so they can feel the lump, take her temperature and decide if further treatment is needed. Thanks for using Petco Pet Education Center, formerly Petcoach to help you care for your cat.

Updated on September 23rd, 2025

My outdoor cat has a hard head lump and is acting sick. What is it?

It's likely that this lump is an abscess from a fight he had outside with another cat, you will need to take him to the vet in order to get it checked and treated, if it is an abscess it will need to be lanced and clean under sedation, he will also have an antibiotic injection to treat the infection.

Updated on September 23rd, 2025

Why does my cat have small bumps on his back and a large neck lump?

Hi there, it is hard to give you a specific answer regarding these bumps without seeing them, but I will try and give you some suggestions. If the lumps have just come up and feel soft they could be urticaria from an allergic reaction. Likewise if they are fairly new and are red or hot they may be caused by a skin infection. However, if the lumps have been there for a while again they could be infection but they could also be little growths in the skin. Have a good feel and if they are under the skin and soft they could be fatty lumps. If they are hard and in the skin they could be cysts, and if on top get may be warts. Unfortunately there is also the possibility the growths could be tumours. If you like you can repost with some photographs or more information and we can try and help more. I would recommend going to the vet to have he lumps checked f they have been there for a while. If they have just come up and don't look infected you could wait a day or so and give an antihistamine in case of allergic reaction.

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My cat came home with a spine bump. Should I worry? What to do?

If the swelling is warm to the touch and slightly depressible, then this is most likely an abscess (pus filled pocket) which is caused by some kind of trauma or puncture to the skin. This is a very common occurrence in cats that are outside or go outside for a brief period of time. To treat this you will need the help of your veteran veterinarian, who can drain the abscess and flush out all of the bacteria, and then put Dusty on a short course of oral antibiotics. Ask your veterinarian about an injectable antibiotic called Convenia, which they can give right there at the hospital. This antibiotic is favored by cat owners because it requires no medication giving at home and lasts for 2 weeks with just a 1-time injection by your vet.

Updated on September 23rd, 2025

Health & Wellness

What is this growing lump on my cat's face and is it serious?

This may be an abscess, a cyst or a tumor. You should have it examined by your veterinarian, as it is not possible to distinguish these by just looking at a photo. An abscess can usually be treated with antibiotics and/or be lanced, and a cyst can be evacuated. To identify a tumor, your vet may want to do a fine needle aspirate (he takes some material from the bump with a needle and then looks at it under the microscope) to determine whether the mass is concerning.

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My male cat has a painful lump on his stomach. What could it be?

Hi, thanks for using Petco Pet Education Center, formerly Petcoach! There are many possibilities, Bubby may have an abscess from a bit especially if he is an outdoor cat, it could be a mat of hair if he is a long haired cat or it could be a tumor. I recommend having him looked at tomorrow by your Vet. Good luck!

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My cat has a growing lump on his side and can't jump well. What is it?

I can understand being worried about TJ! I can see the lump from the picture you provided, and I have a few ideas as to what it may be. I see that he's not neutered, and intact males will frequently fight with other males for territory and females. If he's allowed outside, he could have gotten into a fight with another male, and developed an abscess from a cat bite. A cat's mouth has a lot of nasty bacteria in it, and abscesses are a common sequela to a cat bite. Abscesses are painful, so that may be why he's having trouble jumping on the bed. He could also have a cyst. Given that this lump is getting larger and he's having trouble getting onto your bed, I feel a vet visit in the morning is in order. The vet can diagnose what is causing the lump and how best to treat it. If he does have an abscess, it will need to be drained and flushed, and he will need antibiotics to treat the infection. I hope this helps!

Updated on September 23rd, 2025

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