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What causes a large bump on my cat's head that appeared overnight?

Updated On September 23rd, 2025

Pet's info: Cat | Mixed Breed | Female | spayed | 1 year old | 13 lbs

Hi our cat is about a year old and she was fine this morning but when I came home from work I noticed that she has this huge bump on her head. It is on top in the front and is affecting the shape of her eyes. She doesn't seem to be in any discomfort though and I'm just wondering what it could be...cats aren't clumsy enough to get a bump on their head from falling, are they? The bump is so large and it basically appeared overnight. Can you tell me what would cause something like this?

1 Answer

Most Helpful Answer

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Answered By Makenzie Kurth, DVM

Veterinarian

Published on May 15th, 2018

Thanks for using Petco Pet Education Center, formerly Petcoach. A picture might be really helpful in giving you a better answer but if I had to guess based on age, rapid onset, etc., I’d vote for an abscess (usually from another cat or wild animal but poking it could do the same). This is more likely if she goes outdoors and less likely (but not impossible) if she doesn’t. Other things could be fungal infection, cyst, or other possibilities. Either way, I suggest seeing your vet as soon as possible. He or she will feel it and decide whether to lance it. If it does appear to be an abscess, antibiotics will likely be prescribed. Hope this helps and best of luck to you and Kikitoo!

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