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Why does my cat's red, swollen lip keep flaring up and returning?

Updated on September 23rd, 2025

Pet's info: Cat | Mixed Breed | Female | unspayed | 7 months and 8 days old

My cats lip has flared up and gone red. This is the second time this has happened now however it went away after a few days the first time. I'm getting quite worried and need help. Thank you.

3 Answers

Most Helpful Answer

Jenna Beyer, DVM, MBA, cVMA

Answered By Jenna Beyer, DVM, MBA, cVMA

Veterinarian, Certified Veterinary Acupuncturist

Published on August 9th, 2017

The pictures are too dark and I can't quite see what you are seeing, however, a common cause of a swollen area on a cat's lip that can go away and come back is called Eosinophilic Granuloma Complex. Many times, these can be caused by allergies, such as environmental, food, flea, or other types of allergies. Often, steroids are needed to help these wounds resolve. I would take Monty to the vet for diagnosis and to discuss treatment options. Since it has come back, you may also want to discuss options for treating allergies to see if we can keep it from coming back again.
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Related Answers from Veterinarians

  • Answered By Linda G, MS, DVM

    Veterinarian

    Published on February 13th, 2019

    Hello. Tom has what is known as an eosinophilic plaque, or indolent ulcer. Most dermatologist feel these have an underlying allergy component, either to an environmental or food allergy, or more commonly, to fleas. If you are not using a consistent flea product on Tom, you really need to, even if you are not seeing fleas. Cats are such efficient groomers that they can eliminate a flea or two before anyone knows it is there. But the allergic stimulation still occurs. Genetic predisposition, viral & bacterial diseases have also been implicated. Unless the true underlying cause is found, the occasional steroid injection or the use of another product such as cyclosporin is very useful, & generally safe for cats. Thanks for using Petco Pet Education Center, formerly Petcoach.

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    1Pet Parents found this answer helpful

  • Answered By Jessica Desrosiers

    Veterinary Technician

    Published on July 13th, 2020

    Poor Boo! That does sound like an allergy. Some things to try with allergies that may not have been done yet include a food trial (this can take a few months to see results depending on if it's the case or not) to rule out issues with certain proteins or grains that could be causing the swelling, especially if it's the mouth affected, and allergy testing and medication through your vet or through a veterinary specialist -- this may be a way to determine if there is an allergy happening which may be benefited by using a daily allergy med to see if it helps reduce or resolve symptoms.

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    1Pet Parents found this answer helpful

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