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My cat has a lip blister getting worse. Is it an allergy or serious?

Updated On September 23rd, 2025

Pet's info: Cat | Mixed Breed | Male | neutered | 2 years and 2 months old | 10 lbs

I have a 2 year old male cat that has a blister that appeared on his lower lip. He is an indoor cat and only has been around one other cat. The blister does not seem to be bothering him but I am wondering if he is having an allergy to something. The blister has only been visible for the past 2 days but it seems to be getting worse. There are no blisters on the inside of his mouth. Does anybody know what could be wrong?

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1 Answer

Most Helpful Answer

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Answered By Dr Stafford, BVetMed, MRCVS

Veterinarian

Published on August 21st, 2018

I suspect he may be developing an ulcer due to allergy or eosinophilic granuloma complex. If the lesion is getting worse I would advise getting it examined by a vet asap as without prompt treatment these issues can become quite severe.

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