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

From the photos it looks like Xena has a "rodent ulcer" (aka: eosinophilic granuloma complex). It is best to have her checked out by your regular veterinarian to get a definitive diagnosis and treatment. ( https://veterinarypartner.vin.com/default.aspx?pid=19239&id=4951528 ) Hope this helps. Best wishes.

Hi, and thanks for your question. This could be due to an allergy, although it could also be infection or mites. I don't think it looks like an ulcer. First of all, in order to rule out skin parasites, you will need to treat with a high quality flea treatment, then ask the vet to perform a skin scrape - this might reveal an infection or a mite infestation. If all of those came back negative, the next step is to treat the allergy symptomatically and try to discover the cause of the allergy. Three main type of allergies are usually affecting pets: food allergies, flea and parasite related ones and environmental type (allergens coming from trees, pollens, dust etc etc). Some medications can be given by the vet in order to repair any possible skin lesions (like steroids and antibiotics). Hope this answer was helpful, but please do not hesitate to contact us again on the forum or by requesting a consultation if you have any more questions or to discuss it any further. If this answer was helpful please let us know, this will be used to improve our service!

Looks like a condition called esosinophilic granuloma complex which can occur in cats. It appears like it should be very painful. If you notice he is eating or grooming less, these are signs he is uncomfortable. Sometimes this is caused by an allergy. I would recommend changing food bowls and try a hypoallergenic diet. Ultimately seeing your veterinarian to have a biopsy performed to confirm the diagnose and starting some medications will be needed to help resolve the swelling. Good luck !

Thank you for submitting your question regarding Cleo. I recommend that she sees her veterinarian. Her lip lesion appears similar to a condition known as an indolent ulcer. This can be the result of an allergic disease such as to her diet or fleas. She needs to be treated soon as if this is the case, the lesion can be harder to heal the larger it gets. I hope this information helps!

This appears to be what is commonly referred to as a 'rodent ulcer'. The most common cause for these to pop up in cats is an allergy, typically to something in the food. Sometimes these will resolve in their own, however sometimes they can become infected, long lasting, and problematic. If they become very large and painful it can discourage the cat from wanting to eat. If this ulcer has been present for more than 2 weeks it is probably not going to go away on its own. At that time I would recommend taking you cat to the vet for treatment. Nathaniel may need antibiotics and an immunsuppresive drug like steroids or Atopica. If the lesions keep coming back he may need to be on an immunosuppressive long term and/or a hypoallergenic diet. I hope this helps. Thanks for using Petco Pet Education Center, formerly Petcoach. Best of luck.

That looks like some sort of an ulcer on Mickey’s lip. This is generally related to an allergic reaction, a tooth root abscess or an immune mediated disease. Have Mickey examined by his veterinarian who may get a clue to the cause from the rest of the physical exam. He will likely get medications to heal the ulcer quickly. He does need to wear an Elizabethan collar at all times to protect the wound from any further trauma. I hope this helps and best of luck.

The lesion on Bamboo's lip is quite prominent. It could be due to infected hair follicles, an indolent lip ulcer (although the photo does not quite look typical of this), or a benign or malignant mass. Since this lesion has grown fairly rapidly over just a day or two, she should be examined by a vet sooner rather than later. The vet will likely need to perform a fine needle aspirate, whereby they will draw out a sample of cells with a needle (it's quick and relatively painless!) so that they can be examined microscopically. From there, the vet will be able to determine if Bamboo should be started on a course of antibiotics or if she will need to have this lesion surgically excised. I hope that all goes well!