my cats lip

Question
I have a 2 1/2 year old (rescued as a kitten, with me 1 1/2 years) Torti/Mix cat, Walden. She is an indoor cat.  I have no other pets in my home.  She is wonderful, happy, well-adjusted, smart, funny, fun.

Her upper lip edge seems to be eroding on one side.  It has not been swollen or red, though in the middle of the erosion, the flesh looks very pink (maybe raw?).

She eats dry food, Science Diet.  

Otherwise, I have not noticed any strange behaviors or problems.

I have searched the web, and come up with all sorts of things from cancer to rodent ulcer.  

Help!

Thanks,
Jana

Answer
Hi, Jana.  Yes, I was going to say rodent ulcer right away.  I assume you probably have found a great deal of information on these sores.  They're caused by an autoimmune disease called an eosinophilic granuloma complex.  And the most effective treatment usually is a cortisone injection.  I have a cat suffering from this disease, and one injection clears him up just fine.  It's been years since his last one.

It is important to treat rodent uclers promptly.  If left too long, it can progress to cancer.  In some serious cases that don't respond to steroids, surgical or cryogenic removal of the lesion is suggested.

Cancer IS a possibility.  A bacterial infection resulting from a scratch from her tooth may be possible, too.  Your vet should be able to give you a good idea of the problem with an exam, or perhaps a tissue biopsy.