Why is my cat's lower lip suddenly red? Is it an allergy or injury?

This is a common look for cats who are allergic to their food bowls -- if any of his bowls are plastic, I'd recommend switching them out for glass and washing daily (or at least every other day). It could be caused by other allergies or a bug bite as well, and often goes away on it's own. If switching bowls (if applicable) and giving it a week doesn't make it go away, I'd recommend a vet visit.

Hi, thanks for using Petco Pet Education Center, formerly Petcoach! Poor Steluta!! I agree, the most common reason for the swelling is likely an insect bite or other allergic reaction. If the chin is still swollen tomorrow or her attitude and eating habits change have her seen tomorrow by your Vet. The mainstay of treating allergic reactions are steroids in cats. I would want to have her mouth examined well first to be complete. I hope this helps and I wish Steluta a speedy recovery!

I’m glad to hear the Binx is doing well aside from this redness. I agree - I don’t see any evidence of swelling or discrete lesions. That said, this type of redness is more likely either irritation from food and water bowls, or some underlying allergies, particularly given his young age. Plastic and ceramic bowls are fairly porous and can harbor bacteria. If you aren’t already doing so, try using stainless steel or glass bowls, taking care to wash them daily. If the redness persists, your next option is to take Binx to his vet for an exam. Your vet may need to prescribe some medication to help get this redness under control. Given the location, I wouldn’t recommend trying any topical medication, as I wouldn’t want Binx to ingest any of it. I hope that everything goes well!

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.

The swelling could be caused by blunt trauma (for example if she run into something) or allergic reaction. If it is not bothering Kitty at all, is not itchy or painful when you touch it, I would leave it for another 2-3 days. Most of the mild swelling regardless on the cause should disappear within 5-7 days. If the swelling becomes itchy, painful or gets bigger, please take Kitty to your local vets for a check up.

She could have an eosinophilic granuloma which is common in cats and can be caused by an allergic response. The lesion may become ulcerated and is typically treated with a corticosteroid. If she has any fleas then she should be treated for fleas. You could also put her on a hypoallergenic diet and see if that helps. Try to find a low cost clinic or a vet that would take a payment plan so you can get her treated. If she just needs a corticosteroid then it shouldn't be very expensive. Hope she gets better soon!

It would be unusual for allergies to only affect one side (although cats are prone to 'eosinophilic plaques from hypersensitivities) and the cobblestone appearance of the inside of the lip is a little concerning. I recommend a full physical exam by your vet - they may wish to sedate him to take samples of the area to rule out sinister causes and to guide the most appropriate treatment