swollen area on butt, missing fur

Hi All,
I noticed tonight that my cat has an area on her butt where she has licked off her fur, and the skin is swollen and bruised looking. She has had skin problems before due to allergies, but they were just little black spots like zits on her chin, nothing like this. It looks almost like she hurt herself, except that she has been acting normal and playing. I'm taking her to the vet as soon as they open in the morning, but just wanted to ask if any of you had seen this before. Does it sound like allergies?? Thanks.

It sounds like an abscess forming to me. I bet she has an infection there, which could have been caused by a number of different things.

If she has allergies that affect the consistency of her bowel movements, this could lead to an impacted/abscessed anal gland. I don't know if the swelling is in the right area to be this, but it is a possibility.

Good thing you are taking her tomorrow.

I dont know what it could be, I have a couple things that come to mind, but I bet the vet will give you a better answer!

One possibility is an infected anal gland.

What does the area without the fur look like? Is it wet/moist or is it dry dry/flakey? Bite marks?
Dermatology is one of the hardest fields to correctly diagnose.

Went to the vet this morning, it was an abscessed anal gland. The vet said that it had ruptured on its own, which was why she was licking it so much- to clean it. She gave me a solution to clean the area and antibiotics. We're going back in a week to make sure it is healing correctly. I never would have thought of that on my own because I thought that was only a problem for dogs. Now in the future, if I notice her licking the area more than normal or anything else unusual, I will know to call the vet.

Thanks for your comments!

Wow, I guessed right!

But I wouldn't have, had it not happened to one of my brothers cats last year.