my Siamese has a sore next 2 her anus

Question
Hi, Jessica my Siamese has been grooming her bottom more than usual. I noticed a small sore on the left side of he anus. I'm wondering what could have caused this & what should I do?
My cat is female, just 3 yrs. old in March & indoor only (unless she's in her cat condo.)
Any help would be greatly appreciated.
Thanks in advance, Carole  

Answer
Hi Carole.  It's tough to say if the sore occurred first and is causing the excessive grooming, or if the excessive grooming caused the sore.  She may be having discomfort in that area due to diarrhea or constipation or parasites that is causing her to groom there.  Or she may have a fecal burn that she's tending to, caused by feces that stuck to her rear-end.  You should get her to a vet.  A sore in this area is at great risk for serious infection.  A vet will likely recommend that you soak the area with an antiseptic and give you an antibiotic cream to apply.  Do not use peroxide on cats unless directed to do so by a vet.  It reacts with the flesh in cats and causes heat and irritation and slows healing.