if you just noticed it then up her temps....her air temp should go up about 10 degrees and drop the humidity to 40-50,the temp should make her ammune system kick in.....if you just caught it you might get lucky and it can go away on its own.

If it doesnt stop after 2-3 days of doing that you will have to take her to the vet. And even if it does stop you might want to just get her looked at anyways, and if everything is well at least it will save you the cost of the antiboitics and you will only pay the vet fee.

Good luck