Suggest Remedy For Rash On Buttock Crack

I have a very irritated buttcrack. It extends from the very top to about 2 inches above the anus. It has been coming and going for a few months. It is painful. Usually I allow it to clear up on it's own but it becoming an annoyance. I tried to get a look at it in the mirror and it looks like a rash? Is this a yeast infection?