How To Treat Raised Itchy Rashes On Buttocks?

I have a raise rash in my butt crack. It is not sore or itchy. Some years ago I had an auto immune rash under my arm which was red and raised. The skin specialist successfully treated it but told me to look out for a similar thing down below as it was a common place for it to occur. Could this be the same again quite a number of years later?