Suggest Treatment For Red Rashes On Scrotum

I have a red rash on my scrotum only. It does not itch and I had seen my GP twice now. He has prescibed a couple of different prescription fungal cremes which has made the redness better but does not eliminate it. My scrotum gets irritaded when I wear clothing and is fine at night. I have no sores or bumps. I have started on oral Lamisil for a few days now but have not seen a change yet.