What Causes Itchy Rashes On The Hip?

I have a rash that has appeared on both sides of my hips. The rash is extremely itchy. I notice it itches a lot when my body tends to heat up. The more I scratch the more it spreads. I have been treating it with anti fungal cream for about a week now. The itching tends to be less but still no significant improvement from healing. I originally had a dark patch on my pubic area and a lot of itching until I switched soaps and it appeared to spread to my hips. I have no visual sign of a ring worm. I notice after a lot of scratching I appear to have a line of dark bite looking marks. Any help is appreciated.