What Causes Itchy Rashes On The Upper Thighs?

Hello,I am 37 years old and I have been having this rash for a couple of years now
its on both of my upper thighs and its on my waist and on my hops and it really is bothersome. My Dr was giving my some kind of steroid shots but it did not help and it eaves a bad dark scars where the rash is
it itches and hurts. They said it was not the shingles so I was hoping someone could help me out.