What Causes Red Blotches On My Upper Arms And Back?

I have red blotches on my upper arms and back. I have been trying to treat at the dermatoligist but have not seem to get very far.I have had this for over a year. If I use medication the redness appears to go away but I can still see that the marks are on my skin. I am currently using Hylatopic Plus but not getting any results. Any suggestion?