I am 70 year old male, and have had a rash in the groin area, under the breast and in the armpit and down the arm about 6 inches, it is sometimes bright red, and gets lighter at times, but will not go away, I have had it for 10 years and two dermitologists have done two different biopsys and they come back as nothing wrong. nothing helps. I have psoriasis , and use betamethazone, on my legs but it does not help this other rash problem. STD s have been ruled out, who do I see about the problem.