I have a rash for over 2 years now.

I have had a rash for a little over two years now, since August 2007 and it never went away.The rash is on my inner arm (the opposite side of my elbow). My rash has been itching for over two years now and there is never a day that goes by when my rash doesn't itch. The rash has a lot of little bumps surrounding it and when my rash gets dry the little bumps turn white. By the way, the rash appeared a couple of days after I was exposed to the sun. What could this rash be? Could it be serious? Please help me.