What Is The Treatment For White Patches In The Leg?

hi im 20 years old 5 ''4 and 10 stone, i have a history of eczema/ i have this white patch on my leg which has been there for a year now. It does not tan and is not iratable. however a few months ago i had a rash around the edge of the patch. I had a biopsy but they only found traces of eczema. It cleared up on it's own but the white patch hasnt. i now have dots of it forming on my other leg. im worried that its permenant what could it be