25years Male Here , From Last 8months I Am Suffering

25years male here , from last 8months i am suffering from itching,when i rubbed the itching area it becomes reddiesh then after becoming black spot on that area.......nw my legs are very black....but total body is itching. how can i prevent from itching.........
i used
1) canditral 100mg
2)zimig cream
3)fluclox 150mg
but no use.............