When does it itch? How bad is the itch? Like is it a mild itch or is it like stabbing, almost painful itch? Does it burn, too? Does temperature affect it? Do you have any cracking or does the skin look abnormal in any way? When does it itch, all the time or only sometimes?
How long has it been going on? Do your feet smell? Do you change your socks every day, wash your feet, and change your shoes at least every few days?
Please answer and I or someone else will do our best to pinpoint your problem.