Periodically my lower legs (between my ankles and knees) itch and burn to the point of driving me nuts.

There doesn't seem to be any consistency to the itching and burning. It can happen at any time of the year but it happens most of the time at night. I scratch my legs until they bleed. The more I scratch, the more they itch and burn. It does't seem to be caused by something I eat or after a shower. It just drives me nuts.