I am not sure where you live but cold weather and itchy, dry skin is pretty common. I live in the Cleveland area and around this time of year, I could scratch my legs until they bleed. Have you tried lotions, oils or aloe to try and keep the area moist?
If you believe this is completly abnormal for you, call and make an appointment with your Dermatologist. I am sure they can help.
Good luck and keep us posted.