I suggest that you see a good internal medicine doctor for a complete evaluation. Itching is symptom for many diseases, and a complete physical exam with lab work is warranted. Good luck.
just an oponion,
i have itchy skin alot , mainly causes by either if im REALLY warm in my bed, i get itchy legs,
warm in heat outside, usely arms,
but i think its mainly dry skin. if this doesent relate, its best to check it at the doctors, if it sounds that abnormal :( hope it getts better soon! xx