Persistent dry and itching skin?

My skin is too much dry and itching. Due to this dryness my skin is wrinkled and cracked. If I scratch the place of itching changes its place. In that way I have to scratch my whole body. The dryness of the skin is also to the whole body. The dryness will increase during rainy and winter seasons. Applying moisturizers give temporary relief. Is there any dermatologist who can give a free online opinion why this skin condition occurs?