Dry skin often means itchy skin. Preventing the itch with routine moisturizing of the skin is the best treatment.
In the winter itchy skin is usually more of a problem. Cold air means low humidity, when heaters are turned on the air gets even drier. Your skin dries out too.
The skin has a natural barrier to reduce moisture loss. This barrier or shield is made up of a dead layer of skin cells mixed with lipids or fats. This barrier cannot always withstand the repeat soap and water exposure. Harsh detergent soaps are the worst because they strip the fats away. If you use washcloths and other scrubbing pads you may be doing more harm than good.
Decrease your shower/bath time to about 5 to 10 minutes. Decrease soap use and limit your lather to the pits, groin and face. Soaps that are well known for being gentle include: Dove, Caress, Oil of Olay, Aveeno, and Cetaphil (not Ivory!!).
When you get out of the shower, before drying off, try rubbing a thin film of petroleum jelly into the wet skin, then pat (not rub) dry with a towel. It takes some trial and error but this is a wonderful way to lock moisture back into your skin and the jelly creates a barrier over your skin.