When the skin loses moisture, it often chaps and cracks, thus reducing the skins barrier properties. An additional symptom that occurs is winter itch. Winter itch often induces scratching, which weakens the skin's defense mechanism further.
Treatment is quite simple, or so it seams.
The primary differences between a lotion, cream, and ointment are the spreadability, elegance, and occlusiveness. Moisturizers work by occluding the skin to help dry damaged skin retain moisture thus allowing skin to heal and soften. Petrolatum and mineral oil are excellent occlusive agents and very effective at moisturizing skin. In a pure form they lack elegance but when combined with other ingredients correctly, they provide the desired lubrication and occlusion while minimizing the greasy feeling. When your skin is severely dry, damaged, and sensitive, a specially formulated moisturizer is needed.