Dry skin (xeroderma)

[Renato]

Xeroderma is ordinary dry skin.
(See also Itching.)
Normal skin owes its soft, pliable texture to its water content. To help protect against water loss, the outer layer of skin contains oil, which slows evaporation and holds moisture in the deeper layers of skin. If the oil is depleted, the skin becomes dry. Dry skin, unless it is an inherited disorder or is caused by another condition, is called xeroderma.
Dry skin is common, especially among people past middle age. Risk factors for dry skin include

Cold, dry weather
Frequent bathing, particularly if using harsh soaps
Atopic dermatitis
Older age

Bathing washes away surface oils, allowing the skin to dry out. Dry skin may become irritated and often itches. Sometimes it sloughs off in small flakes and scales. Scaling most often affects the lower legs. Rubbing or scratching dry skin can lead to infection and scarring.