|
Dry skin is a common condition that can affect people of all ages, even infants. The medical term for dry skin is xerosis. Dry skin has a parched look, resulting from its inability to retain moisture, and usually feels "tight" and uncomfortable, especially right after cleansing.
Skin is composed of three layers: the epidermis, dermis and subcutaneous tissue. The outer protective layer of skin is the epidermis. The middle layer is the dermis, which contains blood vessels, glands and nerve endings. The bottom layer is the subcutaneous tissue, which contains fat, nerves and blood vessels.
Dry skin results from a lack of water in the stratum corneum, the outer, compacted layer of cells in the epidermis. Part of the stratum corneum between the cells is composed mainly of lipids (fats), such as cholesterol and fatty acids. These lipids form a strong, protective barrier that preserves moisture in the skin. A film of natural oil (sebum) excreted by glands in the subcutaneous tissue also helps retain moisture. When this protective barrier is stripped away, the skin cells lose water, which they need to stay healthy and supple. Scientists define dry skin based on measurable changes in water and lipids in the stratum corneum.
A healthy stratum corneum consists of about 30 percent water, which gives skin its resilience and elasticity. Most of the water is in the interior of the stratum corneum. In the outer layers, the amount of water depends on the environment. For instance, the drier the air, the drier the outermost layer of skin.
If a person experiences chronic or severe dry skin, they are advised to seek the care of a dermatologist. If dry skin is left untreated, it can lead to premature fine lines and wrinkles. Rarely, it may lead to more serious complications such as:
These complications usually occur when the skin’s normal protective layer is compromised, such as with excessive scratching and/or bleeding, which can provide a way for bacteria to invade the body. | 
/doctor_89.jpg "ulcerative colitis tips")