skin disorders
Pressure Sores
Causes of Pressure Sores
Causes that contribute to the development of pressure sores include Pressure Traction Friction Moisture Pressure on skin, especially when over or between bony areas, reduces or cuts off blood flow to the skin. Pressure can be caused by a bed, wheelchair, cast, splint, poorly fitting artificial (prosthetic) device, or other object. If blood flow is cut off for more than a few hours, the skin dies, beginning with its outer layer (epidermis). The dead skin breaks down and an open sore (ulcer) develops. Most people do not develop pressure sores because they constantly shift position without thinking, even when they are asleep. However, some people cannot move normally and are therefore at greater risk of developing pressure sores. They include people who are paralyzed, comatose, very weak, sedated, or restrained. People who are paralyzed or comatose are at particular risk because they also may be unable to move or feel pain (pain normally motivates people to move or to ask to be moved). Traction is a sideways pulling force on the skin. It also reduces blood flow to the skin. Traction occurs when, for example, people are placed on an incline (such as when they are made to sit up on an inclined bed) and their skin becomes stretched. Muscles and tissues under the top layer of skin are drawn down by gravity, but the top layers of skin remain in contact with the outer surface (such as bed linens). When the skin is stretched, the effect is much like pressure. Friction is the skin rubbing against clothing or bedding. It can lead to or worsen pressure sores. Repeated friction may wear away the top layers of skin. Such skin friction may occur, for example, if people are pulled repeatedly across a bed. Moisture can increase skin friction and weaken or damage the protective outer layer of skin if the skin is exposed to it for a long time. For example, the skin may be in prolonged contact with perspiration, urine (due to Urinary Incontinence in Adults ), or feces (due to 