Sore on Skin or Pressure Sores

Skin | Dermatology | Sore on Skin or Pressure Sores (Symptom)


A sore or pressure on the skin occurs when the blood supply to an area of the body ceases, dying the skin in that area. A person who has been confined to bed or that is always in a wheelchair puts pressure on the same parts of the body for long. This reduces blood flow to these parts, making them more likely to develop open wounds. The latter condition worsens when the patient touches the body against the sheets or is raised abruptly from the bed or chair.


Pressure sores are caused by pressure against the skin that inhibits an adequate supply of blood to skin and underlying tissues. Other factors related to limited mobility can make the skin vulnerable to damage and contribute to the development of pressure sores. There are three primary contributing factors:

(1) Sustained pressure ( when the skin and the underlying tissues are trapped between bone and a surface such as a wheelchair or bed, the pressure may be greater than the pressure of the blood flowing in the tiny vessels (capillaries) that deliver oxygen and other nutrients to tissues);

(2) Friction is the resistance to motion (when a person changes position or is handled by care providers, friction may occur when the skin is dragged across a surface. The resistance to motion may be even greater if the skin is moist);

(3) Shear occurs when two surfaces move in the opposite direction. For example, when a hospital bed is elevated at the head, a person can slide down in bed. As the tailbone moves down, the skin over the bone may stay in place — essentially pulling in the opposite direction.