A pressure sore is a lesion that develops on the skin and underlying tissues, usually over bony areas, due to unrelieved pressure.

Pressure Sore (Skin Ulceration)
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Pressure sores result from lying or sitting in one position for too long a time.The skin and tissues need enough blood supply for oxygen and nutrients. Prolonged pressure cuts off the blood supply to tissues that are compressed between a bony area and a mattress, chair, or other object. Without oxygen and nutrients, the tissue starts to become damaged and die.

Several factors contribute to the development of pressure sores including:

  • Pressure—Pressure sores can result from the inability to change position or to feel discomfort caused by pressure. People with normal mobility and sensation change position automatically, without thinking.
  • Friction—Even friction from pulling someone across bed sheets can damage small blood vessels that supply the skin tissue.
  • Poor nutrition
  • Moisture—This can come from sweating due to fever or leakage of urine or stool.
  • Obesity —Extra weight increases pressure on the skin over the bones and joints.