What Is a Pressure Sore?

A pressure sore, also called pressure ulcer, bed sore or decubitis ulcer is an injury that usually is caused by unrelieved pressure that damages the skin and underlying tissue. Pressure sores range from mild (minor skin reddening) to severe (deep craters extending to muscle and bone).

What Causes Them?

Unrelieved pressure on the skin squeezes tiny blood vessels that supply the skin with nutrients and oxygen. When skin is starved of nutrients and oxygen for too long, the tissue dies and a pressure sore forms. Skin reddening that disappears after pressure is removed is normal and not a pressure sore.

Pressure sores are a serious problem that can lead to pain, a longer stay in the hospital or nursing home, and slower recovery from health problems. Anyone who must stay in a bed, chair or wheelchair because of illness or injury can get pressure sores. Fortunately, most pressure sores can be prevented, and when they do form, they do not have to get worse.

Where Do Pressure Sores Form?

Pressure sores form where bones cause the greatest force on the skin and tissue and squeezes them against an outside surface. This may be where bony parts of the body press against other body parts, mattress, or chair. In persons who must stay in bed, most pressure sores form on the lower back below the waist (sacrum), the hip bone (trochanter), and on the heels on people who are in chairs or wheelchairs. The exact spot where pressure sores form on people who are in chairs or wheelchairs depends on the sitting position. Pressure sores can form on the knees, ankles, and shoulder blades, back of head and spine. Braces (or orthoses) also can cause pressure sores if they rub too much in one place.

What things increase the chances of developing pressure sores?

  • Bed or chair confinement
  • Inability to move
  • Loss of bowel or bladder control (moisture may irritate the skin)
  • Poor nutrition (without a balanced diet, skin is not properly nourished)
  • Lowered mental awareness (inability of person to actively prevent pressure sores)

Taking Care of the Skin

Goal: To find and correct problems before pressure sores develop.

  • Inspect skin at least twice a day—in the morning and at night.
  • Check creases in the skin that can be irritated by clothing, braces, appliances, moisture or allergic reactions.
  • Check areas that remain reddened after position is changed and pressure has been relieved. Use a mirror to inspect areas that are hard to see.
  • Change position often (at least every two hours).
  • If skin shows no sign of redness, gradually increase the length of time between position changes.
  • If feet are properly positioned, lie on the stomach all night. Lying on the stomach will straighten hips, reduce leg spasms and relieve all pressure on the buttocks.
  • If you’re in a wheelchair, shift position at least every 15 to 30 minutes.

Protecting Skin From Injury

Prevention is the best treatment for pressure sores.

  • Avoid massage of skin over bony parts of the body.
  • If in bed, change position at least every two hours.
  • If in a chair, change position at least every hour. (If able, shift weight every 15 minutes while sitting.)
  • Reduce friction (rubbing) by lifting rather than dragging during repositioning and transfer.

This information is for educational purposes only. It is not intended to replace the advice of your health care providers. If you have any questions, talk with your doctor or others on your health care team.