A pressure ulcer, sometimes called a "bed sore," is a skin injury that occurs in about 40,000 people every year. Usually, pressure sores happen when people are very ill for a long period of time and are not able to change their position in a bed or a chair. People who have conditions such as dementia and spend a lot of time in a bed or a chair might not even realize that they need to change their position.

What Is a Pressure Ulcer ("Bed Sore")?

Pressure ulcers are caused by forces that block the flow of blood to the skin:

  • When too much pressure being exerted on the same area of the skin for too long, such as when someone lies in the same position all the time.
  • When "shearing" forces cause the skin to bunch up in one area, such as when a person stays in a reclining position too long in either a bed or a chair.

Pressure ulcers can happen to:

  • Newborns in incubators who are resting on lines or tubes.
  • People with spinal cord injuries who have lost sensation and don't feel uncomfortable sitting in the same position day after day—and therefore don't realize that their skin is being affected.
  • People who are bed bound and who are unable to change their position in bed.

Although pressure ulcers can develop anywhere on the body, they are more likely to occur on the buttocks of people who sit in a chair all day or in the heels, above the tailbone, and on the insides of the elbows of people who have to stay in bed all day.

Pressure ulcers can result from friction injuries to the skin when a person is being pulled across a surface, such as being pulled across a sheet when the bed is being made or being pulled out of a wheelchair.

Skin also can be injured by prolonged exposure to tape, urine, and feces, or it might be injured by tape removal. Although these injuries might look similar to a pressure ulcer, they often aren't. However, this kind of wound is more likely to become a pressure ulcer if the skin is exposed to too much or too little moisture, scrubbing, or temperatures that are too cool or too warm.

Signs and Symptoms

Many people with pressure ulcers don't know that they have one. Pressure ulcers might first be seen by a family member, a caregiver, or a physical therapist or other health care provider.

Pressure ulcers might be noticed when bathing or dressing someone who is at risk for developing them. A foul odor or the presence of yellow, brown, or gray mushy material on bedding or clothing might be noticed first and traced to an opening in the skin. Although pressure ulcers can be very painful, the person who has the ulcer might not notice any pain or might have pain but not be able to communicate it.

How Is It Diagnosed?

The physical therapist will conduct a full evaluation, including staging the pressure ulcer based on a system developed by the National Pressure Ulcer Advisory Panel (NPUAP):

  • Stage I ulcer - persistent reddening of the skin due to staying in the same position for too long. In darker skin, the skin might look purple. The skin might feel warmer to the touch than the surrounding skin.
  • Stage II ulcer - shallow wound that goes only partially into the skin, usually caused by friction.
  • Stage III ulcer - a deeper wound that goes through all of the layers of the skin, including fatty tissue under the skin.
  • Stage IV ulcer – a wound that goes deeper than just the skin, down into the muscle, tendon, ligament, or bone; it might even expose nerves and blood vessels.

These stages don't necessarily tell how severe a pressure ulcer is, and ulcers don't always progress from one stage to the next. What looks like a "simple" stage I ulcer might be a minor irritation of the skin—or might be hiding a large mass of injured tissue beneath.

If there are blood-filled blisters, or purple or maroon areas of what appears to be uninjured skin, that could mean the tissue beneath the uninjured-looking skin is dead. On the other hand, there might be extensive death of tissue such as muscle, but the skin might not look injured at all. This is why a large ulcer might seem to appear "out of nowhere" within a matter of a few days. Muscle and other tissue near bone may be damaged by pressure before the skin breaks down, revealing a large wound extending to the bone. Detailed examination by a physical therapist or other health care provider is needed.

Based on the examination, the physical therapist will decide whether any further testing or consultation with another health care provider is necessary. In some cases, surgery or the prescription of antibiotics by a physician may be necessary.