Pressure sores are areas of skin damage resulting from a lack of blood flow due to pressure.
Pressure sores can occur in people of any age who are bedridden, chairbound, or unable to reposition themselves. They occur where there is pressure on the skin from a bed, wheelchair, cast, splint, poorly fitting artificial (prosthetic) device, or other hard object. They tend to occur over or between bony areas where pressure on skin can be concentrated, such as over the hip bones, tailbone, heels, ankles, and elbows, but they can occur anywhere.
Pressure sores often develop in people after they have been hospitalized for a different problem. Pressure sores lengthen the time spent in hospitals or nursing homes. Pressure sores can be life threatening if they are untreated or if underlying health conditions prevent them from healing. Pressure sores are more common among older people. An estimated 1.3 to 3 million people in the United States have pressure sores, resulting in a significant financial burden to people and the health care system.
Causes that contribute to the development of pressure sores include
Pressure on skin, especially when over or between bony areas, reduces or cuts off blood flow to the skin. 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. Paralyzed and comatose people 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 (shearing forces) 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 (rubbing against clothing or bedding) 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, or feces.
Inadequate nutrition increases the risk of developing pressure sores and slows the healing process of sores that do develop. Undernourished people may not have enough body fat to cushion the tissue. Also, the skin heals poorly if people are undernourished, particularly if they are deficient in protein, vitamin C, or zinc.
For most people, pressure sores cause some pain and itching. However, in people whose senses are dulled, even severe sores may be painless.
Pressure sores are categorized according to the severity of soft-tissue damage.
Stage I: The skin is red or pink but is not broken. Darker-skinned people may not see changes in color. The sore may also be warmer, cooler, firmer, softer, or more tender than nearby skin. At this stage, an actual ulcer is not yet present.
Stage II: The pressure sore is shallow with a pink to red base. Some shallow skin loss, including abrasions, blisters, or both, occurs.
Stage III: The skin over the sore is worn away. The sore sometimes goes as deep as the layer of fat. Underlying muscles and bones are not exposed.
Stage IV: The skin is worn away and underlying muscles, tendons, and bones are exposed.
Unstageable: Sometimes doctors cannot determine what stage a pressure sore is. For example, pressure sores that are covered with debris or a thick, crusty surface (eschar) cannot be staged.
Suspected deep tissue injury: This newer category includes sores whose appearance suggests that underlying tissues may be damaged. Such damage may appear as purple to maroon areas of unbroken skin. The area may feel firmer, mushier, warmer, or cooler than surrounding tissue.
Pressure sores do not always progress from mild to severe stages. Sometimes the first noticeable sign is a stage III or IV sore.
If pressure sores become infected, they may have an unpleasant odor. Pus may be visible in or around the sore. Some people may have a fever. The area around the pressure sore may become red or feel warm, and pain may worsen if the infection spreads to the surrounding skin (causing cellulitis). Infection delays healing of shallow sores and can be life threatening in deeper sores. Infection can even penetrate the bone (osteomyelitis—see Osteomyelitis). In the most severe cases, infection can spread into the bloodstream (sepsis), causing fever or shaking chills.
Pressure sores that do not heal may also cause sinus tracts to form. Sinus tracts are passages that connect the infected area of the skin surface or the sore to other structures, such as those deep in the body. For example, a sinus tract from a pressure sore near the pelvis can connect to the bowel.
Doctors can usually diagnose pressure sores by doing a physical examination. Because the depth and severity of pressure sores are difficult to determine, doctors or specially trained health care practitioners stage and photograph pressure sores to monitor how they progress or heal. Doctors use specific criteria to determine how a pressure sore is healing.
Doctors also assess people for their nutrition status. People with pressure sores, especially those with stage III or IV sores, usually have blood tests. People who are undernourished are evaluated further.
When pressure sores do not heal, doctors often suspect a complication. If osteomyelitis is suspected, doctors do blood tests and often magnetic resonance imaging (MRI) or gadolinium-enhanced MRI. To confirm osteomyelitis, doctors may need to take a small sample (biopsy) of bone to see if bacteria grow from it (culture).
The prognosis for early-stage pressure sores is excellent if people have received timely, appropriate treatment, but healing typically requires weeks. After 6 months of treatment, more than 70% of stage II pressure sores, 50% of stage III pressure sores, and 30% of stage IV pressure sores resolve. Pressure sores often develop in people who are receiving care that is less than perfect. Without continual meticulous care, long-term prognosis is poor, even if pressure sores have healed.
Prevention is the best strategy for dealing with pressure sores. In most cases, pressure sores can be prevented by meticulous attention from all caregivers, including nurses, nurses' aides, and family members. Close daily inspection of a bedridden or chairbound person's skin can detect early redness or discoloration. Any sign of redness or discoloration at pressure areas is a signal that the person needs to be repositioned and kept from lying or sitting on the discolored area until it returns to normal.
Because shifting position is necessary to keep blood flowing to the skin, oversedation should be avoided and activity should be encouraged. People who cannot move themselves should be repositioned frequently. For example, people who are bedbound should be repositioned at least every 2 hours. The skin must be kept clean and dry because moisture increases the risk of developing pressure sores. Dry skin is less likely to stick to fabrics and cause friction or traction. After cleaning, the skin should be dried by gentle patting (avoiding rubbing the skin). The use of antifungal creams and creams that act as a barrier to moisture or skin-protective wipes may help prevent sores. For people confined to bed, sheets and clothing should be changed frequently to make sure they are clean and dry. Applying plain talc to skin in areas where two parts of the body press against each other (such as the buttocks and groin) can help keep the skin in these areas dry. Cornstarch may allow microorganisms to grow and should not be used.
Bony projections (such as heels and elbows) can be protected with soft materials, such as foam wedges and heel protectors. Protective padding, pillows, or sheepskin can be used to separate body surfaces. Special beds, mattresses, and seat cushions can reduce pressure and offer extra relief to people who are wheelchair-bound or bedridden. A doctor or nurse can recommend the most appropriate mattress surface or seat cushion. It is important to remember that none of these devices eliminate pressure completely or are a substitute for frequent repositioning.
Treating a pressure sore is much more difficult than preventing one. The main goals of treatment are to relieve pressure on the sores, clean and dress the sores appropriately, control infection, and provide adequate nutrition. Sometimes surgery is needed to close large sores.
To relieve pressure on the skin, people require careful positioning, protective devices, and support surfaces. In the earliest stage, pressure sores usually heal by themselves once pressure is removed.
Frequent repositioning (and selection of the proper position) is the main way to relieve pressure. Bedbound patients should be turned a minimum of every 2 hours and should be placed at an angle to the mattress when on their side to avoid direct pressure on the hips. Elevation of the head of the bed should be minimal to avoid the effects of traction. When people are being repositioned, to avoid unnecessary friction, lifting devices or bed linen should be used instead of dragging people. Doctors may instruct caregivers to follow a written schedule to direct and document repositioning. Chairbound people should be repositioned every hour and encouraged to change position on their own every 15 minutes.
Protective padding such as pillows, foam wedges, and heel protectors can be placed between the knees, ankles, and heels when people are lying on their back or on their side. Bony projections (such as heels and elbows) can be protected with soft materials such as foam wedges and heel protectors. Soft seat cushions are given to people who are able to sit in a chair.
Support surfaces, such as foam and other types of mattresses, under bedbound people can be changed to reduce pressure. Support surfaces are used in hospitals, nursing homes, and sometimes in private homes. Support surfaces are classified based on whether they require electricity to operate. Static surfaces do not require electricity, whereas dynamic surfaces do.
Static surfaces include air, foam, gel, and water overlays and mattresses. Egg-crate mattresses are not helpful for relieving pressure. In general, static surfaces increase the area over which weight is distributed, thus decreasing pressure and traction. Static surfaces have traditionally been used to prevent pressure sores or to treat stage I pressure sores.
Dynamic surfaces include alternating-air mattresses, low-air-loss mattresses, and air-fluidized mattresses. Alternating-air mattresses have air cells that are alternately inflated and deflated by a pump, which shifts supportive pressure from site to site. Low-air-loss mattresses are giant air-permeable pillows that are continuously inflated with air. The air flow has a drying effect on tissues. Air-fluidized mattresses circulate air. They reduce moisture and provide cooling. Dynamic surfaces are used if a pressure ulcer fails to heal when a static surface is used.
Wound cleaning and dressing:
To heal, pressure sores need to be cleaned, dead skin needs to be removed (a process called debridement), and dressings need to be applied.
The wound is cleaned when the dressing is changed. Health care practitioners often flood (irrigate) the sore, particularly its deep crevices, with saline to help loosen and clean away hidden debris.
A doctor may need to remove dead tissue with a scalpel, a chemical solution, a whirlpool bath, a special dressing, or biosurgery. Removal of dead tissue is usually painless, because pain is not felt in dead tissue. Some pain may be felt because healthy tissue is nearby.
Dressings are used to protect the sore and promote healing. Dressings are used for some stage I pressure sores and all others. When the skin is broken, a doctor or nurse considers the location and condition of the pressure sore when recommending a dressing. The amount of drainage oozing from the sores helps determine which type of dressing is best.
Pressures sores can cause significant pain. Doctors usually try to treat pain with acetaminophen or a nonsteroidal anti-inflammatory drug (NSAID) rather than with opioids. Opioids cause sedation and sedation causes immobility.
Most infections can be treated with antibiotics that are applied directly to the skin. Doctors also give antibiotics taken by mouth or vein if people have infection that has spread, for example, to the bloodstream, the skin beyond the sore, or the bone. Osteomyelitis is extremely difficult to cure and requires many weeks of treatment with an antibiotic.
Undernutrition is common among people with pressure sores. Adequate nutrition is important in helping pressure sores heal and in preventing new sores from forming. A well-balanced, high-protein diet is recommended. Also, if the person is found to be deficient in any vitamin, supplemental doses of that vitamin are recommended.
Deep or large pressure sores are difficult to treat. Sometimes they need to be closed with skin and muscle flaps (grafts). In these procedures, healthy, thicker tissue with a good blood supply is surgically repositioned to cover the damaged area. Skin flaps are useful for large, shallow pressure sores. Muscle flaps are used to close pressure sores over large bony areas (usually the base of the spine, hips, and the upper end of the thigh bones). Surgery is not always successful, however, especially for frail older people who are undernourished and have other disorders.
Last full review/revision June 2013 by Daniela Kroshinsky, MD, MPH; Lauren Strazzula, BA