Pressure Ulcers: Causes, Classification, Treatment, Risk Factors, Prevention and Complications

Also known as pressure sores, pressure injuries, bed sores and decubitus ulcers, are injuries or ischemic damage located in the skin and / or the underlying tissue.

Ulcers occur on the sacrum, coccyx, trochanter and heel.

Where are they produced?

The most common pressure pain sites include the skin covering the sacrum, coccyx, heels, or hips, but other sites such as the elbows, knees, ankles, back of the shoulders, or the back of the skull may be affected


Pressure ulcers occur due to pressure applied to the soft tissue that results in a total or partially blocked blood flow to the soft tissue.

Cutting is also a cause, since it can pull blood vessels that feed the skin. Pressure ulcers develop more frequently in individuals who are not moving, such as those who are bedridden or confined to a wheelchair.

It is widely believed that other factors can influence the tolerance of the skin to pressure and shear, which increases the risk of developing pressure ulcers.

These factors are skin moisture caused by sweating or incontinence, diseases that reduce blood flow to the skin, such as arteriosclerosis, or diseases that reduce skin sensation, such as paralysis or neuropathy .

There are four mechanisms that contribute to the development of pressure ulcer:

External pressure : applied to an area of ​​the body, especially over bony prominences, can cause blockage of blood capillaries, depriving tissues of oxygen and nutrients.

This causes ischemia (deficiency of blood in a particular area), hypoxia (insufficient amount of oxygen available to the cells), edema, inflammation and finally, necrosis and formation of ulcers.

Friction : is harmful to superficial blood vessels directly under the skin. It happens when two surfaces rub against each other. The skin on the elbows and can be damaged due to friction.

The back can also be injured when patients are pulled or slid on the bed sheets while being moved to bed or moved to a stretcher.

Shearing : it is a separation of the skin from the underlying tissues. When a patient sits partially on the bed, their skin may adhere to the sheet, making it susceptible to cutting.

This may also be possible in a patient who slides down while sitting in a chair.

Moisture : It is also a common culprit, sweat, urine, feces or excessive drainage of the wound can further aggravate the damage caused by pressure, friction and shear.

Classification of pressure ulcers

The definitions of the four stages of pressure ulcer are reviewed periodically, in summary, they are the following:

Stage 1 : intact skin with redness in an area usually located on a bony prominence. Dark skin may have no visible lesion; its color may differ from the adjacent area.

The area differs in characteristics such as thickness and temperature compared to adjacent tissue. Stage 1 may be difficult to detect in people with dark skin tones.

Stage 2 : Partial thickness loss of the dermis that appears as a shallow open ulcer with a pink-red bed, without dirt. It can also present as a blister filled with intact or open / broken serum.

It presents as a shiny or dry superficial ulcer without grime or bruises. This stage should not be used to describe skin tears, tape burns, perineal dermatitis, maceration or excoriation.

Stage 3 : loss of tissue of full thickness. Subcutaneous fat may be visible but bone, tendon or muscle are not exposed. Skin loss may be present but does not obscure the depth of tissue loss.

The depth of a pressure ulcer in stage 3 varies according to the anatomical location. The bridge of the nose, ear, occiput and malleolus have no adipose tissue (subcutaneous) and the ulcers of stage 3 may be superficial.

Conversely, areas of significant adiposity may develop extremely deep pressure ulcers in stage 3. The bone / tendon is not visible or directly palpable.

Stage 4: loss of full-thickness tissue with exposed bone, tendon or muscle. There may be eschar or eschar in some parts of the wound bed. They often include scour and tunneling.

The depth of a pressure ulcer in stage 4 varies according to the anatomical location. The bridge of the nose, ear, occiput and malleolus has no adipose tissue (subcutaneous) and these ulcers can be superficial.

The ulcers of Stage 4 may extend into muscle and / or support structures (eg, fascia, tendon or joint capsule), which makes osteomyelitis likely to occur. The exposed bone / tendon is visible or directly palpable.

Unstable : loss of tissue of full thickness in which the actual depth of the ulcer is completely obscured by mucus (yellow, brown, gray, green or brown) and / or eschar (tan, brown or black) in the bed of the wound.

Until enough slough and / or eschar is removed to expose the base of the wound, the true depth and, therefore, the stage can not be determined. Stable eschar (dry, intact, without erythema) on the heels is usually protective and should not be removed.

Suspected deep tissue injury : a localized purple or brown area of ​​discolored intact skin or blister filled with blood due to underlying soft tissue damage due to pressure and / or shear.

The area may be preceded by a tissue that is painful, firm, soft, swampy, warmer or cooler than the adjacent tissue. A deep tissue injury can be difficult to detect in people with dark skin tones.

The evolution may include a thin blister on a dark bed of the wound. The wound can evolve further and be covered by a thin eschar. The evolution can be a rapid exposure of additional layers of tissue even with optimal treatment.

When to see a Doctor

If you notice signs of an eschar, change your position to relieve pressure in the area. If you do not see an improvement in 24 to 48 hours, contact your doctor.

Seek immediate medical attention if you show signs of infection, such as fever, discharge from a sore, a sore that smells bad, or increased redness, warmth, or swelling around a sore.

Pressure sores treatment

The treatment of pressure ulcers may be slowed by the person’s age, medical conditions (such as arteriosclerosis, diabetes or infection), smoking or medications such as anti-inflammatories.

Biofilm is one of the most common reasons for delayed healing in pressure ulcers, occurs rapidly in wounds and stops healing by keeping the wound inflamed.

The elimination of frequent dead tissue and antimicrobial dressings is necessary to control the biofilm. Signs of pressure ulcer infection include slow or delayed healing and pale granulation tissue.

Signs and symptoms of systemic infection include fever, pain, redness, swelling, area heat, and purulent discharge. In addition, infected wounds may have gangrenous odor, discolor and eventually produce more pus.

To eliminate this problem, it is essential to apply antiseptics. Oxygenated water is not recommended for this task as it increases inflammation and prevents healing. It has been shown that iodine dressings penetrate bacterial biofilms.

Systemic antibiotics are not recommended in the treatment of local infection in a pressure ulcer, as it can cause bacterial resistance. They are only recommended if there is evidence of cellulitis, bone infection or bacteria in the blood.

Risk factors of pressure sores

There are more than 100 risk factors for pressure ulcers. Factors that can put a patient at risk include immobility, diabetes mellitus, peripheral vascular disease, malnutrition, stroke and hypotension.

Other factors are the age of 70 years and older, the current history of smoking, dry skin, low body mass index, urinary and fecal incontinence, physical restrictions, malignancy and history of pressure ulcers.

People are at risk of developing pressure ulcers if they have difficulty moving and can not change positions easily while sitting or in bed. Risk factors include:

Immobility : this could be due to poor health, spinal cord injuries and other causes.

Lack of sensory perception : Spinal cord injuries, neurological disorders, and other conditions can cause an inability to feel pain or discomfort, cause the warning signs and the need to change position to be ignored.

Poor nutrition and hydration : people need enough fluids, calories, proteins, vitamins and minerals in their daily diet to maintain healthy skin and prevent the breakdown of tissues.

Medical conditions that affect blood flow : health problems that can affect blood flow, such as diabetes and vascular diseases, increase the risk of tissue damage.


Although it is often prevented and treated if detected early.

Pressure ulcers can be very difficult to prevent in critically ill people, frail elderly and individuals with reduced mobility or in wheelchairs (especially when it comes to spinal injury).

Primary prevention is to redistribute the pressure by turning the person on a regular basis. The benefit of turning over to avoid more sores is well documented since at least the 19th century.

Redistributing pressure : the most important care for a person at risk for pressure ulcers and people with bedsores is the redistribution of pressure so that pressure is not applied to the ulcer.

Establish routine schedules to rotate and reposition patients, to avoid the development of pressure ulcers in those who are bedridden. The frequency of rotation and repositioning depends on the level of risk of the person.

Support surfaces : high density foam mattresses are 60% less likely to develop new pressure ulcers compared to normal foam mattresses.

Sheepskin coatings were also found on top of the mattresses to prevent the formation of new pressure ulcers. There is no clear research on the effectiveness of alternating pressure mattresses.

Redistributive pressure mattresses are used to reduce high pressure values ​​in the prominent or bony areas of the body. There are several important terms that are used to describe how these support surfaces work.

Many support surfaces redistribute the pressure by submerging and / or wrapping the body on the surface. Some support surfaces, including anti-cushion mattresses and cushions, contain multiple air chambers that are pumped alternately.

For people with paralysis, pressure displacement on a regular basis and the use of a wheelchair cushion with pressure relief components can help prevent pressure injuries.

Repositioning can often help prevent ulcers to avoid stress on the skin. Other strategies include quitting smoking, managing stress and exercising every day.

Tips for repositioning

Consider the following recommendations related to repositioning in a bed or chair:

Change your weight frequently : if you use a wheelchair, try to change your weight every 15 minutes. Ask for help to reposition once per hour.

Get up, if possible : if you have enough upper body strength, do push-ups in the wheelchair, lifting the body of the seat by pushing the arms of the chair.

Specialized wheelchair : some wheelchairs allow you to tilt them, which can relieve pressure.

Cushions or a pressure- relieving mattress: use cushions or a special mattress to relieve pressure and help ensure that your body is well positioned. Do not use donut cushions, as they can focus the pressure on the surrounding tissue.

Adjust the elevation of your bed : if your bed can rise on your head, raise it to no more than 30 degrees. This helps prevent shearing.

Controlling the heat and moisture levels of the skin surface, known as skin microclimate management, also plays an important role in the prevention and control of pressure ulcers.

Nutrition : In addition, adequate intake of protein and calories is important, it has been shown that vitamin C reduces the risk of pressure ulcers, maintaining adequate nutrition in newborns is also important to prevent pressure ulcers.

The use of supplements is recommended to maintain adequate levels of nutrition. Skin care is also important because damaged skin does not tolerate pressure.


Pressure ulcers can trigger other ailments, cause considerable suffering and can be expensive to treat. Some complications include:

Autonomic dysreflexia, distension of the bladder, bone infection, piarthrosis , sepsis, amyloidosis, anemia, urethral fistula, gangrene and very rarely malignant transformation (Marjolin’s ulcer – secondary carcinomas in chronic wounds).

Ulcers can recur if people do not follow the recommended treatment or may develop seromas, bruises, infections or wound dehiscence. People with paralysis are the most likely to have recurrent pressure sores.

In some cases, the complications of pressure ulcers can be life-threatening. The most common causes of death are derived from renal failure and amyloidosis.

Pressure ulcers are also painful, with individuals of all ages and all stages of pressure ulcers reporting pain.

In addition to turning and repositioning the person in bed or in the wheelchair, it is very important to eat a balanced diet with adequate proteins and to keep the skin free from exposure to urine and feces.

Other complications of pressure ulcers, some of which are life-threatening, include:

  • Cellulite : cellulite is an infection of the skin and soft tissues connected. It can cause heat, redness and swelling of the affected area. People with nerve damage often do not feel pain in the area affected by cellulite.
  • Bone and joint infections: joint infections (septic arthritis) can damage cartilage and tissue. Bone infections (osteomyelitis) can reduce the function of the joints and extremities.
  • Cancer : long-term wounds that do not heal (Marjolin ulcers) can become a type of squamous cell carcinoma
  • Septicemia : Rarely, a skin ulcer causes sepsis.


Pressure ulcers are areas of damaged skin caused by staying in one position for a long time. They are commonly formed where the bones are close to the skin, such as the ankles, back, elbows, heels and hips.

You are at risk if you are bedridden, use a wheelchair or can not change your position. Pressure ulcers can cause serious infections, some of which are life-threatening. They can be a problem for people in nursing homes.

You can prevent sores by keeping the skin clean and dry, changing positions every two hours, using pillows and products that relieve pressure.

Pressure ulcers have a variety of treatments, while advanced ulcers are slow to heal, so early treatment is best.