What are pressure ulcers and sores

Pressure sores, also known as pressure ulcers or bed sores, are lesions of the skin and tissue that can evolve into necrosis, affecting the epidermis, the dermis, and the subcutaneous layers, even reaching muscle and bone in more serious cases.

These ulcers develop mainly in areas of the body that are most subject to pressure during long periods in bed or in a seated position: the sacral region (the area where the buttocks join), the back of the head, and the heels.

Pressure sores can affect people of any age who are confined to be or a wheelchair, or who are unable to change position without assistance. However, they develop more frequently in the elderly, because the skin tends to be thinner and may heal more slowly. Pressure sores can be potentially fatal if not treated, or if pre-existing conditions hinder healing.

Causes of pressure sores

The risk factors for pressure sores include:

  • Age > 65
  • Reduced mobility (prolonged hospitalisation, bed rest, spinal cord injury, weakness)
  • Exposure to substances that may irritate the skin (urinary and/or faecal incontinence)
  • Reduced capacity for wounds to heal (malnutrition, diabetes, immobility, venous insufficiency).

The causes that contribute to the development of pressure sores are:

  • Compression of the skin, particularly over or between areas of bone, which reduces or interrupts cutaneous blood flow. If blood flow is interrupted for more than a few hours, the skin starts to die, beginning from the external layer (the epidermis). The dead skin breaks down, and an open wound develops (an ulcer). The majority of people do not develop pressure sores because they constantly change position without even thinking, even while sleeping. However, some individuals are unable to move normally, and therefore are more at risk of developing pressure sores.
  • A shear force applied to the skin reduces the flow of blood. For example, shear can occur when a person is on an inclined surface (for example seated on an inclined bed), and their skin is consequently pulled. The muscle and tissue beneath the surface layer are pushed downwards by gravity, while the surface of the skin remains in contact with the external surface (such as a sheet). This pulling of the skin has a very similar effect to pressure.
  • Friction (rubbing against clothes or bed linen) can cause or worsen pressure sores. Repeated friction can lead to surface layers of skin being removed. Such friction can be caused for example by the body being repeatedly pulled in order to be placed on a bed.
  • Humidity can increase friction on the skin and weaken on damage the external protective layer if the skin is exposed to humidity for an extended period of time. For example, the skin may be in prolonged contact with sweat or urine.
  • An insufficient diet increases the risk of developing pressure sores and slows down the healing process. Malnourished people may not have sufficient body fat to act as a cushion for tissue. Furthermore, in some cases the skin struggles to heal, in particular if there is a protein, vitamin or zinc deficiency.

Symptoms of pressure sores

The first sign of a pressure sore is reddening of the area of the skin, followed by a progressive deepening of the wound, involving the subcutaneous layer and full-depth muscle and adipose tissue, with the formation of areas of necrosis in more advanced stages. Wounds are subdivided into four grades, according to their level of development:

  • Grade 1: the skin is reddened or pink but is not broken. The lesion involves the epidermis only, which shows a permanent rash in the area concerned.
  • Grade 2: involvement of the epidermis and dermis. The pressure sore is not deep and is pink or red in colour. There is a certain loss of surface skin, with scratches, blisters or both.
  • Grade 3: the lesion is deeper, leading into the subcutaneous tissue and reaching but not involving the muscle layer. Visibly, the sore is a substantially deep ulcerated cavity and may involve the surrounding area, reaching deep-set levels.
  • Grade 4: the ulcerated area involves all tissue, skin is lost and the muscle, tendons and bones beneath are exposed.

Consequences of pressure sores

The onset of pressure sores is a complication deriving from the development of the pathology that caused the patient to be bed-ridden. Sores can easily become infected, with the risk of sepsis spreading, even reaching relatively distant organs.

Pressure sores that fail to heal can also lead to the formation of cellulitis and fistulas. Cellulitis is a bacterial infection that affects the skin and the tissue immediately beneath it. Fistulas are connections between the infected surface areas of the skin or wound and other structures, such as those deep inside the organism. For example, a fistula originating from a pressure sore near to the pelvis may connect to the intestine.

When wounds are particularly extensive, they issue large quantities of liquid, mineral salts and proteins, consequently weakening the sufferer and worsening their general conditions.

How to diagnose pressure sores

Diagnosis of pressure sores is a four-step process:


  1. Medical assessment
  2. Staging of the sore
  3. Assessment of nutritional status
  4. Blood tests and MRI scans for images


Doctors are capable of diagnosing pressure sores through physical examination, observing the appearance and location of the wounds. As it is difficult to establish the depth and seriousness of pressure sores, doctors or qualified health professionals establish the stage, and take photographs of the pressure sores in order to monitor their progression or healing.

People with pressure sores, particularly grade 3 or 4 sores, are usually subjected to blood tests. Examination is also made of the nutritional status of the patient, and in the event of malnutrition, further assessment is carried out.

How to prevent and treat pressure sores

Prevention is the best therapy against pressure sores. In the majority of cases, prevention is in the form of meticulous attention from all the people attending to the patient, such as nurses, assistants and family members.

Frequent repositioning is fundamental in avoiding pressure sores. People who are unable to move autonomously must be repositioned frequently. For example, bedridden people must change position every 1-2 hours at least. Those caring for the patient must carefully examine the skin in order to see any early signs of reddening or alteration of skin colour at least once a day.

Skin care is an essential factor in preventing pressure sores. The skin must be kept clean and dry, as moisture increases the risk of pressure sores. After washing, the skin needs to be delicately patted dry (avoiding any rubbing). The use of thick creams, which act as a barrier to protect the skin beneath from moisture, can help to prevent sores. With bedridden patients, sheets and clothes need to be changed frequently in order to make sure they are clean and dry.

The main aim of treatment is to reduce compression on sores, adequate cleaning and medication of wounds, monitoring of infection and suitable nourishment. Sometimes surgery is necessary in order to close large wounds.

Protein–energy malnutrition is considered a risk factor in the development of pressure sores and has a negative effect on their healing. Therefore, nutrition is an important aspect of a complete programme of therapy aimed at the prevention and treatment of pressure sores. A suitable calorie supply is fundamental in promoting the healing of tissue and guaranteeing proper use of proteins.


In the event that natural nutrition proves not to be sufficient in providing suitable levels of proteins and calories, it is necessary to contact one’s nutritionist, who will be able to recommend the most suitable treatment with oral nutritional supplements that are specifically suitable for the healing of pressure sores, guaranteeing that the correct levels of specific vitamins and minerals are provided.



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MAKLEBUST, JOANN. Pressure ulcers: etiology and prevention. The Nursing clinics of North America, 1987, 22.2: 359-377.
MERVIS, Joshua S.; PHILLIPS, Tania J. Pressure ulcers: Pathophysiology, epidemiology, risk factors, and presentation. Journal of the American Academy of Dermatology, 2019, 81.4: 881-890