What is a pressure sore?

What is a pressure sore?

Pressure ulcers are also commonly known as bed sores. They are injuries that occur when skin is subjected to pressure or friction, causing lack of blood supply to this area. They can range in severity from patches of discoloured skin to open wounds that expose the underlying bone or muscle.

How do pressure ulcers develop?

Pressure ulcers occur when a large amount of pressure is applied to an area of skin over a short period of time. However they can also occur when less pressure is applied over a prolonged period.

The skin has a rich blood supply that delivers oxygen to all its layers. Disrupting the blood supply as described above, can starve the skin of oxygen, resulting in local tissue damage and ulcer formation. The skin breaks down, allowing bacteria to penetrate and cause an infection. Pressure ulcers tend to affect people with health conditions that make it difficult to move, especially those confined to lying in a bed or sitting for prolonged periods of time.

Risk factors, as defined by the UK’s National Institute for Health and Care Excellence (NICE) can be found here:

Where are pressure ulcers most likely to occur?

Where are pressure ulcers most likely to occur?

Body parts that are most at risk of developing pressure ulcers are those that are not covered by a large amount of body fat and are in direct contact with a supporting surface, such as a bed or a wheelchair.

  • Knees, ankles, heels or toes

  • Spine

  • Tail bone

  • Shoulders or shoulder blades

  • Elbows

  • Back of your head

  • Rims of your ears

Wheelchair users are often at risk of developing pressure ulcers:

  • Buttocks

  • Backs of arms and legs

  • Back of the hip bone

How can the prevention of pressure ulcers be managed?

There are three key areas in which the prevention of pressure ulcers can be managed:

  • An efficient means of assessing the vulnerability of each patient
  • A choice of appropriate methods of treatment
  • Continuous monitoring of effectiveness
  • Rating scales can only provide a helpful guide because they may miss patients who subsequently develop sores and include some who don’t. Another problem is that patients are often only categorised on admission to hospital, although daily assessment is often necessary to ensure that a worsening risk is not overlooked. In the clinical situation, illness and pressure are the dominant factors.

Importance of choosing the right bed support

The choice of support system is vitally important in avoiding pressure ulcers. Mattress types fall broadly into two groups


Static support provided by conventional mattress produce sustained pressure. Varying grades of foam and construction will help to distribute weight, but it will not eliminate tissue distortion and ischaemia. The disadvantage of such systems is that the patient must be mobile or repositioned regularly to avoid the development of sores.


Rober’s mattress systems are dynamic, meaning they move. Dynamic alternating pressure systems have a generally wider application for high risk patients. However they could be considered for any situation in which a sustained period with little movement is likely. Most of Rober’s range consist of air mattresses of numerous different designs with cells that inflate and deflate reciprocally underneath the patient. In this way the weight bearing areas are constantly changing.

Rober mattresses work on either a 2 cell or 3 cell cycle. The 3-cell option offers maximum protection against pressure ulcers, but could be considered for the least mobile or larger patient. Rober offers a range of mattress solutions to cater for all patient’s needs. For guidance on which mattress to choose, use our handy product selector.

What types of pressure ulcers are there?

Healthcare professionals use several grading systems to describe the severity of pressure ulcers. The higher the grade, the more severe the injury to the skin and underlying tissue.

Grade 1

A grade one pressure ulcer is the most superficial type of ulcer. The affected area of skin appears discoloured – it is red in white people, and purple or blue in people with darker-coloured skin. Grade one pressure ulcers do not turn white when pressure is placed on them. The skin remains intact, but it may hurt or itch. It may also feel either warm and spongy, or hard.

Grade 2

In grade two pressure ulcers, some of the outer surface of the skin (the epidermis) or the deeper layer of skin (the dermis) is damaged, leading to skin loss. The ulcer looks like an open wound or a blister.

Grade 3

In grade three pressure ulcers, skin loss occurs throughout the entire thickness of the skin. The underlying tissue is also damaged, although the underlying muscle and bone are not. The ulcer appears as a deep, cavity-like wound.

Grade 4

A grade four pressure ulcer is the most severe type of pressure ulcer. The skin is severely damaged and the surrounding tissue begins to die (tissue necrosis). The underlying muscles or bone may also be damaged. People with grade four pressure ulcers have a high risk of developing a life-threatening infection.