Bed Sores & Pressure Ulcers: Prevention, and Treatment

Pressure ulcers, commonly referred to as bed sores, are areas of localised damage to the skin and underlying tissue caused by prolonged pressure and shear forces. These wounds typically develop over bony prominences or in areas of contact with medical devices.  

Pressure ulcers range in severity from non-blanchable erythema (redness) to deep wounds exposing muscle or bone, classified across six stages. Without proper prevention and management, they can lead to significant pain, infection, and complications, particularly in individuals with limited mobility. 

This guide explores the causes, prevention strategies, and treatment options. Helping healthcare professionals, caregivers, and organisations implement effective pressure care solutions. 

“A pressure ulcer is “Localised damage to the skin/and/or underlying tissue, usually over a bony prominence or relayed to a device, resulting from sustained pressure including pressure associated with shear. The lesion can present as intact skin or an open ulcer and may be painful.” – National Pressure Injury Advisory Panel, European Pressure Ulcer Advisory Panel and Pan Pacific Pressure Injury Alliance.

What’s the difference between bed sores and pressure ulcers?

No, there is no difference between bed sores & pressure ulcers. The terms bed sores and pressure ulcers refer to the same condition: localised damage to the skin and underlying tissue caused by prolonged pressure.  

While “pressure ulcer” is the clinically recognised term used by healthcare professionals, “bed sore” is the more commonly used term among patients, caregivers, and the general public. 

What causes pressure ulcers?

Pressure ulcers, also known as bed sores, develop when prolonged pressure restricts blood flow to the skin and underlying tissues. This lack of circulation deprives the tissue of oxygen and essential nutrients, leading to skin breakdown and ulcer formation. The primary causes of pressure ulcers include:

Sustained pressure 

Continuous pressure over a bony prominence (such as the sacrum, heels, or elbows) compresses soft tissue between the bone and an external surface, cutting off circulation and leading to tissue damage. 

Shear forces

Shear forces play a significant role in the development of pressure ulcers (bed sores). Shear occurs when gravity causes a patient’s body to slide downwards, while resistance from the bed or chair holds the skin in place. This results in the deeper tissues and bones shifting in one direction, while the skin and surface layers are pulled in another, essentially ‘dragging’ against the support surface. 

This internal shearing action can lead to torn capillaries, tissue death, and damage to blood vessels within the subcutaneous layers. When pressure and shear are combined this can lead to severe pressure damage.

These effects are most noticeable during postural changes, especially when the skin sticks to a surface with high friction. Preventing shear is essential in pressure ulcer prevention strategies, particularly in individuals with limited mobility or those who frequently require repositioning. 

Friction

Friction is another key factor in the formation of pressure ulcers. It occurs when two surfaces, such as skin and bedding, rub together, stripping away the superficial layers of the skin. This repeated movement can lead to the separation of the epidermis from the dermis, often resulting in painful blisters. 

The presence of moisture, such as sweat or incontinence, makes the skin more vulnerable to friction damage. Friction-related injuries are frequently associated with poor manual handling techniques or repetitive movements, especially during repositioning. While friction alone may not cause pressure ulcers, it significantly increases the likelihood of shearing due to the resistance it creates. Which in turn can lead to pressure ulcer development. 

Moisture

Excess moisture from sweat, incontinence, or wound fluid can weaken the skin barrier, increasing the risk of skin breakdown. 

Most common locations for pressure damage

Sacrum – lower back, very close to the skin surface; no muscle coverage on some areas. 

Heel area – the Achilles tendon is just beneath a thin layer of subcutaneous fat superior to the heel. 

Elbows – the bone is very close to the skin surface; no muscle present beneath the skin. 

Ankle area -the lateral malleolus is covered in a thin layer of ligament, with a thin layer of muscle over the top of the ligament. 

Who is at risk of pressure ulcers?

Certain individuals are more vulnerable due to prolonged pressure, shear forces, or underlying health conditions. Identifying at-risk individuals early is essential for prevention, enabling timely interventions such as specialist support surfaces, frequent repositioning, and skin care management. Those at the highest risk include: 

People with reduced mobility

Individuals who are bedbound, use wheelchairs, or have restricted movement are unable to reposition themselves frequently, leading to prolonged pressure on certain areas of the body. 

People with reduced sensation

Conditions such as spinal cord injuries (SCI), nerve damage, or diabetes can impair sensation, making it harder to detect early signs of pressure damage. 

Individuals using medical devices

Equipment such as oxygen masks, catheters, and braces can exert continuous pressure on the skin, increasing risk. 

People with poor circulation

Vascular conditions, diabetes, or heart disease can reduce blood flow, making it easier for pressure to compress the blood vessels leading to the development of pressure ulcers. 

Those affected by moisture or skin breakdown

Excessive sweating, incontinence, or wound fluid can weaken the skin, while dry, fragile skin can also increase vulnerability. 

People with malnutrition or dehydration

A lack of adequate nutrition, including protein, vitamins, and poor fluid intake can affect skin integrity, increasing the risk of pressure ulcer development and slower healing wounds.  

Elderly or frail individuals

As skin thins with age, it becomes more prone to damage, especially when combined with other risk factors such as immobility or poor circulation. 

How to identify pressure ulcers

Early identification is essential to prevent worsening tissue damage. They can develop quickly, especially in individuals at high risk, so regular skin assessments are critical. 

Key signs of pressure ulcers:

• Localised damage – pressure ulcers present as localised areas of skin damage, usually over bony prominence. Localised damage will present as specific areas of discoloured skin with clearly defined edges. 
• Changes in skin colour – affected areas may appear pink or red in lighter skin tones and blue, purple, maroon or darker in skin tone for dark skin. In light skin, discolouration that does not fade when pressure is applied over the area with your finger can indicate early tissue damage.
• Temperature differences – the skin may feel warmer or cooler than the surrounding area, which can indicate inflammation or reduced blood flow.
• Skin texture changes – the affected area might feel firm, soft, boggy (spongy), or swollen, suggesting underlying tissue damage.
• Pain or Discomfort – even if the skin appears intact, pressure ulcers can cause pain, itching, or tenderness, especially in early stages.
• Blisters or open wounds – As pressure ulcers progress, they may present as superficial wounds or as deeper wounds with extensive tissue loss depending on severity. Clear filled blisters can appear indicating the presence of friction. Blood filled blisters can indicate deeper tissue damage and may be categorised as suspected deep tissue injury (SDTI).

Assessing Skin for Early Signs

• Use good lighting – natural or bright lighting helps detect early colour changes, especially on darker skin tones. Moistening dark skin can enhance your visual assessment.
• Feel the skin – assess temperature and texture differences by gently pressing on suspected areas.
• Check high-risk areas – Most commonly develop over bony prominences such as heels, sacrum, hips, elbows, and shoulders.
• Monitor moisture levels – skin that is excessively moist or too dry is more prone to breakdown.

Why early identification matters

Detection at an early stage allows for immediate intervention, preventing progression to severe wounds that can lead to pain, infection, and long-term complications. Regular skin checks and prompt action are key to prevention and treatment.

Categories of pressure ulcer

Category 1

– Intact skin with non-blanching erythema (redness).
– Usually over a bony prominence.
– The area may be painful, firm, soft, warmer or cooler, compared to adjacent tissue.

Category 2

– Superficial skin loss or a blister without slough or bruising.
– Blister is usually from shearing or friction.
– Category 2 blister is full of clear fluid.
– Likely feels painful for the patient as the superficial skin loss exposes the nerve endings.

Category 3

– Full thickness skin loss.
– May have subcutaneous fat visible
– Often includes undermining or tunnelling.
– Bone, tendon and muscle would NOT be exposed.

Category 4

– Full thickness tissue loss.
– Bone, tendon, or muscle will be exposed or be palpable.
– Often includes undermining or tunnelling.
– Detrimental to patients, affecting their dignity and emotional wellbeing.

Unstageable

– Full thickness skin/tissue loss where the depth of the ulcer is completely obscured by slough and/or necrotic tissue.
– Cannot determine depth until this slough/necrotic tissue is removed.

Suspected Deep Tissue Injury

– Purple or maroon localised area of discoloured intact skin or blood-filled blister due to damage of underlying soft tissue from pressure and/or shear.
– DTIs have the potential to develop into large, deep wounds with significant tissue loss that have serious consequences for patients.
– Can be difficult to assess

Medical Device related pressure ulcers (MDRPU)

– Pressure ulcers that result from the use of devices designed and applied for diagnostic or therapeutic purposes.
– Whilst some MDRPU may also be allocated a category of damage, others may not as they are on parts of the anatomy that does not have the same structures as the skin – for example the mucosal membrane.