Pressure Ulcers: Causes, Symptoms, Stages & Treatment

What Are Pressure Ulcers?

Pressure ulcers, commonly called bedsores or pressure sores, are localized injuries to the skin and underlying tissue resulting from prolonged pressure, typically over bony prominences. They develop when blood flow to an area is restricted, depriving cells of oxygen and nutrients, leading to tissue damage and death.

Pressure ulcers represent a significant healthcare challenge worldwide, affecting millions of people annually. These wounds occur when sustained pressure on the skin compresses the underlying blood vessels, reducing or completely blocking blood flow to the affected area. Without adequate blood supply, the cells in the skin and deeper tissues cannot receive the oxygen and nutrients they need to survive, leading to cellular death and tissue breakdown.

The severity of pressure ulcers ranges from mild redness of intact skin to deep wounds that expose muscle, tendon, or even bone. The damage often extends far beneath the visible surface, meaning that what appears to be a small wound may actually represent significant underlying tissue destruction. This is why pressure ulcers are sometimes described as similar to icebergs, with most of the damage hidden beneath the surface.

Understanding the mechanism of pressure ulcer formation is essential for both prevention and treatment. Three primary mechanical forces contribute to their development: pressure (perpendicular force against the skin), shear (when layers of tissue move in opposite directions), and friction (resistance when skin rubs against a surface). These forces, combined with individual risk factors, determine how quickly and severely a pressure ulcer develops.

Alternative Names for Pressure Ulcers

Pressure ulcers are known by several names in medical literature and everyday conversation. Understanding these terms can help when discussing the condition with healthcare providers or researching treatment options:

• Bedsores: The most common lay term, reflecting that these injuries often occur in bedridden patients
• Pressure sores: Another widely used term emphasizing the causative factor
• Decubitus ulcers: A medical term derived from Latin "decumbere" meaning "to lie down"
• Pressure injuries: The preferred term by the National Pressure Injury Advisory Panel (NPIAP), as it encompasses all stages including those without open wounds

What Causes Pressure Ulcers?

Pressure ulcers are caused by sustained pressure that restricts blood flow to the skin and underlying tissues. When tissues are deprived of oxygen and nutrients for prolonged periods, cells begin to die, resulting in tissue damage. Contributing factors include reduced mobility, poor nutrition, moisture exposure, and medical conditions affecting circulation or sensation.

The primary cause of pressure ulcers is mechanical loading on the skin that exceeds the capillary closure pressure, which is typically around 32 mmHg. When pressure exceeds this threshold for extended periods, blood flow to the affected area becomes compromised. The duration of pressure exposure is just as important as the intensity; lower pressures sustained over long periods can cause as much damage as higher pressures over shorter times.

The body naturally protects itself from pressure damage through a mechanism called shifting. Healthy individuals unconsciously adjust their position dozens of times per hour, even during sleep, redistributing pressure and allowing blood flow to recover in previously compressed areas. This protective mechanism fails in people who cannot move independently or who have impaired sensation and do not feel the discomfort that triggers repositioning.

Beyond pressure itself, several interacting factors influence pressure ulcer development. Shear forces occur when the body slides against a surface while the skin remains stationary, or vice versa, stretching and damaging blood vessels in the deeper tissues. This commonly happens when a patient slides down in bed or is pulled across sheets during repositioning. Friction damages the outer layer of skin when it rubs against surfaces, making the skin more vulnerable to pressure damage.

Risk Factors for Pressure Ulcer Development

Multiple factors increase an individual's susceptibility to pressure ulcers. Understanding these risk factors is crucial for identifying people who need preventive interventions:

• Immobility: Being bedridden, wheelchair-bound, or having limited ability to change position independently
• Reduced sensation: Conditions like spinal cord injury, stroke, or diabetic neuropathy that impair the ability to feel pressure discomfort
• Poor nutrition: Inadequate protein, calories, vitamins, and minerals impair skin integrity and healing ability
• Moisture: Incontinence, excessive sweating, or wound drainage weakens skin and increases friction
• Advanced age: Elderly skin is thinner, less elastic, and more vulnerable to damage
• Circulatory problems: Peripheral vascular disease, heart failure, and diabetes reduce blood flow to tissues
• Low body weight: Reduced fat and muscle padding over bony prominences increases pressure concentration
• Cognitive impairment: Dementia or altered consciousness reduces awareness of need to reposition

What Are the Symptoms of Pressure Ulcers?

Early symptoms of pressure ulcers include persistent redness that does not fade when pressed (non-blanchable erythema), skin that feels unusually warm or cool, areas of hardness or softness compared to surrounding skin, and pain or tenderness at pressure points. As ulcers progress, symptoms include blisters, open wounds, foul odor, and visible deep tissue damage.

Recognizing pressure ulcers early is critical for preventing progression to more severe stages. The earliest sign is typically a change in the appearance or texture of the skin over a bony prominence. In people with lighter skin, this appears as redness that persists for more than 30 minutes after pressure is relieved. Importantly, this redness does not temporarily disappear (blanch) when you press on it with your finger, distinguishing it from normal reactive redness.

In individuals with darker skin tones, the early signs of pressure damage may be more challenging to identify visually. Rather than redness, the affected area may appear purple, blue, or have a grayish discoloration. Healthcare providers and caregivers should pay attention to other indicators such as temperature changes (the area may feel warmer or cooler than surrounding skin), changes in tissue consistency (firmer or softer than adjacent areas), and reports of pain or itching from the patient.

As pressure ulcers progress beyond the initial stage, more obvious symptoms develop. The skin may develop blisters filled with clear or blood-tinged fluid, representing separation of the epidermis from deeper layers. Open wounds appear, initially shallow but potentially deepening to expose fat, muscle, tendon, or bone. Infected pressure ulcers produce additional symptoms including increased pain, expanding redness, warmth, swelling, purulent drainage, and foul odor.

Common Locations for Pressure Ulcers

Pressure ulcers develop most frequently over bony prominences where pressure concentrates during lying or sitting. The specific locations vary based on position:

What Are the 4 Stages of Pressure Ulcers?

Pressure ulcers are classified into four stages based on tissue damage depth: Stage 1 shows non-blanchable redness on intact skin; Stage 2 involves partial-thickness skin loss with a shallow open ulcer; Stage 3 features full-thickness skin loss with visible fat; Stage 4 involves full-thickness tissue loss with exposed bone, tendon, or muscle. Additional categories include unstageable ulcers and suspected deep tissue injuries.

The staging system for pressure ulcers, developed by the National Pressure Injury Advisory Panel (NPIAP), provides a standardized way to describe wound severity and guide treatment decisions. Understanding these stages helps patients, caregivers, and healthcare providers communicate effectively about wound status and healing progress.

It is important to understand that staging describes the maximum depth of tissue damage visible at the time of assessment. Pressure ulcers do not heal in reverse stage order; a Stage 4 ulcer does not become a Stage 3 as it improves. Instead, the wound gradually fills with new tissue (granulation) and eventually closes. Healthcare providers document healing progress using measurements and descriptions of wound characteristics rather than reverse staging.

Stage 1: Non-Blanchable Erythema

Stage 1 pressure ulcers represent the earliest identifiable stage of pressure damage. The skin remains intact, but there is visible redness (in lighter skin) or discoloration (in darker skin) that does not fade when pressed. This non-blanchable erythema indicates that microcirculation damage has occurred in the underlying tissue.

Additional features of Stage 1 ulcers may include temperature differences (the area may feel warmer or cooler than surrounding tissue), changes in tissue consistency (firmer or softer), and patient reports of pain, burning, or itching. At this stage, the damage is potentially reversible with prompt intervention including pressure relief, positioning changes, and skin protection.

Stage 2: Partial-Thickness Skin Loss

Stage 2 pressure ulcers involve damage to the epidermis and possibly the dermis, presenting as a shallow open ulcer with a red-pink wound bed. These wounds may also appear as intact or ruptured fluid-filled blisters. The wound bed should not contain dead tissue (slough or eschar) at this stage.

Stage 2 ulcers are typically painful and may produce moderate amounts of clear to slightly blood-tinged drainage. With appropriate care including pressure relief, moisture management, and proper wound dressings, Stage 2 ulcers generally heal within several weeks without significant scarring.

Stage 3: Full-Thickness Skin Loss

Stage 3 pressure ulcers involve complete loss of skin thickness with visible subcutaneous fat. Bone, tendon, and muscle are not visible or directly palpable, though slough or eschar may be present. The wound may include undermining (tissue destruction extending under the wound edges) and tunneling (narrow channels extending from the wound).

The depth of Stage 3 ulcers varies by anatomical location. Areas with significant subcutaneous tissue (such as the buttocks) may develop very deep Stage 3 wounds, while ulcers on areas with minimal subcutaneous fat (such as the ear or ankle) may appear relatively shallow despite being Stage 3.

Stage 4: Full-Thickness Tissue Loss

Stage 4 pressure ulcers represent the most severe classification, involving full-thickness tissue loss with exposed or directly palpable bone, tendon, cartilage, or muscle. These wounds often include extensive undermining, tunneling, and may be covered with slough or eschar. The risk of serious complications including osteomyelitis (bone infection) and sepsis is significant.

Stage 4 ulcers require intensive treatment often including surgical intervention, long-term wound care, and management of underlying risk factors. Healing takes months to years and may ultimately require surgical closure procedures such as flap surgery.

When Should You Seek Medical Care?

Seek medical care if you notice any signs of a pressure ulcer developing, especially persistent redness over bony areas that does not fade when pressed. Seek urgent care for signs of infection including increased redness, warmth, swelling, pus, foul odor, or fever. Stage 3 and 4 pressure ulcers require professional wound care management.

Early medical intervention significantly improves outcomes for pressure ulcers. If you or someone you care for has limited mobility and you notice changes in the skin over pressure points, it is important to have a healthcare provider assess the situation promptly. What appears to be a minor skin problem can represent significant underlying tissue damage that requires professional evaluation and treatment.

Primary care providers, home health nurses, wound care specialists, and dermatologists can all assess and manage pressure ulcers. The appropriate level of care depends on the ulcer's severity and the patient's overall health status. Many Stage 1 and 2 ulcers can be managed effectively with guidance from primary care, while more advanced wounds may require specialized wound care clinics.

How Can Pressure Ulcers Be Prevented?

Pressure ulcers are prevented through regular repositioning every 2 hours when in bed and every 15-30 minutes when sitting, using pressure-redistributing mattresses and cushions, keeping skin clean and moisturized, maintaining adequate nutrition, managing moisture from incontinence, and performing daily skin inspections over bony prominences.

Prevention is far more effective than treatment for pressure ulcers. Once a pressure ulcer develops, healing can take weeks to months for minor wounds and months to years for severe ones. By implementing consistent preventive measures, the vast majority of pressure ulcers can be avoided, even in high-risk individuals.

The cornerstone of pressure ulcer prevention is frequent repositioning to relieve pressure on vulnerable areas. For individuals who are bedridden, this means turning at least every two hours, alternating between back, left side, and right side positions. Using the 30-degree lateral tilt position rather than lying directly on the side helps avoid direct pressure on the hip bone. Pillows or foam wedges positioned between the knees and ankles prevent direct contact between bony prominences.

For individuals who use wheelchairs, weight shifts should occur every 15 to 30 minutes. This can be accomplished by leaning forward, leaning to each side, or having a caregiver assist with lifting. Power wheelchair users may benefit from tilt-in-space features that allow position changes without leaving the chair.

Pressure-Redistributing Surfaces

Specialized mattresses, overlays, and cushions play an important role in pressure ulcer prevention. These devices work by distributing body weight over a larger surface area, reducing the pressure at any single point. Options range from simple foam overlays to sophisticated alternating pressure air mattresses that automatically cycle between high and low pressure zones.

The choice of support surface depends on the individual's risk level and existing skin condition. Healthcare providers and equipment specialists can help determine the most appropriate option. It is important to understand that pressure-redistributing surfaces complement but do not replace regular repositioning.

Skin Care and Hygiene

Maintaining healthy skin improves its resilience to pressure damage. Key skin care practices include:

• Keep skin clean: Wash with mild soap and warm water, avoiding hot water that can dry the skin
• Keep skin moisturized: Apply moisturizing cream or lotion to keep skin supple, especially over bony areas
• Manage moisture: Keep skin dry by promptly changing wet clothing or incontinence products, using barrier creams to protect from moisture
• Avoid friction: Lift rather than drag when repositioning, use transfer boards and lift sheets, keep bed linens smooth
• Inspect skin daily: Check all pressure points carefully, using a mirror or asking for help to see areas you cannot easily view

Nutrition for Skin Health

Adequate nutrition is essential for maintaining skin integrity and supporting healing if wounds develop. Key nutritional considerations include:

• Protein: Crucial for skin repair and immune function; aim for adequate high-quality protein sources
• Calories: Sufficient energy intake prevents the body from breaking down muscle for fuel
• Vitamin C: Essential for collagen synthesis and wound healing
• Zinc: Supports immune function and tissue repair
• Hydration: Adequate fluid intake keeps skin hydrated and supple

Individuals at risk for pressure ulcers may benefit from nutritional assessment and supplementation. Registered dietitians can help develop appropriate nutrition plans for those with existing pressure ulcers or elevated risk.

How Are Pressure Ulcers Treated?

Pressure ulcer treatment involves relieving pressure on the affected area, proper wound care including cleaning and appropriate dressings, debridement of dead tissue when needed, managing infection, optimizing nutrition, and addressing underlying risk factors. Advanced treatments for severe wounds include negative pressure wound therapy and surgical interventions.

Effective pressure ulcer treatment requires a comprehensive approach that addresses both the wound itself and the factors that contributed to its development. Without correcting underlying causes such as continued pressure, poor nutrition, or moisture exposure, wounds will not heal despite local wound care interventions.

The first priority in treating any pressure ulcer is complete pressure relief on the affected area. This means the patient should not lie or sit on the wound at all during healing. For sacral or buttock wounds, this often requires significant changes to positioning schedules and may involve specialized beds that can reposition patients automatically.

Wound Care Principles

Local wound care for pressure ulcers follows principles designed to support the natural healing process:

• Cleansing: Wounds should be gently cleaned with normal saline or appropriate wound cleaners to remove debris and bacteria without damaging healing tissue
• Debridement: Dead tissue (slough and eschar) must be removed as it delays healing and provides a medium for bacterial growth. Methods include sharp debridement, enzymatic agents, autolytic dressings, or biosurgery (medical maggots)
• Moist wound healing: Wounds heal faster in a moist environment. Modern dressings maintain appropriate moisture levels while absorbing excess drainage
• Protection: Dressings protect wounds from contamination and further trauma while allowing healing to progress

Types of Wound Dressings

The appropriate dressing for a pressure ulcer depends on wound characteristics including depth, drainage amount, presence of infection, and wound bed condition. Common dressing categories include:

• Film dressings: Thin, transparent adhesive sheets that protect Stage 1 ulcers and shallow Stage 2 wounds
• Hydrocolloids: Self-adhesive dressings that maintain moisture and promote autolytic debridement
• Foam dressings: Absorbent dressings for wounds with moderate to heavy drainage
• Alginates: Highly absorbent dressings derived from seaweed, suitable for heavily draining wounds
• Hydrogels: Moisture-donating dressings that hydrate dry wounds and support autolytic debridement
• Antimicrobial dressings: Dressings containing silver, iodine, or other agents for infected or at-risk wounds

Advanced Treatment Options

Severe or non-healing pressure ulcers may require advanced interventions:

• Negative pressure wound therapy (NPWT): Also called vacuum-assisted closure, this technique applies controlled suction to the wound, promoting granulation tissue formation and wound contraction
• Electrical stimulation: Low-level electrical current may stimulate cellular activity and promote healing
• Hyperbaric oxygen therapy: Breathing pure oxygen in a pressurized chamber increases oxygen delivery to tissues and may support healing in some cases
• Surgical closure: Large or chronic wounds may require surgical procedures including skin grafts or flap surgery to achieve closure

Managing Infection

Infected pressure ulcers require additional treatment beyond standard wound care. Signs of wound infection include increasing pain, expanding redness, warmth, swelling, purulent drainage, and foul odor. Systemic infection may cause fever, elevated white blood cell count, and general malaise.

Treatment for infected pressure ulcers includes topical antimicrobial agents, systemic antibiotics when indicated, increased frequency of wound care, and close monitoring for improvement. Deep infections involving bone (osteomyelitis) require prolonged antibiotic therapy and often surgical debridement.

What Are the Complications of Pressure Ulcers?

Pressure ulcer complications include local wound infection, cellulitis (spreading skin infection), osteomyelitis (bone infection), sepsis (life-threatening blood infection), and death. Additional complications include prolonged hospitalization, significant pain, reduced quality of life, and substantial healthcare costs.

Pressure ulcers can lead to serious and potentially life-threatening complications, particularly when not identified and treated promptly. Understanding these risks emphasizes the importance of prevention and early intervention.

Infection is the most common complication of pressure ulcers. Open wounds provide an entry point for bacteria, and the devitalized tissue in pressure ulcers creates an ideal environment for bacterial growth. Local wound infections can spread to surrounding skin (cellulitis), underlying bone (osteomyelitis), or the bloodstream (sepsis). Sepsis from pressure ulcer infection is a leading cause of death in patients with these wounds.

Pain significantly impacts quality of life for individuals with pressure ulcers. While some deep ulcers may have reduced sensation due to nerve damage, many pressure ulcers cause substantial pain that interferes with sleep, mobility, and daily activities. Pain management is an important component of comprehensive pressure ulcer care.

Prolonged healing and associated complications create significant burdens on patients, families, and healthcare systems. Advanced pressure ulcers may take months to years to heal, requiring ongoing wound care, multiple healthcare visits, and potentially surgical interventions. The financial cost of pressure ulcer care is substantial, with estimates in the billions of dollars annually in developed countries.