A pressure ulcer, also called a pressure injury or pressure sore, is an area of localized damage to the skin and underlying tissue. It usually develops over a bony area when prolonged pressure, often combined with shear, reduces blood flow to the tissues.
Pressure ulcers are particularly common in people who have limited mobility or spend long periods in bed or in a chair. Without appropriate prevention and treatment, a small area of skin damage can progress into a deep wound involving muscle, tendon, or bone.
Understanding the stages, warning signs, risk factors, treatment options, and prevention strategies is important for patients, caregivers, nurses, and healthcare professionals.
What Is a Pressure Ulcer?
A pressure ulcer is an injury to the skin and underlying soft tissue caused primarily by intense or prolonged pressure, or pressure combined with shear. These injuries commonly occur over bony prominences such as the heels, hips, tailbone, elbows, ankles, and back of the head.
The term pressure injury is now widely used in healthcare. The National Pressure Ulcer Advisory Panel changed the terminology from “pressure ulcer” to “pressure injury” and updated the classification system.
The condition can range from persistent discoloration with intact skin to extensive tissue loss.
What Causes Pressure Ulcers?
The main cause is prolonged or excessive pressure on an area of the body.
Prolonged Pressure
When pressure remains on the same area for too long, blood vessels can become compressed. Reduced blood flow means that tissues receive less oxygen and nutrients.
If pressure continues, tissue damage can occur.
Shear
Shear happens when the skin stays relatively fixed while deeper tissues move in another direction. This can occur when a patient slides down in bed or when the head of a bed is raised.
Pressure and shear can work together to increase tissue damage.
Friction
Friction occurs when skin repeatedly rubs against clothing, bedding, or another surface. Although friction is not the same mechanism as pressure, it can damage the outer skin and increase vulnerability.
Moisture
Moisture from sweating, urine, stool, or wound drainage can weaken the skin barrier. This can make skin more susceptible to irritation and breakdown.
Common Locations of Pressure Ulcers
Pressure ulcers frequently develop over areas where bones are close to the skin.
Common locations include:
- Tailbone or sacrum
- Heels
- Hips
- Ankles
- Elbows
- Shoulder blades
- Back of the head
- Spine
- Knees
- Ears
The exact location depends on the person’s position and mobility.
For example, someone who spends most of the day in bed may be particularly vulnerable around the heels, sacrum, hips, and back of the head.
Who Is at Risk for Pressure Ulcers?
Anyone with reduced mobility can be at risk, but certain factors increase susceptibility.
Important risk factors include:
- Prolonged bed rest
- Wheelchair use
- Paralysis
- Reduced sensation
- Older age
- Poor nutritional status
- Dehydration
- Incontinence
- Limited ability to reposition
- Poor circulation
- Certain chronic illnesses
- Reduced consciousness
- Previous pressure injury
- Severe illness
A person’s overall health, mobility, nutrition, skin condition, and ability to communicate discomfort should all be considered when assessing pressure-injury risk.
Healthcare organizations can use standardized risk-assessment approaches alongside comprehensive skin assessments to identify people who need preventive interventions. AHRQ’s pressure-injury resources specifically emphasize risk assessment, skin assessment, care planning, and monitoring.
Stages of Pressure Ulcers
Pressure injuries are classified according to the depth and characteristics of tissue damage.
Stage 1 Pressure Injury
A Stage 1 pressure injury involves intact skin with a localized area of persistent non-blanchable redness, usually over a bony prominence.
The area may feel different from surrounding skin and may be warmer, cooler, firmer, softer, painful, or otherwise altered.
Stage 2 Pressure Injury
Stage 2 involves partial-thickness skin loss with exposed dermis.
The wound bed is generally pink or red and moist. It may also appear as an intact or ruptured serum-filled blister.
Stage 2 injuries do not expose deeper structures such as fat, muscle, tendon, or bone. Slough and eschar are not present in a Stage 2 injury.
Stage 3 Pressure Injury
A Stage 3 injury involves full-thickness skin loss.
Subcutaneous fat may be visible, and the wound may contain granulation tissue, slough, or eschar. Undermining and tunneling can occur.
Although the wound can be deep, exposed or directly palpable fascia, muscle, tendon, cartilage, or bone would indicate a more extensive injury rather than Stage 3.
Stage 4 Pressure Injury
Stage 4 is a severe pressure injury involving full-thickness skin and tissue loss.
Fascia, muscle, tendon, ligament, cartilage, or bone may be exposed or directly palpable.
These wounds can involve undermining, tunneling, slough, and eschar and require comprehensive medical and wound-care management.
Unstageable Pressure Injury
An unstageable pressure injury involves full-thickness skin and tissue loss, but the true depth cannot be determined because the wound is covered by slough or eschar.
Once the material obscuring the wound is appropriately removed, the underlying stage may become apparent.
Deep Tissue Pressure Injury
A deep tissue pressure injury may appear as persistent deep red, maroon, or purple discoloration or as a blood-filled blister.
The damage can occur beneath the skin and may evolve rapidly.
Symptoms of Pressure Ulcers
Early recognition can help prevent progression.
Possible signs include:
- Persistent skin discoloration
- Localized warmth or coolness
- Swelling
- Pain or tenderness
- Changes in skin texture
- Blistering
- Open wounds
- Drainage
- Skin breakdown
- Dark red, purple, or maroon discoloration
- Visible deeper tissue in advanced wounds
People with reduced sensation may not experience pain even when significant tissue damage is present.
How Are Pressure Ulcers Diagnosed?
Diagnosis is usually based on a physical examination and assessment of the wound.
Healthcare professionals may evaluate:
- Location
- Size
- Depth
- Tissue type
- Skin condition
- Drainage
- Odor
- Signs of infection
- Pain
- Surrounding skin
- Mobility
- Nutritional status
- Continence
- Pressure and shear risks
A comprehensive assessment should also consider the patient’s overall health and ability to reposition.
Treatment of Pressure Ulcers
Treatment depends on the stage, depth, location, presence of infection, nutritional status, and overall health.
Relieve Pressure
The first priority is to remove or reduce pressure from the affected area.
This may involve:
- Repositioning
- Pressure-redistributing mattresses
- Specialized cushions
- Heel protection
- Positioning devices
- Changes in sitting or lying position
Simply treating the wound while continuing the pressure that caused it may prevent healing.
Wound Care
Appropriate wound care helps maintain a suitable environment for healing.
Depending on the wound, clinicians may use dressings that manage moisture, absorb drainage, protect surrounding skin, or support the healing process.
The dressing should be selected according to the wound characteristics rather than using the same product for every pressure injury.
Debridement
Dead or nonviable tissue may interfere with healing and, when appropriate, may need to be removed through debridement.
The appropriate method depends on the wound, the patient’s condition, infection status, blood supply, pain level, and clinical circumstances.
Infection Management
Pressure injuries can become infected, particularly when tissue damage is extensive.
Signs that may raise concern include:
- Increasing redness around the wound
- Increasing warmth
- Swelling
- Pus-like drainage
- Increasing pain
- Foul odor
- Fever
- Worsening wound appearance
A healthcare professional should evaluate suspected infection. Antibiotics are not automatically required for every pressure ulcer and should be used when clinically indicated.
Nutrition and Hydration
Adequate nutrition is an important component of pressure-injury prevention and healing.
The 2025 NPIAP guideline update recommends comprehensive nutritional assessment for people at risk who are identified as malnourished and supports individualized nutrition care. It also recommends adequate hydration and nutrient-dense food, with nutritional or protein supplementation considered when needs are not being met through usual dietary intake.
People with significant wounds may benefit from assessment by a qualified healthcare professional or dietitian.
Pressure Ulcer Prevention
Prevention is often easier than treating an advanced pressure injury.
Reposition Regularly
People who cannot move independently should be repositioned according to an individualized care plan.
The appropriate frequency depends on the person’s condition, skin tolerance, support surface, mobility, and other clinical factors.
Inspect the Skin
Regular skin assessment can identify early changes before a wound becomes severe.
Pay particular attention to bony areas and areas exposed to pressure, moisture, or friction.
AHRQ recommends comprehensive skin assessment and pressure-injury risk assessment as important components of prevention programs.
Use Pressure-Redistributing Surfaces
Specialized mattresses, cushions, and other support surfaces can help redistribute pressure.
The appropriate surface depends on the person’s mobility, body size, risk level, and care environment.
Keep Skin Clean and Dry
Clean the skin gently and manage moisture appropriately.
People with urinary or fecal incontinence may require individualized skin-protection strategies.
Maintain Good Nutrition
Adequate calories, protein, fluids, vitamins, and minerals are important for overall health and wound healing.
People who are malnourished or at risk of malnutrition may require individualized nutritional support.
Avoid Excessive Friction
Use appropriate techniques when moving or transferring a patient. Avoid dragging a person across the bed or chair because this can damage the skin.
Pressure Ulcer Prevention in Hospitals
Hospitals can reduce pressure injuries through organized prevention programs.
AHRQ recommends a structured approach involving risk assessment, comprehensive skin assessment, individualized care planning, staff education, implementation of prevention practices, measurement, and ongoing improvement.
Effective prevention is not simply the responsibility of one nurse or caregiver. It generally requires collaboration among nurses, physicians, wound-care specialists, dietitians, rehabilitation professionals, patients, and families.
AHRQ’s implementation model also emphasizes monitoring outcomes and sustaining prevention practices over time.
Pressure Ulcers in Bedridden Patients
People who remain in bed for extended periods are at increased risk because prolonged pressure can develop over the same areas.
Prevention may include:
- Regular repositioning
- Appropriate mattress selection
- Heel protection
- Frequent skin checks
- Moisture management
- Adequate nutrition and hydration
- Mobility or range-of-motion activities when appropriate
- Avoiding unnecessary friction and shear
The care plan should be individualized rather than relying on a single repositioning schedule for everyone.
Can Pressure Ulcers Heal?
Yes, many pressure injuries can heal, particularly when recognized early and treated appropriately.
Healing depends on:
- Pressure relief
- Wound depth
- Blood supply
- Nutrition
- Infection control
- Overall health
- Mobility
- Appropriate wound care
- Consistent prevention of further injury
Deep Stage 3 and Stage 4 injuries can take considerably longer to heal and may require specialized wound care.
Possible Complications
Untreated or severe pressure injuries can lead to complications such as:
- Cellulitis
- Wound infection
- Abscess
- Osteomyelitis
- Sepsis
- Significant tissue loss
- Delayed healing
- Chronic wounds
Pressure ulcers are associated with pain, serious infection risk, increased healthcare utilization, and longer hospital stays.
When Should You Seek Medical Care?
A healthcare professional should evaluate a suspected pressure ulcer, particularly when the skin is broken or the area is worsening.
Prompt medical attention is especially important if there is:
- Rapidly increasing redness or discoloration
- A deep or enlarging wound
- Pus-like drainage
- Fever
- Severe or increasing pain
- Foul-smelling drainage
- Black or necrotic tissue
- Exposed bone, tendon, or muscle
- Signs of spreading infection
People with diabetes, poor circulation, impaired sensation, severe illness, or significant mobility limitations may require particularly careful monitoring.
Conclusion
A pressure ulcer is a preventable and treatable type of tissue injury caused mainly by prolonged pressure, often combined with shear. It can range from an early change in intact skin to extensive tissue loss involving deeper structures.
Early identification, regular skin assessment, pressure relief, appropriate support surfaces, moisture management, adequate nutrition, and individualized wound care are central to prevention and treatment. AHRQ’s pressure-injury resources emphasize structured risk assessment, skin assessment, care planning, implementation, measurement, and continuous quality improvement.
Anyone who develops a persistent area of skin discoloration, blistering, or an open wound—especially over a bony prominence—should receive appropriate medical or nursing assessment. Advanced or infected pressure injuries require professional wound management.
10 Frequently Asked Questions About Pressure Ulcers
1. What is a pressure ulcer?
A pressure ulcer is localized damage to the skin and underlying tissue caused mainly by prolonged or intense pressure, often combined with shear.
2. Where do pressure ulcers commonly occur?
Common locations include the tailbone, heels, hips, ankles, elbows, back of the head, shoulder blades, and other areas where bone is close to the skin.
3. What are the stages of pressure ulcers?
Pressure injuries are classified as Stage 1, Stage 2, Stage 3, and Stage 4. There are also classifications for unstageable pressure injuries and deep tissue pressure injuries.
4. What is a Stage 1 pressure ulcer?
Stage 1 involves intact skin with localized persistent non-blanchable discoloration, generally over a bony prominence. Other changes in temperature, firmness, or sensation may also occur.
5. Can pressure ulcers be prevented?
Yes. Prevention includes risk assessment, regular skin inspection, pressure redistribution, repositioning when appropriate, moisture management, good nutrition, hydration, and minimizing friction and shear.
6. How do you treat a pressure ulcer?
Treatment depends on the stage and condition of the wound. It may include pressure relief, specialized support surfaces, wound dressings, debridement when appropriate, infection management, and nutritional support.
7. Are pressure ulcers painful?
They can be painful, particularly during movement or wound care. However, people with reduced sensation may have little or no pain despite significant tissue damage.
8. Can a pressure ulcer become infected?
Yes. Pressure ulcers can become infected, particularly when they are deep or extensively damaged. Increasing redness, swelling, drainage, odor, pain, or fever may indicate infection and requires medical assessment.
9. What foods help pressure ulcer healing?
A balanced, nutrient-dense diet with adequate protein and fluids supports overall healing. People at risk of malnutrition may need individualized nutritional assessment and supplementation.
10. When is a pressure ulcer serious?
Any open pressure injury deserves appropriate assessment. Deep wounds, rapidly worsening discoloration, exposed deeper tissues, significant drainage, fever, severe pain, or signs of spreading infection require prompt professional care.
