A full-thickness skin injury caused by pressure, shear, or friction can damage tissue beyond the surface. Staging depends on the deepest tissue involved, not the wound’s size or surface appearance. You may see crater-like skin loss, exposed fat, or tissue that hides the injury’s true depth.
This overview explains pressure-injury stages, deeper skin loss, warning signs, treatment planning, and practical steps you can take while arranging professional wound care.
Pressure Injuries and Their Stages
A pressure injury is damage to skin or underlying tissue caused by pressure, pressure combined with shear, or friction. Shear occurs when you slide across a surface, such as shifting down in a bed while your skin remains in place. These forces can reduce blood flow and damage living tissue.
Staging gives clinicians a shared way to describe an injury’s depth. The range extends from intact skin or a shallow open wound to damage involving muscle, tendon, cartilage, or bone. This language follows widely used pressure-injury classifications developed by the National Pressure Injury Advisory Panel.
| Stage or category | What it describes | Key point |
|---|---|---|
| Stage 1 | Intact skin with pressure-related changes | The skin remains unbroken |
| Stage 2 | Partial-thickness skin loss | Adipose tissue is not exposed |
| Stage 3 | Full-thickness skin loss | Fat may be exposed or directly palpable |
| Stage 4 | Full-thickness tissue loss | Deeper structures are exposed or directly palpable |
| Deep tissue pressure injury | Pressure-related damage beneath intact or injured skin | The depth cannot be staged until it becomes clear |
| Unstageable | Depth cannot be identified reliably | Obscured tissue hides the deepest layer |
Your wound’s width, color, or location does not determine its stage by itself. A small, deep injury can cause more harm than a wider, shallow area, so your clinician examines the wound bed and the deepest identifiable tissue.
Staging matters because treatment and pressure-relief decisions depend on tissue depth, wound-bed conditions, and your overall risk. A surface photograph can show color and drainage, but it may not reveal the tissue that determines the stage. You should avoid labeling a wound from appearance alone.
Because surface appearance can conceal deeper tissue damage, the wound’s depth and exposed layers determine how it should be staged.
Full-Thickness Loss and Exposed Tissue
Because the stage depends on the deepest identifiable tissue, the defining finding is loss through the epidermis and dermis into the subcutaneous layer. Subcutaneous tissue is the fatty layer beneath the skin. In this stage, fat may be visible or directly palpable, although covering material can hide it.
Full-Thickness Loss
Beyond the superficial skin layers, damaged tissue may extend through the dermis into deeper structures. Your wound bed may contain exposed fat, granulation tissue, slough, drainage, or a combination of findings. The wound’s edges can be thin, rolled, reddened, swollen, or irregular, but those surface details do not replace depth assessment.
Yellow, white, or gray fatty tissue does not by itself mean that muscle or tendon is exposed. Adipose tissue often has a soft, lobulated appearance, but color alone cannot establish depth. Your clinician assesses what is visible, what can be gently palpated, and what remains uncertain.
The depth category is especially important when the wound bed is covered. A small opening can conceal a larger area of tissue loss, and a covered area can look shallower than it is. Clinical examination of the wound bed provides more reliable staging information than visual size or color alone.
Terms You May Encounter
You may encounter older labels such as pressure sore or third-degree pressure ulcer. Some records use stage 3 pressure injury. These terms generally describe the same deep skin-loss category, although documentation practices can vary by facility.
Slough is yellow or soft devitalized tissue, meaning tissue that is no longer healthy. It can cover part of the wound bed and conceal the deepest layer. Eschar is firm, dead tissue that may appear black, brown, or leathery. You shouldn’t remove either tissue at home merely to determine a stage.
Because these coverings can hide the wound bed, staging depends on the deepest identifiable tissue. Fat may not be visible when you look at the wound, yet it could still be directly palpable beneath slough. That uncertainty calls for clinical assessment, not probing.
Older terms can still appear in records, medication lists, or discharge instructions. When you compare information, focus on the documented tissue depth rather than the label alone. If your records use a different term, ask a wound-care specialist to explain what tissue was identified.
Visible Signs and Hidden Wound Features
The visible opening may show only part of the injury. A crater-like appearance can indicate deeper skin loss, but slough, drainage, or a dressing can conceal the wound bed. Your assessment should consider both what you see and what a trained clinician can safely identify.
Appearance of the Wound
A common appearance is a crater-like opening with loss of the epidermis, dermis, and deeper skin tissue. The wound may contain exposed fat, granulation tissue, slough, drainage, or a combination of these findings. Its edges can look rolled, thin, reddened, swollen, or irregular.
Granulation tissue is new, fragile tissue that may appear red, moist, and bumpy. Your clinician may also note a foul odor, a change in drainage, or skin that is warm, red, or swollen around the wound. Drainage can range from clear or cloudy to pink or yellow, depending on the wound and its surroundings.
Drainage, odor, color, and pain can change as a wound evolves. You should record when a change began and whether it followed dressing changes, movement, or a new medication. A wound-care specialist can use those details alongside examination findings to guide the plan.
Features Extending Beyond the Opening
Undermining means tissue has been lost beneath the skin edge, leaving a pocket that extends outward from the visible wound. Tunneling is a narrow passage that extends into deeper tissue. You may notice a small opening even though the injured area reaches farther beneath the surface.
These hidden features affect the area requiring care and complicate dressing selection. A wound-care specialist may use gentle assessment methods and selected tools to understand the wound’s shape. Keep probes, swabs, and other objects out of a deep opening unless a trained clinician directs their use.
Undermining and tunneling can also make home measurements unreliable. You should not push a swab or probe into the opening to check its depth, because the movement can damage tissue or introduce contamination. The wound-care specialist can document the tract and select a dressing plan suited to the actual shape.
- Crater shape: A recessed opening may reflect loss of deeper skin tissue.
- Covered tissue: Slough or fat can conceal the wound’s deepest identifiable layer.
- Hidden extension: Undermining or tunneling may extend beyond the visible opening.
- Changing drainage: New or increasing fluid can signal a change in wound conditions.
- Surrounding changes: Redness, warmth, swelling, or tenderness may need prompt review.
These findings are more useful when you describe them with specific details. Tell your clinician where the redness ends, when the drainage changed, and whether the opening is enlarging. Precise observations help your team distinguish routine wound changes from possible infection or pressure-related deterioration.
How This Injury Differs From Other Pressure Injuries
The boundary between stages depends on which tissue is exposed or can be directly felt. Surface appearance alone can mislead you, especially when slough covers the wound bed. The comparison below shows the depth findings that matter most.
| Category | Typical depth finding | How it differs |
|---|---|---|
| Stage 2 | Partial-thickness loss with exposed or palpable dermis | Fat, muscle, and tendon are not exposed |
| Stage 3 | Full-thickness loss with exposed or palpable adipose tissue | Fat may be covered by slough |
| Stage 4 | Exposed or palpable fascia, muscle, tendon, cartilage, or bone | Deeper structures distinguish it from stage 3 |
| Deep tissue pressure injury | Deep pressure damage beneath skin that may remain intact | It may resemble a bruise, discoloration, or blood-filled blister |
| Unstageable | The deepest tissue cannot be identified | Slough or eschar prevents reliable staging |
Exposed fascia, muscle, tendon, cartilage, or bone points to stage 4 rather than stage 3. Damage that begins beneath intact skin may resemble a bruise, discoloration, or blood-filled blister. Avoid assigning a stage from a photograph alone, especially when the wound is covered or changing.
Stage 2 stops at partial-thickness loss, so fat is not exposed or directly palpable. Stage 3 extends into the subcutaneous layer, where adipose tissue may be visible or palpable. Stage 4 reaches deeper structures such as fascia, muscle, tendon, cartilage, or bone, so the two categories differ by the deepest involved tissue.
Deep tissue pressure injury can remain unstageable when its depth is not visible. Unstageable pressure injury also has an obscured wound bed, usually because slough or eschar prevents reliable identification of the deepest layer. Your clinician must evaluate the wound before assigning a stage or selecting a treatment pathway.
Causes, Risk Factors, and Prevention
Prolonged pressure, shear, and friction can reduce blood flow and damage deep skin tissue. Limited movement, impaired sensation, poor circulation, diabetes, and weakened immunity can increase your risk. Bed rest and prolonged sitting may contribute when pressure relief is inadequate.
Pressure relief reduces the duration and intensity of loading over a vulnerable area. Your care plan may include regular repositioning, protection from friction and moisture, appropriate support surfaces, nutrition support, and dressings selected for the wound bed. A wound, ostomy, or continence nurse can help coordinate these choices.
For a person with reduced mobility, repositioning schedules should be individualized rather than applied mechanically. The Agency for Healthcare Research and Quality emphasizes risk assessment and prevention planning for pressure injuries, including attention to mobility, nutrition, moisture, and support surfaces. You can use that framework when discussing your next steps with a clinician.
Insensate skin may not produce a reliable warning pain signal, while reduced circulation can limit healing. You should check vulnerable areas during repositioning and care, especially the heels, sacrum, hips, and areas near medical devices. Your caregiver can help document changes that may be difficult to see.
- Relieve pressure: Reposition according to your care plan and use an appropriate support surface.
- Reduce friction: Avoid dragging your skin across sheets, chairs, or other surfaces during movement.
- Manage moisture: Keep the area clean and dry while following the wound-care plan.
- Inspect skin: Look for persistent redness, warmth, swelling, drainage, or an opening.
- Support nutrition: Discuss dietary needs and hydration with your healthcare professional.
- Seek assessment: Report a new deep opening, worsening pain, odor, or rapid change promptly.
Clinical Assessment and Wound-Care Planning
Because full-thickness skin loss can conceal deeper damage, your next step is prompt assessment by a qualified healthcare professional. Reduced mobility, impaired sensation, poor circulation, diabetes, weakened immunity, or prolonged bed rest can delay your response and reduce your ability to heal. These risk factors also shape pressure-injury prevention guidance from the Agency for Healthcare Research and Quality.
Components of an Assessment
A clinician records the wound’s location, dimensions, depth, edges, wound bed, and surrounding skin. The assessment may identify slough, granulation tissue, exposed fat, undermining, tunneling, drainage, odor, and signs of infection. Documentation also reviews your mobility, sensation, circulation, nutrition, and recent changes.
Your wound-care specialist may also assess whether the wound is worsening and whether pressure remains a direct cause. Measurements, photographs, drainage characteristics, and the presence of undermining or tunneling can help document progression. Your role is to report changes accurately and ask which findings require reassessment.
Care should match the wound’s features rather than rely on a household product or a single dressing. Dressing selection depends on the wound bed, exudate level, tissue condition, depth, and surrounding skin. A wound, ostomy, or continence nurse can coordinate the dressing plan with your overall pressure-relief and mobility needs.
Special Care Around Dry Eschar
Stable dry eschar on the heel or an ischemic limb should not be removed solely to determine the stage.
That rule matters because removing dry, stable tissue can create an opening for infection, particularly when blood flow is poor. Your clinician may assess circulation before making decisions about the eschar. Pressure relief remains central to protecting the area while the wound is evaluated.
Dry eschar can also obscure the deepest tissue and make staging unreliable. You should leave it in place unless a qualified clinician evaluates circulation and gives a specific instruction. The decision may differ when eschar is unstable, infected, accompanied by other wound findings, or located elsewhere on the body.
Those wound-specific findings shape treatment choices, so practical next steps depend on the clinician’s assessment rather than a standard label.
Treatment and Practical Next Steps
Treatment for a stage 3 pressure ulcer combines pressure relief, wound-bed care, protection from further injury, and management of contributing conditions. A qualified clinician determines the appropriate dressing and evaluates the wound’s depth. Your priorities are to protect the area and obtain professional guidance rather than attempt home treatment.
Your care plan may include pressure relief, regular repositioning, protection from friction and moisture, nutrition support, and dressings suited to the wound bed. Wound care should respond to changing drainage, slough, granulation tissue, odor, undermining, tunneling, or surrounding inflammation. Your wound-care specialist can revise the plan as the wound changes.
Keep dressings clean and follow the instructions provided for changing them. Do not soak the area, apply unapproved powders, or fill a deep opening with home remedies. If a dressing becomes wet, loose, or contaminated, follow the care plan and contact the appropriate clinician.
You can support the plan by limiting pressure on the area, avoiding rubbing, and reporting changes in pain, odor, drainage, or skin color. Bring a list of medications and recent mobility changes to the visit. Those details help your clinician consider circulation, sensation, infection risk, and healing needs.
Urgent Warning Signs and Next Steps
Spreading redness, increasing warmth, swelling, worsening pain, pus, foul odor, fever, chills, confusion, or a rapid decline in your health can signal infection or another serious change. These signs deserve urgent medical attention rather than a routine appointment days later. Infection can change the wound’s depth and the urgency of your care plan.
- Spreading redness: Redness moving beyond the wound edge needs prompt assessment.
- Increasing pain: New or worsening pain may reflect worsening tissue injury.
- Purulent drainage: Thick, cloudy, or foul-smelling fluid can raise concern.
- Systemic changes: Fever, chills, confusion, or marked weakness require urgent care.
- Rapid deterioration: A wound that enlarges or deepens quickly should not wait.
Don’t probe, cut, pack, or aggressively clean a deep wound without appropriate clinical guidance. Relieve pressure as safely as possible, protect the area from friction and moisture, and arrange a professional evaluation. When you seek care, describe the wound’s color, drainage, odor, pain, and recent changes.
Seek emergency care when infection signs appear with fever, chills, confusion, marked weakness, or rapid decline. A rapidly enlarging or deepening opening also requires prompt medical attention. You should not wait for a routine appointment when the wound’s condition is changing quickly.
Key Takeaways
This injury involves full-thickness skin loss with exposed or directly palpable fat, but covering tissue can hide that depth. Your priorities are prompt clinical assessment, pressure relief, and protection from further injury. A wound-care specialist can evaluate your wound bed and help guide appropriate care.
Your wound’s deepest identifiable tissue matters more than its width, color, or appearance. Stage 3 differs from stage 2 because the injury reaches the subcutaneous layer, and it differs from stage 4 because deeper structures are not exposed or directly palpable. Slough or eschar can prevent reliable staging, so a qualified clinician must examine the wound.
FAQ
What is a stage 3 pressure ulcer?
Full-thickness skin loss with exposed or directly palpable subcutaneous fat characterizes this injury. The deepest identifiable tissue determines the stage, even when slough covers the surface. Wound size and color alone cannot establish the stage.
What does a stage 3 pressure ulcer look like?
A crater-like opening may appear with exposed fat, granulation tissue, slough, drainage, or irregular edges. Undermining and tunneling can extend beneath the visible opening. A covered wound may look less deep than it really is.
How deep is a stage 3 pressure ulcer?
Damage may pass through the epidermis and dermis into subcutaneous tissue, exposing or revealing palpable fat. The wound does not necessarily expose fascia, muscle, tendon, cartilage, or bone. Slough can hide the deepest identifiable tissue.
How is a stage 3 pressure ulcer different from stage 2 and stage 4 pressure injuries?
Stage 2 involves partial-thickness loss without exposed or palpable fat, while stage 3 involves full-thickness loss with exposed or palpable adipose tissue. Stage 4 extends into exposed or palpable fascia, muscle, tendon, cartilage, or bone. Your clinician determines the category from the deepest identifiable tissue.
What causes stage 3 pressure ulcers?
Prolonged pressure, shear, and friction can reduce blood flow and damage deep skin tissue. Limited movement, impaired sensation, poor circulation, diabetes, and weakened immunity can increase your risk. Bed rest and prolonged sitting may contribute when pressure relief is inadequate.
Is a stage 3 pressure ulcer a medical emergency?
Prompt professional assessment is needed, particularly if infection or rapid deterioration is possible. Spreading redness, increasing warmth, swelling, worsening pain, pus, foul odor, fever, chills, confusion, or rapid decline requires urgent medical attention.
