Accurately identifying wound tissue is the foundation of every good treatment plan. Whether a wound bed is covered in healthy granulation tissue, stubborn slough, or a hardened eschar tells a clinician what phase of healing the wound is in, what’s blocking it, and what needs to happen next. Misreading the tissue type is one of the most common — and most consequential — mistakes in wound assessment.
This guide breaks down the major wound tissue types nurses, caregivers, and clinicians encounter every day: granulation tissue, slough, eschar, hypergranulation tissue, and epithelial tissue. Each section includes what it looks like, why it forms, and what it means for treatment, along with clinical photos to help you recognize each tissue type with confidence.
Wound Tissue Types at a Glance
| Tissue Type | Appearance | What It Means | Typical Action |
| Granulation | Red, moist, bumpy texture | Healthy proliferative healing; active angiogenesis | Protect and support continued growth |
| Pale granulation | Light pink, dull | Poor blood supply / angiogenesis | Debridement to stimulate new vessel growth |
| Slough | Yellow or white, stringy or thick | Devitalized tissue; blocks healing, breeds bacteria | Debridement |
| Eschar | Black, dry, leathery | Hardened necrotic tissue, often from pressure or burns | Debridement (with clinical evaluation) |
| Hypergranulation | Red, glossy, raised above skin edge | Overgrowth blocking epithelialization | Silver nitrate or debridement |
| Epithelial tissue | Pink/white, thin, flat | New skin forming over granulation tissue | Protect; monitor for reopening |
What Is Granulation Tissue?
Granulation tissue is the healthy, red, vascular tissue that forms in a wound bed during the proliferative phase of healing. It’s made up of new connective tissue and tiny capillary buds, and it’s one of the clearest visual signs that a wound is progressing in the right direction.
Granulation tissue forms through a process called angiogenesis — the formation of new blood vessels. As angiogenesis occurs, tiny capillary buds appear across the wound base, giving granulation tissue its characteristic “bumpy,” beefy-red appearance. Healthy wound buds protrude slightly from the wound bed, and the tissue should look moist, glistening, and deep pink to red.
Granulation tissue matters because it sets the stage for the next phase of healing: epithelialization. Without an adequate base of granulation tissue, epithelial cells have nowhere to migrate across, and the wound cannot close.
Healthy vs. Unhealthy Granulation Tissue
Not all granulation tissue looks the same, and color is one of the most important clues a clinician has.
- Healthy granulation tissue is deep red, moist, and slightly bumpy in texture, reflecting good blood flow and active angiogenesis.
- Pale or unhealthy granulation tissue appears lighter pink or dull, often signaling poor blood supply and reduced angiogenesis. Pale granulation tissue typically needs to be “freshened up” with debridement to stimulate new blood vessel ingrowth and restart the healing process.
If granulation tissue isn’t progressing — staying pale, friable, or stalled in size — it’s often a sign that an underlying issue (poor perfusion, infection, pressure, or nutritional deficits) needs to be addressed before the wound can move forward.
How to Measure Wound Granulation
Tracking how much of a wound bed is covered in granulation tissue is a standard part of wound documentation, and it’s one of the simplest ways to monitor whether a treatment plan is working.
Common methods include:
- Visual percentage estimation: Clinicians estimate what percentage of the total wound bed is covered by granulation tissue versus other tissue types (slough, eschar, epithelial tissue) at each assessment.
- Wound measurement grids and tracings: Clear acetate grids placed over the wound help standardize measurements of total wound area and granulation tissue coverage over time.
- Serial photography: Photographing the wound at consistent angles and distances during each visit allows for side-by-side comparison and more objective tracking of granulation tissue growth.
- Wound measurement apps and digital imaging tools: Some facilities now use digital wound photography platforms that automatically calculate tissue type percentages and wound dimensions.
Measuring granulation percentage isn’t just useful for clinical decision-making — it’s also critical for documentation and reimbursement, since payers and regulatory bodies often require objective evidence of wound progress. A wound that shows a steady increase in granulation tissue percentage over consecutive visits is generally considered to be healing appropriately; stalled or decreasing granulation tissue warrants a reassessment of the treatment plan.
Granulation Tissue vs. Fibrosis: What’s the Difference?
Granulation tissue and fibrosis are related but distinct parts of the wound healing process, and the two terms are often confused.
Granulation tissue is the temporary, highly vascular tissue that fills a wound defect during the proliferative phase. It’s rich in new capillaries and immature collagen, and its job is to provide a scaffold for epithelial cells to migrate across.
Fibrosis refers to the excess deposition of collagen that can occur during the remodeling phase of healing, or as a result of chronic inflammation. Unlike granulation tissue, fibrotic tissue is not actively vascularizing — it’s a denser, more permanent tissue made primarily of collagen fibers, and it’s what ultimately forms scar tissue.
In short: granulation tissue is a reparative, transitional tissue, while fibrosis is the longer-term structural result of collagen remodeling. Fibrosis becomes a clinical concern when it’s excessive, leading to hypertrophic scarring, contractures, or restricted mobility — particularly around joints or in burn injuries.
Necrotic Tissue: Slough and Eschar
Necrotic tissue refers to tissue that has died, usually due to a disruption in blood supply and oxygen delivery. In wound care, necrotic tissue typically presents in one of two forms — slough or eschar — and both need to be addressed before a wound can heal.
What Is Slough?
Slough is yellow or white devitalized tissue that separates from the surrounding living tissue. It can appear stringy and loosely attached, or thick and firmly adherent to the wound bed. Slough is extremely common in chronic wounds, including pressure ulcers, venous ulcers, and diabetic foot ulcers.
A single wound bed can contain both types of slough at once — some areas with loose, stringy yellow tissue and others with thick, tightly adherent slough. Because slough provides an ideal environment for bacterial growth and physically blocks the wound bed from forming healthy granulation tissue, it generally needs to be surgically or mechanically debrided to allow new tissue growth underneath.
Slough vs. Purulent Drainage
Slough and purulent drainage are often confused, but they’re not the same thing. Slough is a solid mass of dead tissue attached to the wound bed — it doesn’t drain or wipe away easily. Purulent drainage, on the other hand, is a liquid exudate, typically thick, opaque, and yellow, tan, or green in color, and it’s usually a sign of infection. A wound can have slough, purulent drainage, both, or neither — they’re separate findings that each carry their own clinical significance.
What Is Eschar?
Eschar is necrotic tissue that has become hardened — usually black, dry, and leathery in appearance. It forms when tissue death and dehydration occur together, and it can be firmly adherent to the wound bed or beginning to lift at the edges.
Eschar most commonly results from pressure ulcers, where sustained pressure occludes blood vessels and cuts off oxygen delivery to the underlying tissue. It can also form from burns, particularly thermal or electrical burns, where deep tissue damage causes the skin to dry out and blacken.
Eschar vs. Necrotic Tissue
Eschar and necrotic tissue are related but not interchangeable terms. Necrotic tissue is the broader category — any tissue that has died due to lack of blood supply. Eschar is a specific form of necrotic tissue: hardened, black, and dry. Slough is the other major form of necrotic tissue, but it’s soft, moist, and yellow or white rather than hard and black. In other words, all eschar is necrotic tissue, but not all necrotic tissue is eschar.
Eschar vs. Scab
Eschar and scabs are frequently mistaken for one another because both are dark, firm coverings over a wound — but they form through very different processes and signal very different things clinically.
A scab forms over a relatively superficial wound through the normal clotting process — platelets and fibrin create a protective crust over an injury as part of routine healing. Scabs are typically associated with shallow, uncomplicated wounds and don’t usually indicate underlying tissue death.
Eschar, by contrast, results from full-thickness tissue necrosis — the tissue underneath has actually died, most often due to pressure-related vascular occlusion or a deep burn. Eschar tends to be thicker, more leathery, and is frequently surrounded by signs of underlying tissue damage. Whether eschar should be debrided depends on clinical factors like blood supply to the limb and signs of infection underneath, which is why eschar management should always involve a wound care clinician.
In wound healing, all necrotic tissue — whether slough or eschar — generally needs to be debrided before a wound can progress to healthy granulation. For more advanced or deep wounds, this process may take multiple debridement sessions over weeks or months to achieve a clean, healthy wound bed.
A Closer Look: Necrotic Sacral and Sacrococcygeal Ulcers
Pressure ulcers in the sacral and sacrococcygeal region are some of the most common wounds clinicians see involving both slough and eschar in a single wound bed. Sustained pressure over the sacrum and coccyx — common in patients with limited mobility — occludes blood vessels and leads to tissue death below the surface.
A necrotic sacral ulcer often presents with a combination of dark eschar at the wound edges and softer slough toward the center, reflecting different stages and severities of tissue death across the wound. Because these ulcers can extend into deeper tissue layers, careful debridement and ongoing monitoring are essential to track the wound’s progression from necrotic tissue toward healthy granulation.
Hypergranulation Tissue
Hypergranulation tissue — sometimes called “proud flesh” — is an overgrowth of granulation tissue that rises above the surrounding skin edge. It’s not fully understood why hypergranulation occurs in some wounds, but it’s a relatively common complication, particularly around tracheostomy sites, gastrostomy tubes, and chronic wounds with prolonged moisture exposure.
Hypergranulation tissue is typically friable, meaning it bleeds easily with minimal contact, and it has a glossy, bumpy, deep red appearance that extends beyond the wound margin. Unlike normal granulation tissue, hypergranulation actually impedes healing — because it sits above the level of the surrounding skin, it blocks epithelial cells from migrating across the wound bed and laying down new collagen and epithelium.
Treating Hypergranulation Tissue
The most common treatment for hypergranulation tissue is the application of silver nitrate, which chemically cauterizes the excess tissue and causes it to regress over subsequent treatments. In some cases, hypergranulation tissue may also be surgically debrided to bring the wound bed back down to the level of the surrounding skin.
Epithelial Tissue and Epithelialization
Epithelialization is the final visible stage of wound closure, where new epithelial cells migrate across the surface of granulation tissue to form a continuous layer of skin. As this process unfolds, you may see small epithelial islands appear scattered across the wound bed before they eventually merge into a single, continuous area of new epithelium.
It’s worth noting an important clinical distinction: chronic wounds should technically be classified as re-epithelialized, not healed, once they close. Because the new epithelial layer over a chronic wound is more fragile than the surrounding mature skin, these areas remain at higher risk of reopening — particularly if the underlying cause of the wound (pressure, friction, poor perfusion) hasn’t been fully resolved.
Frequently Asked Questions
What is granulation tissue? Granulation tissue is the healthy, red, vascular tissue that forms in a wound bed during healing. It develops through angiogenesis and provides the foundation for new skin (epithelial tissue) to form on top of it.
What does granulation tissue look like? Healthy granulation tissue is deep red, moist, and slightly bumpy, reflecting the tiny capillary buds forming beneath the surface. Pale or dull granulation tissue suggests poor blood supply and often needs debridement.
What is slough in a wound? Slough is yellow or white devitalized tissue that separates from living tissue in a wound bed. It can be loose and stringy or thick and adherent, and it typically needs to be debrided before the wound can heal.
What is the difference between eschar and necrotic tissue? Necrotic tissue is the broader term for any dead tissue in a wound. Eschar is one specific form of necrotic tissue — hardened, black, and dry — while slough is the other major form, which is soft and yellow or white.
Is eschar the same as a scab? No. A scab forms over a superficial wound through normal clotting and doesn’t usually indicate deep tissue death. Eschar forms from full-thickness necrosis, most often due to pressure-related vascular occlusion or deep burns.
What causes hypergranulation tissue? The exact cause isn’t fully understood, but hypergranulation tissue is an overgrowth of granulation tissue above the wound edge, often seen around tubes, stomas, and chronically moist wounds. It’s friable and blocks epithelial migration.
How do you measure wound granulation? Clinicians typically estimate the percentage of the wound bed covered by granulation tissue at each visit, often supported by measurement grids, tracings, or serial photography to track changes over time.
What’s the difference between granulation tissue and fibrosis? Granulation tissue is a temporary, highly vascular tissue that fills a wound during healing. Fibrosis is the longer-term buildup of collagen during tissue remodeling, which ultimately forms scar tissue and can become problematic if excessive.
Accurately identifying wound tissue type is the first step toward effective treatment — but every wound is different, and the right next step depends on the full clinical picture. If you have questions about a specific wound, want to learn more about our wound care services, or are interested in wound care education and certification, the team at Wound Care Specialists is here to help.