Eschar is a patch of dead tissue that sits on a wound’s surface, and it has a distinctive look: thick, dry, and leathery, usually dark brown to black, though it can range from tan to gray depending on the cause and how long it has been forming. It feels hard or rubbery to the touch and does not bleed when pressed. The word itself comes from the Greek for “scab,” but eschar is far thicker and more structured than an ordinary scab. Because eschar forms in several very different clinical situations, from severe burns to pressure injuries to certain infections, its exact appearance shifts with context in ways that matter for treatment decisions.
The General Appearance
At its most recognizable, eschar looks like a tough, darkened patch of skin that has lost all flexibility. Picture a piece of leather glued to the wound surface. The color typically falls somewhere between deep tan and coal black, with darker shades indicating tissue that has been dead longer or has dried more completely. The surface is usually smooth or slightly ridged, and the edges may curl slightly where they start to separate from the living tissue around them. Unlike a normal scab, which is relatively thin and crumbly, eschar can be several millimeters thick and resistant to being peeled away.
Underneath that leathery cap, the tissue is largely necrotic. In adults with deep burns, histological examination of excised eschar found roughly 90 percent of the tissue was dead, with only about 10 percent still viable and marked by inflammation. In children, the picture differed: excised eschar sometimes contained up to 50 percent viable tissue, likely because pediatric skin is thinner and the injury pattern is different.1Burns. Histological investigation of burn eschar and the underlying recipient area in tangential early excision of burns That internal composition is invisible to the eye, but it explains why eschar feels so stiff and unyielding compared to healthy skin: most of what you are touching is dead, dehydrated protein.
The texture matters clinically. When wound care professionals describe eschar as “leathery,” they mean it resists indentation and does not blanch when you press on it. Blood flow to that tissue has stopped entirely, which is why it does not turn white under pressure the way living skin does. In chronic wounds, microscopic analysis reveals a surprisingly organized interior: fibrous regions interspersed with more irregular, amorphous zones, plus immune cells (leucocytes) clustered near the wound bed where the body is trying to break the dead tissue down.2PubMed. The structure and composition of chronic wound eschar That structural complexity is one reason eschar is so stubborn to remove.
Eschar on Burns
Burns are the context where most people first encounter the word eschar. In a full-thickness burn, the heat destroys the entire depth of the skin, and the resulting dead tissue dries into a rigid shell. The color depends on the type of burn. Dry-heat burns tend to produce tan, brown, or charred-black eschar. Scalds (hot liquid burns) may form a paler, waxy-looking eschar that is white or grayish before it darkens over the following days. Chemical burns can produce unusual colors depending on the chemical involved, sometimes yellowish or greenish before darkening.
A defining visual feature of burn eschar is that the burned area looks sunken relative to the surrounding swollen skin. The eschar itself does not swell because it has lost all elasticity, while the living tissue around it swells with fluid as the body mounts an inflammatory response. This mismatch creates a characteristic “depressed island” appearance, with puffy, reddened skin surrounding a flat, hard, discolored center.
That rigidity is not just cosmetic. Full-thickness burn eschar is described clinically as “noncompliant,” meaning it does not stretch. When the tissues underneath swell during fluid resuscitation, the rigid eschar acts like a tourniquet, compressing blood vessels and potentially cutting off circulation to the limbs or restricting chest expansion if the burn wraps around the torso.3PubMed Central / Oxford Academic. Surgical Escharotomy and Decompressive Therapies in Burns This is why surgeons sometimes perform escharotomy, a procedure where they cut through the eschar to relieve pressure beneath it. In that situation, recognizing the tough, inelastic quality of the tissue is a matter of urgency.
Burn eschar also creates a unique treatment challenge. Standard antimicrobial creams and wound dressings used for other types of wounds are often ineffective on deep burns precisely because they cannot penetrate the eschar. Bacteria can colonize the plane just beneath it, sheltered from topical treatments by that thick barrier of dead tissue.4PubMed Central. Burn wound: How it differs from other wounds? So while the eschar may look like it is protecting the wound, it can actually be hiding infection underneath.
Eschar on Pressure Injuries
Pressure injuries, commonly called bedsores or pressure ulcers, are the other major context where eschar appears. These develop when sustained pressure cuts off blood flow to the skin, usually over bony areas like the sacrum (tailbone), heels, hips, or shoulder blades. When the tissue dies, it can form a patch of eschar that looks quite different from burn eschar in its early stages.
Heel eschar is especially common and has a distinctive look: a rounded or oval patch of dark, dry tissue sitting directly over the bony prominence of the heel. It often appears well-defined, with a sharp border between the dark dead tissue and the surrounding skin. In many cases, the eschar is firmly adherent, meaning it is tightly stuck to the underlying tissue and does not lift easily at the edges. The color ranges from dark brown to black, and the surface may look slightly shiny or matte depending on how dry it is.
One tricky aspect of pressure injury eschar is that it can mask the true depth of the wound underneath. Clinicians cannot accurately stage a pressure injury while eschar covers it because there is no way to see whether the damage extends into muscle, tendon, or bone without removing the dead tissue first. A heel covered by a dry, stable, firmly attached eschar with no signs of infection (no redness spreading around the edges, no drainage, no foul smell, no softening) is sometimes monitored rather than immediately debrided, because the eschar acts as a natural biological cover in that specific location. But if any of those warning signs appear, the eschar needs to come off so the wound beneath can be assessed and treated.
Eschar in Infections
Several infectious diseases produce eschar as a hallmark sign, and in these cases the appearance carries diagnostic weight.
Cutaneous anthrax is perhaps the most textbook example. After exposure to anthrax spores through a break in the skin, the infection typically begins with itching and a small raised bump that looks like an insect bite. Over one to two days, a ring of small blisters forms around the central lesion, some of them filled with clear fluid and others with blood. The center then collapses into a painless, depressed black eschar, usually round and well-demarcated, sitting within a zone of significant swelling and redness. That combination of features, black eschar surrounded by pronounced edema, vesicles, and hemorrhagic vesicles, is considered classic for cutaneous anthrax and is often the clue that prompts diagnosis.5PubMed Central. In-depth exploration of cutaneous anthrax: clinical and pathological manifestations of a case report The word “anthrax” itself comes from the Greek for coal, a reference to the coal-black color of the eschar.
Rickettsial infections like scrub typhus also produce a characteristic eschar at the site where an infected mite or tick fed. These eschars tend to be smaller than anthrax eschars, often around 5 to 15 millimeters across, and they look like a dark, punched-out crater with a raised, reddened border. They are sometimes described as resembling a cigarette burn. The location is often in a warm, moist fold of the body, such as the groin, armpit, or behind the ear, because that is where the mites prefer to attach. Finding such an eschar on a patient with fever and headache in an endemic area can clinch the diagnosis.
Spider bites, particularly from the brown recluse, can produce a localized area of skin death that develops an eschar-like appearance. The initial bite may cause a red, painful area that evolves over hours to days into a darkened, necrotic wound. A case report described a patient who developed both systemic symptoms and a dermonecrotic wound after a brown recluse bite, with the local tissue damage progressing through stages of redness, blistering, and eventual tissue death.6PubMed Central. A Case Report of Brown Recluse Spider Bite The resulting eschar is usually irregular in shape, following the pattern of venom spread rather than the neat circles seen in anthrax or tick-borne disease.
Eschar in Vascular Disease
When blood supply to the skin is compromised by vascular problems rather than external injury or infection, the resulting tissue death can also produce eschar, but it tends to look different and follow a different pattern.
Calciphylaxis is a serious condition, most common in people with advanced kidney disease, in which calcium deposits block small blood vessels in the skin. The clinical picture includes painful areas of mottled, purplish discoloration that progress to open sores and eventually to black eschars. The visual presentation can be quite variable; features described include purpuric patches and plaques, blistering, irregularly shaped ulcers, and black eschars.7PubMed Central. Calciphylaxis with peau d’orange induration and absence of classical features of purpura, livedo reticularis and ulcers The eschars in calciphylaxis tend to appear on areas with more subcutaneous fat, like the thighs, abdomen, and buttocks, rather than over bony prominences like pressure injury eschar. They are often surrounded by areas of dusky, mottled skin that suggest more tissue is at risk.
Peripheral arterial disease can also produce eschar, typically on the toes and feet, when blood flow is so compromised that patches of tissue die. These eschars are usually dry, black, and well-circumscribed, and they may sit at the tips of the toes or along the edges of the foot. In contrast to pressure injury eschar, which results from external force, arterial eschar reflects internal vascular failure and often appears alongside other signs of poor circulation like cold skin, absent pulses, and thin, shiny skin on the lower legs.
How to Tell Eschar from Slough
One of the most common visual mix-ups is confusing eschar with slough. Both are types of dead tissue found in wounds, but they look and behave quite differently.
Slough is soft, moist, and typically yellow, tan, or grayish-white. It has a stringy or mucus-like consistency and can often be wiped or gently pulled away from the wound bed. Eschar, by contrast, is hard, dry, and dark. It is firmly attached and resists removal. Think of slough as wet dead tissue and eschar as dry dead tissue. The distinction matters because they require different approaches to removal, and their presence suggests different things about what is happening in the wound.
Sometimes the two coexist. A wound may have a central area of hard black eschar surrounded by a margin of softer, yellowish slough where the eschar is beginning to separate. The edges of eschar often soften and become slough-like as the body’s own enzymes work to break down the dead tissue from beneath, a process called autolytic debridement. Seeing that transition, hard dark center giving way to softer, lighter margins, is actually a sign that the body is making progress in clearing the dead tissue.
Color Changes and What They Signal
Eschar does not stay the same color throughout its lifespan, and tracking those changes tells you something about what is happening underneath.
Fresh eschar may start out pale or grayish, especially in scald burns or early pressure injuries. As the tissue dehydrates and the hemoglobin in trapped blood breaks down, the color darkens toward brown and then black. A very dark, dry, firmly attached eschar that is not changing may be relatively stable. But color shifts in certain directions are red flags.
If eschar that was previously dry and dark begins to soften, turn greenish, or develop a foul smell, infection is likely present beneath it. The green tinge often indicates bacterial colonization, particularly by Pseudomonas species, which produce pigmented metabolites. Any new redness spreading outward from the edges of the eschar into the surrounding skin, called cellulitis, is another warning sign. Similarly, if fluid begins to seep out from under the edges of previously dry eschar, something has changed beneath it and the wound needs reassessment.
Conversely, when eschar begins to lift at its edges and the tissue visible underneath looks pink, moist, and granular (like tiny red berries packed together), that is healthy granulation tissue forming. The wound is healing from below and pushing the dead cap off. This is a good sign, though the process can take weeks depending on the wound’s size and location.
Removing Eschar
Debridement, the removal of dead tissue, is a central part of wound care when eschar is present, though the timing and method depend heavily on the situation.
In some cases, wound care teams use sharp debridement, physically cutting the eschar away with a scalpel or scissors. One clinical report described patients with “leathery necrotic eschar” on chronic wounds that had not responded to moisture-based dressings like hydrogels or hydrocolloids. Using a specialized capillary dressing under a vapor-permeable film, the wound margins showed signs of separation within days, and within a week the eschar could be sharply debrided to prepare the wound for healing.8PubMed. Debridement of necrotic tissue and eschar using a capillary dressing and semi-permeable film dressing That sequence, softening the edges and then cutting, is a common strategy because trying to cut firmly adherent eschar without any separation risks damaging viable tissue beneath it.
Other debridement methods include autolytic debridement (using moisture-retaining dressings to let the body’s own enzymes dissolve the dead tissue gradually), enzymatic debridement (applying topical enzyme preparations that break down necrotic tissue), and mechanical debridement (physically loosening tissue with wet-to-dry dressings or irrigation). Each approach has a different visual timeline. Autolytic debridement is the slowest but least invasive: you will see the eschar gradually soften, become boggy, and shrink at its edges over days to weeks. Enzymatic debridement often produces a fibrinous, yellowish wound surface as the dead tissue dissolves. Sharp debridement is immediate and dramatic, leaving a red, bleeding wound bed that, while alarming-looking, is often exactly what clinicians want to see because it means viable tissue is exposed and can begin healing.
When Advanced Imaging Steps In
One frustration with eschar is that it hides the wound beneath it. You can look at a patch of dark, leathery tissue and have no idea whether the damage extends a few millimeters deep or all the way to bone. Clinical judgment and physical examination help, but newer imaging technologies are starting to offer more objective assessments.
Hyperspectral imaging, which captures light across many wavelengths beyond what the human eye can see, has been evaluated for burn wound assessment. A study of burn wounds on the upper extremity found that hyperspectral imaging could effectively differentiate between burn depths, including distinguishing superficial partial-thickness burns from deep partial-thickness burns based on tissue oxygenation and perfusion measurements.9PubMed Central / Elsevier. Evaluation of hyperspectral imaging as a modern aid in clinical assessment of burn wounds of the upper extremity The technology essentially sees through the surface to assess blood flow in the tissues below, giving clinicians a functional picture that the naked eye cannot provide. While not yet standard in every burn center, tools like these represent a shift toward treating eschar not just based on what it looks like on top, but on what the tissue underneath is doing.
For most people encountering eschar outside a clinical setting, the practical takeaway is simpler: if you see a patch of hard, dark, leathery tissue on a wound that is not healing, that is almost certainly eschar, and it deserves professional evaluation. The visual appearance alone can tell you a lot, but what matters most is what you cannot see beneath it.