Eschar is dead, necrotic tissue that forms a hard, black or dark brown crust over a wound bed. This tissue is typically leathery, dense, and firmly attached to the underlying healthy tissue. It is commonly seen following full-thickness injuries, such as severe burns, or in cases of compromised circulation that lead to pressure ulcers. Eschar prevents a wound from healing because it acts as a physical barrier, blocking cell migration and providing a medium for bacterial growth. Treatment focuses on debridement, which is the necessary removal of this non-viable tissue to expose a healthy wound base and allow the natural healing process to begin.
Determining the Need for Removal
The initial step in managing eschar is a careful assessment to determine if and when intervention is appropriate, as not all eschar should be removed immediately. Clinicians distinguish between two primary states: stable and unstable eschar.
Stable eschar is dry, intact, firmly adhered to the wound edges, and shows no signs of surrounding infection, such as redness, swelling, or drainage. This stable tissue, particularly when located on the heel or other ischemic areas with poor blood flow, may be left alone temporarily. In these specific cases, the dry, leathery tissue acts as a natural biological dressing, protecting the compromised tissue underneath from external infection. The decision to leave it intact is made when removing it would expose the wound to a higher risk of infection or further damage due to poor circulation.
In contrast, unstable eschar requires immediate debridement because it signals an underlying problem that poses a risk to the patient. Unstable eschar is characterized by becoming soft, boggy, or wet, or by showing signs of local infection like foul odor, purulent drainage, or surrounding redness and warmth. Once the eschar is compromised, it harbors bacteria, dramatically increasing the risk of systemic infection or sepsis.
Techniques for Eschar Debridement
Once the decision is made to remove the dead tissue, several distinct debridement techniques are available, chosen based on the wound’s condition and the patient’s overall health.
Surgical or Sharp Debridement
This is the most rapid and aggressive method, using a sterile scalpel or scissors to physically cut away the necrotic tissue. This procedure is typically performed by a trained healthcare professional and is often reserved for unstable or heavily infected eschar where rapid removal is necessary to control the infection. While aggressive tissue removal may sometimes occur in an operating theater, conservative sharp debridement can be done at the bedside.
Autolytic Debridement
This slower, gentler approach harnesses the body’s own natural enzymes to break down the eschar. This method requires the application of specialized moisture-retentive dressings, such as hydrogels or hydrocolloids, directly onto the wound. By maintaining a moist environment, these dressings rehydrate and soften the hard eschar, allowing the body’s enzymes to selectively liquefy the dead tissue. Autolytic debridement is the most selective and least painful method, but it is also the slowest and is generally not appropriate for infected wounds that require immediate cleansing.
Enzymatic Debridement
Enzymatic debridement employs topical pharmaceutical agents, like collagenase, applied directly to the eschar. These enzymes chemically digest the necrotic tissue by selectively targeting and breaking down the structural proteins that hold the eschar in place. This technique offers a balance between the speed of sharp debridement and the selectivity of autolytic methods, typically working within days to weeks without damaging the surrounding healthy tissue.
Mechanical Debridement
Mechanical debridement relies on physical force to remove the dead tissue, often serving as an initial cleansing method before other techniques are employed. This involves wound irrigation, where pressurized saline or water is used to wash away loose debris and surface eschar.
Post-Removal Wound Management
Once the eschar has been successfully removed, the focus shifts entirely to managing the underlying wound bed. The primary goal of post-removal care is to promote the formation of healthy granulation tissue and subsequent re-epithelialization. This is achieved by maintaining a consistently moist wound environment, which accelerates cell migration and proliferation.
Selecting the appropriate secondary dressing depends on the amount of fluid, or exudate, the newly exposed wound produces. Highly absorbent dressings, such as alginates or foams, are often used if the wound is heavily draining. For wounds with low to moderate exudate, hydrocolloids or specialized hydrogels can be used to maintain the necessary moisture balance and protect the new tissue.
Infection prevention is a constant concern following debridement, as the protective eschar has been removed. The wound must be closely monitored for signs of developing cellulitis, such as spreading redness, fever, or increasing pain. Regular cleansing and appropriate topical agents may be used to minimize the bacterial load, ensuring the wound bed remains conducive to healing.