Wound healing is a complex biological process. Sometimes, dead or devitalized tissue, known as slough and eschar, can accumulate within a wound. These forms of necrotic tissue impede natural healing. Both slough and eschar signal underlying tissue damage.
Understanding Slough
Slough refers to devitalized tissue that often appears as a yellowish, whitish, or tan material within a wound bed. Its texture can vary from soft, moist, and stringy to thick and gelatinous, sometimes even resembling a fibrinous film. This material is composed of dead cells, fibrin, white blood cells, and other proteinaceous debris that accumulate during the inflammatory phase of wound healing.
Slough forms as a byproduct of the body’s inflammatory response to injury, infection, or compromised blood flow. When neutrophils, a type of white blood cell, gather at a wound site to clear debris and fight infection, they may die off faster than macrophages can remove them, leading to slough accumulation. This buildup can prevent the formation of new, healthy tissue and may also create an environment conducive to bacterial growth, potentially leading to infection.
Understanding Eschar
Eschar is a type of devitalized tissue found in wounds, characteristically appearing as a dry, thick, and hardened covering. It typically presents with a dark brown or black coloration, often described as leathery in texture. This tissue forms as a result of deep tissue damage, severe burns, or conditions that cause significant reduction in blood supply, such as arterial insufficiency or prolonged pressure on the skin.
The formation of eschar signifies necrosis, or tissue death, where affected cells and blood have dried out and hardened. While often dry and firmly attached to the wound bed, eschar can sometimes be soft, boggy, or fluctuant, especially if infection is present underneath. This dark, non-viable tissue can act as a natural protective barrier, but it also impedes the visualization of the wound bed and can hinder the healing process.
Distinguishing Slough from Eschar and Their Importance
Distinguishing between slough and eschar is important for understanding the nature and depth of tissue damage within a wound. Slough is generally softer, moist, and appears yellow, white, or tan, often having a stringy or gelatinous consistency. It is typically composed of dead cells, fibrin, and other substances, and can be loosely or firmly adhered to the wound bed.
Eschar, in contrast, is characterized by its hard, dry, and often leathery appearance, typically black or dark brown. It is primarily composed of dried necrotic tissue, including skin, muscle, or fat, and is usually firmly attached to the wound surface. While eschar can serve as a protective barrier against infection in some cases, it often signifies deeper tissue damage and impaired healing, and its presence can obscure underlying conditions. Recognizing these differences guides general care considerations, as slough often requires removal to facilitate healing, while stable eschar, especially on certain areas like the heel, may be left intact if it is not infected and provides a protective covering.