Slough is considered to be part of the inflammatory process consisting of fibrin, white blood cells, bacteria and debris, along with dead tissue and other proteinaceous material. It is the cellular debris resulting from the process of inflammation7.
Necrotic tissue, slough, and eschar
The wound bed may be covered with necrotic tissue (non-viable tissue due to reduced blood supply), slough (dead tissue, usually cream or yellow in colour), or eschar (dry, black, hard necrotic tissue). Such tissue impedes healing.
Medical Definition
slough. 1 of 2 noun. ˈsləf. : dead tissue separating from living tissue. especially : a mass of dead tissue separating from an ulcer.
Initially fibrin(ogen) acts as a provisional matrix supporting incoming leukocytes and acting as reservoir for growth factors. It later goes on to support re-epithelialization, angiogenesis, and fibroplasia. Importantly, removal of fibrin(ogen) from the wound is essential for wound healing to progress.
Slough is marked by its color, which can be yellow, tan, gray, green, or brown. It can be stringy and loose or thick and adherent to the wound bed. It is imperative that slough be debrided to kick-start the healing process and allow for the ingrowth of healthy granulation tissue.
An essential component of wound bed preparation is the removal of slough from a wound bed. Slough not only contributes to delayed wound healing, it also prevents an accurate wound assessment and can also harbour biofilms.
Surgical debridement, or conservative sharp debridement, is performed with a scalpel, curette, or scissors to excise necrotic tissue. Surgical debridement is indicated for the removal of both slough and eschar. Tissue is frequently so that a margin of normal tissue is exposed if possible.
When tissue damage results in bleeding, fibrinogen is converted at the wound into fibrin by the action of thrombin, a clotting enzyme. Fibrin molecules then combine to form long fibrin threads that entangle platelets, building up a spongy mass that gradually hardens and contracts to form the blood clot.
Fibrin clots built as an immediate response to tissue injury, but need to be removed during the tissue remodeling phase.
Fibrin, commonly referred to as slough, is firmly adherent, tan to yellow-colored avascular tissue, which may be dry or slightly moist. This is not necrotic tissue, but rather a complex mixture of fibrins, degraded extracellular matrix proteins, exudates, white blood cells, and bacteria.
Stage 4: Full thickness tissue loss with exposed bone, tendon or muscle. Slough or eschar may be present on some parts of the wound bed. Often include undermining and tunneling.
If what you're cleansing out of the wound is stringy and yellow, and the wound base appears more granular after cleansing, it is most likely slough. If there is an odor, erythema, and signs and symptoms of infection, you're most likely dealing with purulence or purulent drainage.
In addition, studies show there's a link between diets high in red meat, sugar, and saturated fats and high fibrinogen levels. Therefore, eating more fruits and vegetables, and avoiding sugary, processed, and fast foods can help lower fibrinogen levels [39, 40].
Fibrin deposits are found in early multiple sclerosis lesions and areas of demyelination in close association with inflammation and damaged axons. In Alzheimer disease, fibrin deposits accumulate within CNS blood vessels in conjunction with cerebral amyloid angiopathy.
Too little fibrinogen can cause prolonged bleeding. But too much fibrinogen can cause you to form clots inside blood vessels. These clots could break loose and travel to your brain or your lungs, putting your life in danger.
Plasmin is the key enzyme in the fibrinolytic cascade dissolving blood clots. Plasmin functions as a nonspecific protease that trigger degradation of a variety of proteins in plasma and tissues as well as destroying blood clots.
Fibrin deposition within joints is a prominent feature of arthritis, but the precise contribution of fibrin(ogen) to inflammatory events that cause debilitating joint damage remains unknown.
SufA – a bacterial enzyme that cleaves fibrinogen and blocks fibrin network formation.
Slough will always show signs of stringy textures, yellow coloring, and will be more granular after cleansing. Purulence will always emit an odor after cleansing and will show signs of infection and erythema.
ActivHeal® Hydrogel is an effective method for hydrating dry necrotic and sloughy wounds.
One day after applying manuka honey the base of the wound could be seen to be clearing of slough.
Slough is defined as yellow devitalized tissue, that can be stringy or thick and adherent on the tissue bed. This wound bed has both yellow stringy slough as well as thick adherent slough. Slough on a wound bed should be surgically debrided to allow for ingrowth of healthy granulation tissue.
If you have dissolvable sutures, they will dissolve on their own. This may take up to 1 or 2 months. Continue to check the sutures until they're dissolved. They may look like a small piece of white string at your wound.
Slough is made up of white blood cells, bacteria and debris, as well as dead tissue, and is easily confused with pus, which is often present in an infected wound (Figs 3 and 4).