EscharEdit

Eschar is a dry, dark, adherent crust that forms over a wound or burned area as necrotic tissue and dried exudate consolidate. It is distinct from a simple crust or scab formed during normal healing, in that eschar is often firmly attached and can represent substantial tissue death. Clinically, the presence of eschar helps gauge tissue viability, the depth of injury, and the risk of infection. Understanding eschar is essential for decisions in acute care and follow-up wound management, including whether to pursue debridement or other interventions.

Although eschar is most commonly discussed in burn care, it also occurs with frostbite, pressure ulcers, and certain surgical wounds. In burns, circumferential eschar can act like a constrictive tourniquet, compromising perfusion and sometimes necessitating procedures such as an escharotomy to relieve pressure and restore circulation. Management of eschar blends immediate clinical action with ongoing wound care, aiming to prevent infection, minimize scarring, and promote functional recovery, all within the context of a patient’s overall health, nutrition, and comorbidities such as diabetes.

Definition and terminology

Eschar vs crust: Eschar is a firmly adherent, necrotic tissue crust, whereas a crust or scab from routine healing is typically looser and part of a normal healing process.
Adherence and perfusion: The firmness and coverage of eschar can affect adjacent tissue perfusion and tissue viability, informing the urgency of intervention.
Terminology often used in practice includes references to burn eschar, frostbite eschar, and ischemic eschar from pressure ulcers, each with its own management nuances. See Burn (injury) and Frostbite for broader context, and Ischemia for the perfusion concepts involved.

Formation and clinical features

Pathophysiology: Eschar forms when tissue undergoes necrosis and coagulation of proteins creates a dense, protective crust that adheres to underlying tissue.
Appearance: It typically appears dark brown to black, may be dry or crusty, and often lies over areas with significant tissue damage. In some wounds, eschar can be surrounded by viable tissue that is healing or already re-epithelializing.
Associated risks: The presence of eschar correlates with higher risk of infection, delayed healing, and, in burns, potential progression of tissue loss if perfusion remains compromised.

Contexts and etiologies

Thermal burns: Eschar is common after moderate to severe thermal injuries. Circumferential burns, in particular, can produce tight eschar that restricts chest wall or limb movement and blood flow.
Chemical burns and irradiated skin: These injuries can produce extensive necrosis and eschar formation, complicating healing.
Frostbite: Deep frostbite injuries can develop eschar as tissue in the zone of stasis or necrosis evolves.
Pressure ulcers: In prolonged pressure holding tissue in place, ischemic necrosis can culminate in an eschar over bony prominences.
Surgical wounds: Some surgical sites develop postoperative eschar, especially when local tissue perfusion is compromised or when dressings create moisture and occlusion that favors necrotic crust formation.

Diagnosis and management

Assessment: Clinicians evaluate wound depth, perfusion, signs of infection, and the extent of necrotic tissue. Imaging or evaluation of surrounding tissue helps determine whether eschar is limiting recovery.
Debridement: Removal of eschar is a central management option when it hinders healing or threatens perfusion. Techniques include sharp debridement, enzymatic debridement, autolytic methods, and, in some cases, maggot debridement therapy Maggot debridement therapy.
Escharotomy: In circumferential burns, where eschar constricts the chest or limb, an escharotomy may be performed to restore ventilation or circulation.
Wound care: After debridement, wound care involves dressings, infection prevention, and measures to promote revascularization and re-epithelialization. Materials such as hydrogel, hydrocolloid, alginate, and moisture-retentive dressings may be used, along with approaches to pain management and tetanus prophylaxis.
Infection control: Eschar can harbor bacteria; careful monitoring for signs of infection and appropriate antibiotic use when indicated are important considerations.
Healing trajectory: The presence of eschar, comorbidities, nutritional status, and wound location all influence the healing timeline and the likelihood of scar formation or functional recovery.

Pathophysiology and prognosis

Tissue viability: Eschar reflects tissue that has lost viability; surrounding tissue may remain viable and contribute to eventual healing after necrotic tissue is removed.
Prognosis: Larger areas of necrosis, significant comorbidities (e.g., diabetes, vascular disease), and delays in treatment can worsen prognosis, increase the risk of infection, and prolong recovery.

Historical and practical notes

Historical perspective: The understanding and management of eschar evolved with advances in burn care, wound management, and surgical techniques. Early observers recognized that necrotic crusts impeded healing and could signal deeper injury.
Practical considerations: The decision to debride and the choice of debridement technique depend on factors such as wound depth, infection risk, patient stability, and available clinical resources.

Controversies and debates (from a practical, policy-aware perspective)

Timing of debridement: Debridement too early or too aggressively can risk damage to viable tissue, while delaying debridement can allow infection and necrosis to progress. Evidence supports tailored timing based on wound characteristics, perfusion, and patient status, with some favoring earlier intervention in heavily necrotic tissue and others advocating staged approaches in high-risk patients.
Debridement methods: Sharp debridement provides rapid removal of necrotic tissue but requires skilled clinicians and carries risks of bleeding and pain. Enzymatic and autolytic methods are less invasive but slower. Maggot therapy can be effective in certain chronic wounds but may face acceptance issues among patients and clinicians who favor traditional methods.
Access and innovation: Public and private investment in burn centers and specialized wound care facilities can affect outcomes. Critics of heavy government budgeting for specialized care argue for targeted funding that prioritizes rapid access to high-quality care, prevention programs, and research, while defenders emphasize the societal value of comprehensive, universally accessible burn care and wound treatment.
Regulation and devices: Debridement and wound-care technologies intersect with regulatory oversight and device approvals. A consistent emphasis on evidence-based practice supports standardized protocols, while proponents of innovation argue for streamlined pathways that allow new, effective devices and methods to reach patients more quickly.
Public health framing: While prevention and rapid treatment are central, debates exist about how to balance public health mandates with individual responsibility in wound care, nutrition, diabetes management, and exposure to injury risks. The broader conversation often centers on funding and organizational structure for emergency and acute care versus incentives for private providers and market-based solutions.