Eschar vs. Necrotic Tissue: Key Differences
Eschar is a specific type of necrotic tissue characterized by thick, leathery, dry, black or brown dead tissue that forms a hardened covering over a wound, while necrotic tissue is a broader term encompassing all dead tissue including eschar, slough, and other forms of devitalized tissue. 1
Defining Characteristics
Eschar
- Appearance: Thick, leathery, dry, adherent black or brown tissue that forms a hardened crust over the wound 1, 2
- Texture: Firm and rigid, often requiring crosshatching with a blade to allow topical agents better surface contact 3
- Location: Commonly forms on heels, burn wounds, and areas with full-thickness tissue loss 1, 2, 4
- Function: Can serve as a natural biological cover in certain circumstances, particularly when stable and dry 1, 2
Necrotic Tissue (General)
- Broader category: Includes eschar, slough (yellow/tan soft tissue), and any devitalized tissue 1, 5
- Variable appearance: Can be wet or dry, soft or hard, yellow, tan, brown, or black 1
- Consistency: Ranges from liquefied to firm depending on the type and stage 6
Clinical Management Differences
When to Leave Eschar in Place
For stable, dry, adherent eschar—especially on the heel—it is preferable to leave it in place until it softens enough for easier removal, provided there is no underlying infection. 1, 2 This approach is particularly appropriate for:
- Patients who are poor surgical candidates 1
- Dry gangrene where auto-amputation is preferred 1
- Heel eschars without signs of infection 1, 2
When to Remove Necrotic Tissue/Eschar
Debridement is necessary when: 1, 5
- Evidence of underlying infection (erythema, warmth, purulent drainage, odor) 2
- The eschar begins to soften and loosen 2
- Bacterial colonization risk is high (burn wounds) 1
- Assessment of wound depth is needed 2
- Granulation tissue formation is impaired 1
Treatment Approaches
Sharp Debridement
- Preferred method for both eschar and necrotic tissue when removal is indicated 1
- More definitive and controllable than other techniques 1, 2
- May require crosshatching thick eschar before applying enzymatic agents 3
- Should be repeated as often as needed if nonviable tissue continues to form 1
Enzymatic Debridement
- Collagenase ointment can be applied to eschar after crosshatching to increase surface contact 3
- Bromelain-based agents effectively remove burn eschar in a single application 7
- Useful when sharp debridement is contraindicated or impractical 3, 7
Autolytic Debridement
- Hydrogels: Facilitate autolysis of dry or necrotic wounds and help soften eschar 1, 2
- Hydrocolloids: Absorb exudate and facilitate autolysis 1, 2
- Slower but less invasive than sharp debridement 2
- May not be effective for thick, leathery eschar 8
Critical Pitfalls to Avoid
Ischemic Wounds
Debridement may be relatively contraindicated in primarily ischemic wounds. 1, 2 Before aggressive debridement:
- Assess arterial perfusion (palpate dorsalis pedis and posterior tibial pulses) 9
- Refer to vascular specialist if limb appears ischemic 1, 2
- Consider revascularization before extensive debridement 1
Premature Removal
- Avoid premature removal of stable, dry eschar, especially on the heel, as this can cause unnecessary tissue damage 9, 2
- Allow demarcation between viable and nonviable tissue to become clear in nonsevere infections 1
Infection Recognition
The absence of fever or leukocytosis should not dissuade consideration of underlying infection. 1 Monitor for:
- New onset wound anesthesia 1
- Pain out of proportion to clinical findings 1
- Dorsal erythema or fluctuance with plantar wounds (suggests deep infection) 1
- Failure to improve with appropriate therapy 1
Burn Wound Eschar
Early excision of burn eschar substantially decreases the incidence of invasive burn wound infection. 1 Burn eschar: