A burn victim shows a wound with a hard, inelastic, charred eschar that does not blanch on pressure and is surrounded by a zone of hyperemia. What is the burn depth classification?

Explanation

## Clinical Diagnosis of Full-Thickness Burns **Key Point:** The clinical hallmark of a full-thickness burn is a hard, leathery, charred eschar that does NOT blanch with pressure. This indicates complete destruction of the epidermis and dermis. ### Jackson's Zones of Burn Injury Burn wounds have three concentric zones: 1. **Zone of Coagulation (Central)** — irreversible tissue death; appears charred and black 2. **Zone of Stasis (Middle)** — area of potential reversibility; hyperemic and edematous 3. **Zone of Hyperemia (Outer)** — viable tissue with inflammatory response; red and blanching In full-thickness burns, the central zone extends through the entire dermis into subcutaneous tissue. ### Clinical Features Distinguishing Burn Depths | Feature | 1st Degree | 2nd Degree | 3rd Degree | 4th Degree | |---|---|---|---|---| | **Appearance** | Red, blanching | Blistered, moist | Charred, leathery, black | Charred muscle/bone | | **Blanching** | Yes | Yes | **No** | No | | **Pain** | Severe | Severe | Painless | Painless | | **Eschar** | None | None | Hard, inelastic | Extends to muscle/bone | | **Healing** | Spontaneous | Spontaneous or grafting | Requires grafting | Amputation | **High-Yield:** The **non-blanching, hard eschar** is the single most important clinical sign of full-thickness burn. This indicates coagulation necrosis of the entire dermis with loss of dermal blood flow. **Clinical Pearl:** Full-thickness burns are painless because all nerve endings are destroyed. Surrounding hyperemia (zone of stasis) is red and may blanch — this is the area where intervention can prevent progression to full-thickness injury. **Mnemonic:** **CHEF** — **C**harred, **H**ard, **E**schar, **F**ull-thickness (and non-blanching).