A 28-year-old man is brought to the emergency department 2 hours after a flame burn injury sustained while cooking. On examination, the affected area over his right forearm and hand shows a leathery, charred appearance with a dark brown-black color. The skin is painless to touch, and there is no blanching on pressure. The surrounding area shows blistering and erythema. What is the depth classification of the burn injury on the right forearm?

Explanation

## Burn Depth Classification **Key Point:** Full-thickness burns (third-degree) involve destruction of the entire epidermis and dermis, extending into or beyond the subcutaneous tissue. ### Clinical Features of Full-Thickness Burns | Feature | Full-Thickness | Deep Partial | Superficial Partial | Superficial | |---------|---|---|---|---| | **Color** | Charred, black, brown, white, leathery | Dark red, mottled | Bright red, blistered | Pink, erythematous | | **Texture** | Leathery, hard, inelastic | Wet, glistening | Wet, glistening | Dry or slightly moist | | **Pain Response** | Painless (nerve destruction) | Painful | Very painful | Painful | | **Blanching** | No blanching | Slow/no blanching | Brisk blanching | Brisk blanching | | **Depth** | Full thickness of skin + subcutaneous | Deep dermis | Superficial to mid-dermis | Epidermis only | | **Healing** | Requires grafting | Scarring likely | Spontaneous, minimal scar | Spontaneous, no scar | **High-Yield:** The **leathery, charred appearance with painlessness and absence of blanching** are pathognomonic for full-thickness burns. The destruction of nerve endings explains the absence of pain sensation. **Clinical Pearl:** In this case, the surrounding area showing blistering and erythema represents partial-thickness burns, which is typical at the periphery of a flame burn injury where heat exposure is less intense. ### Pathophysiology Full-thickness burns result in: 1. Complete necrosis of epidermis and dermis 2. Destruction of all skin appendages (hair follicles, sweat glands, sebaceous glands) 3. Damage to sensory and motor nerve endings 4. Exposure of subcutaneous fat and muscle 5. Inability to heal spontaneously — requires skin grafting **Mnemonic: CHAR** — **C**harred appearance, **H**ard leathery texture, **A**bsent pain sensation, **R**equires grafting (for full-thickness burns). ### Clinical Significance - Full-thickness burns >10% body surface area (BSA) require referral to a specialized burn center - Escharotomy may be required if circumferential to prevent compartment syndrome - Fluid resuscitation using Parkland formula is critical - Early excision and grafting improves outcomes and reduces infection risk