Which clinical feature best distinguishes a deep partial-thickness burn (3rd degree equivalent) from a superficial partial-thickness burn (2nd degree)?

Explanation

## Discriminating Feature Between Partial and Full-Thickness Burns ### Depth Classification Overview Burn depth determines healing potential, infection risk, and need for grafting. The key discriminator between deep partial-thickness (previously called 3rd degree) and superficial partial-thickness (2nd degree) is the extent of dermal destruction and loss of skin appendages. ### Comparison Table: Burn Depth Features | Feature | Superficial Partial (2°) | Deep Partial/Full (3°–4°) | | --- | --- | --- | | **Appearance** | Blistered, moist, pink-red | Leathery, charred, white/brown eschar | | **Blanching** | Blanches with pressure | Non-blanching | | **Skin appendages** | Partially preserved | Completely destroyed | | **Pain sensation** | Intact, very painful | Absent (nerve destruction) | | **Healing** | Epithelialization from margins & appendages (2–3 weeks) | Requires grafting; cannot heal by epithelialization | | **Scarring** | Minimal | Severe contracture and hypertrophic scarring | ### Key Point: **Complete loss of skin appendages (hair follicles, sweat glands, sebaceous glands) with a leathery, non-blanching eschar is the hallmark of deep partial-thickness and full-thickness burns.** This indicates destruction beyond the dermis and means the wound cannot heal by epithelialization from residual appendages. ### Clinical Pearl: **Non-blanching erythema or eschar** is the most reliable bedside sign of full-thickness injury. In superficial partial-thickness burns, the wound still blanches because viable dermal tissue remains. ### High-Yield: **Skin appendages are the source of epithelialization in partial-thickness burns.** Once they are destroyed, the wound requires skin grafting. This is why deep partial-thickness burns are often managed as full-thickness injuries. ### Mnemonic: **LEATHERY = LOST appendages** — A leathery, non-blanching eschar means loss of all dermal structures, including hair follicles and sweat glands.