In scabies, the characteristic burrow is created by which stage of the mite?

Explanation

## Burrow Formation in Scabies ### Lifecycle and Burrow Creation **Key Point:** Only gravid (pregnant) female mites create burrows in the stratum corneum; males remain on the skin surface. ### Detailed Mechanism | Stage | Location | Function | Duration | |-------|----------|----------|----------| | **Gravid female** | Stratum corneum | Creates burrow to lay eggs | 4–6 weeks lifespan | | **Male** | Skin surface | Copulation only; no burrowing | Shorter lifespan | | **Larvae & nymphs** | Skin surface or shallow follicles | Migrate, feed, develop | Days to weeks | ### Burrow Characteristics - **Appearance:** Linear, wavy, or S-shaped track in stratum corneum - **Length:** 1–10 mm (variable) - **Content:** Mite feces (scybala), eggs, and mite body parts - **Location:** Commonly on finger webs, wrists, elbows, axillae, genitalia, buttocks - **Visibility:** Best seen with dermoscopy or magnifying glass; may be obscured by secondary changes (excoriation, inflammation) **Clinical Pearl:** The burrow is pathognomonic for scabies when identified; finding even one burrow with mites on microscopy confirms diagnosis. **High-Yield:** Burrows are most numerous in the first 4–6 weeks of infection (when female mite load is highest); they may become less prominent later due to host immune response and secondary infection. [cite:Irvine Dermatology 5e Ch 12]