What do lice and nits look like on a person? - briefly
Adult head lice measure roughly 2–4 mm, have a gray‑brown body, and move swiftly across the scalp; nits are tiny (about 0.8 mm), oval, yellow‑white or brownish shells that cling tightly to hair shafts near the scalp.
What do lice and nits look like on a person? - in detail
Adult head lice are small, wingless insects measuring 2–3 mm in length. Their bodies are flattened laterally, facilitating movement through hair shafts. Color varies from gray‑brown to darker brown, often appearing translucent when unfed. Six legs end in claw‑like tarsi that grip individual strands. Mobility is evident as the insects crawl rapidly, occasionally dropping when disturbed.
Nits, the eggs of the parasite, differ markedly from the adult form. Each nit measures about 0.8 mm, resembling a tiny, oval capsule. The shell is rigid, initially pale‑white, then turning yellow‑brown as the embryo develops. Nits are firmly cemented to the hair shaft, typically within 1 cm of the scalp where temperature supports incubation. The attachment point appears as a small, smooth bulge on the hair surface; the egg’s operculum (cap) is visible at one end, often slightly protruding.
Key visual indicators:
- Size: lice ≈ 2–3 mm; nits ≈ 0.8 mm.
- Color: lice = gray‑brown to dark brown; nits = white → yellow‑brown.
- Shape: lice = flattened, elongated; nits = oval, smooth.
- Location: lice = moving on scalp, behind ears, at nape; nits = attached close to scalp, aligned along hair shaft.
- Attachment: nits are glued with a sticky secretion, resistant to removal without specialized combing.
Observation of live lice requires close inspection, often with a magnifying device, as they may blend with hair. Nits remain visible after the insects die, serving as a reliable diagnostic sign.