How to identify lice on a person's head? - briefly
Inspect the scalp and hair for tiny, oval, white or yellowish nits firmly glued to strands within a quarter‑inch of the skin, and for live insects about the size of a sesame seed that move quickly when disturbed. Use a fine‑toothed comb on wet, conditioned hair to confirm their presence by catching the parasites or their eggs.
How to identify lice on a person's head? - in detail
Detecting an infestation of head‑dwelling insects requires systematic visual inspection and tactile confirmation. Begin by preparing a bright, magnified light source and a fine‑toothed comb designed for lice detection. Separate the hair into small sections, preferably 1‑2 cm wide, and comb from scalp outward. Examine the comb teeth after each pass; live insects appear as gray‑brown, wingless bodies about 2–4 mm long, with six legs. Nymphs are smaller, translucent, and move quickly when disturbed.
Key visual cues include:
- Live specimens: active movement, shape resembling a tiny crab, often found close to the scalp where temperature is highest.
- Eggs (nits): oval, 0.8 mm, firmly attached at a 45‑degree angle to the hair shaft, usually within 1 cm of the scalp. The cement-like substance makes them difficult to slide off; a gentle pull will not detach them.
- Brown or black specks: may be dead lice or shed exoskeletons; these do not indicate current infestation but confirm prior presence.
Confirmatory steps:
- Wet‑comb method: Apply a small amount of conditioner to the hair, comb thoroughly, and rinse the comb on white paper. Live lice will be visible; nits remain attached to hair.
- Magnification: Use a hand lens (×10) to distinguish nits from dandruff. Dandruff is loosely attached and falls off easily, whereas nits remain fixed.
- Scalp examination: Look for redness, itching, or small raised bumps (papules) caused by bites. Persistent scratching may lead to secondary infection, indicating a need for treatment.
Avoid misidentification by noting that lice require a live host and cannot survive more than 24 hours off the scalp. Dandruff, seborrheic flakes, or hair debris do not exhibit the firm attachment angle characteristic of eggs. A thorough inspection of the entire scalp, including behind the ears and at the nape, ensures no area is overlooked.