How can you tell that lice are in a person's head? - briefly
Persistent scalp itching, especially after a few days, usually indicates an infestation. Examine the hair closely for tiny, white, oval nits attached to strands near the scalp and for live, grayish insects that move quickly.
How can you tell that lice are in a person's head? - in detail
Lice infestations on the scalp can be recognized through direct observation and physical symptoms.
The adult parasite measures 2–4 mm, is tan‑brown, and moves quickly across hair shafts. Nits (eggs) appear as tiny, oval, white or yellowish structures firmly attached to the base of each hair strand, typically within ¼ inch of the scalp. Because nits are cemented to the hair, they do not slide easily when the hair is brushed.
Common indicators include:
- Persistent itching, especially after a few days, caused by an allergic reaction to lice saliva.
- Small, dark specks (fecal matter) on the scalp or clothing, often mistaken for dandruff.
- Visible live insects or nits during a thorough visual inspection, best performed with a fine‑toothed lice comb on wet, conditioned hair.
Effective detection steps:
- Wet the hair, apply a generous amount of conditioner, and comb from the scalp outward, wiping the comb after each pass.
- Examine each comb tooth for live lice, nymphs, or attached eggs.
- Use a magnifying glass if necessary to differentiate nits from hair debris; true nits are attached at a 45‑degree angle to the hair shaft.
- Inspect the neck, behind the ears, and at the hairline, as these areas are common hiding spots.
If live lice or multiple nits are found, the infestation is confirmed and treatment should begin promptly. Absence of these signs after multiple combings suggests no active infestation.