How can you determine the presence of lice on the head? - briefly
Examine the hair and scalp with a fine-tooth comb, searching for live insects, nits firmly attached within a centimeter of the scalp, and localized itching. Verify any findings by close visual inspection or professional evaluation.
How can you determine the presence of lice on the head? - in detail
Detecting an infestation of head lice requires a systematic visual and tactile examination. Begin by positioning the individual in a well‑lit area, preferably using natural daylight or a bright lamp. Separate the hair into small sections, securing each with a clip or elastic band. This exposure allows close inspection of the scalp and hair shafts.
Use a fine‑tooth lice comb, ideally with teeth spaced 0.2‑0.3 mm apart. Run the comb from the scalp outward on each section, wiping the teeth on a white surface after each pass. Live insects appear as gray‑brown, wingless bodies about 2–4 mm long. Their movement is rapid; a quick flick of the comb can dislodge them for observation.
Inspect for nits, the oval, translucent eggs cemented to hair shafts. Viable nits are firmly attached within ¼ inch (6 mm) of the scalp and have a pointed end toward the root. Empty shells are translucent and may be located farther from the scalp. A magnifying glass (10×) or a handheld loupe aids in distinguishing viable nits from debris.
Additional indicators include:
- Persistent itching, especially after a few days, caused by an allergic reaction to lice saliva.
- Redness or small sores on the scalp from scratching.
- Presence of “crawlers” (young lice) moving on the hair or skin.
To confirm, repeat the combing process after 24–48 hours. A second examination often reveals lice missed during the initial search, as eggs hatch within this period. If live lice or viable nits are found in any pass, an infestation is present and treatment should commence.