How can a lice infestation be identified? - briefly
Inspect the hair and scalp for live insects and their oval, cement‑attached eggs (nits) close to the roots, and note persistent itching or tiny red papules caused by bites. Use a fine‑toothed comb on wet hair to reveal any hidden lice or nits.
How can a lice infestation be identified? - in detail
Detecting a lice outbreak requires systematic observation and specific tools. The first step is a thorough visual examination of the scalp and hair. Use a well‑lit area or a magnifying loupe to scan for live insects, which appear as small, tan‑brown, wingless bodies moving quickly across hair shafts. Pay particular attention to the nape of the neck, behind the ears, and the crown, where lice preferentially reside.
A second indicator is the presence of nits—oval, whitish eggs firmly attached to the hair shaft within ¼ inch of the scalp. Unlike dandruff, nits do not detach easily; they must be scraped off with a fine‑tooth comb or a fingernail. A high concentration of nits, especially when several are found close together, strongly suggests an active infestation.
Third, monitor for persistent itching. The itch results from an allergic reaction to lice saliva and typically worsens several hours after a feeding session. While occasional scalp irritation can have other causes, itching that intensifies after a night’s sleep is a reliable symptom.
To confirm the diagnosis, employ a specialized lice comb. The comb’s teeth are spaced at 0.2 mm intervals, allowing it to capture both adult lice and nits. Comb the hair in sections, starting at the scalp and moving outward. After each pass, wipe the comb on a white paper towel; any captured insects become immediately visible.
If visual inspection is inconclusive, consider a laboratory analysis. Collect a few hair strands with attached debris, place them in a sealed container, and send them to a medical laboratory for microscopic examination. This method provides definitive identification of lice species and egg viability.
Finally, conduct a secondary check on close contacts—family members, classmates, or caregivers. Lice spread through head‑to‑head contact, so examining anyone who shares hats, scarves, or hair accessories can prevent re‑infestation. Use the same visual and combing techniques described above for each person.
By combining direct observation, targeted combing, symptom assessment, and, when needed, laboratory confirmation, the presence of head lice can be accurately established and addressed promptly.