How can one tell that the lice are head lice? - briefly
Head lice are identified by their presence on the scalp or hair of the head, appearing as tiny, gray‑white insects that move quickly and lay nits firmly attached to hair shafts within a millimeter of the scalp. Unlike other lice, they do not infest clothing, bedding, or other body parts, and their eggs are unmistakably cemented to the hair near the roots.
How can one tell that the lice are head lice? - in detail
Head lice are small, wing‑less insects that live on the scalp and feed on blood. Recognizing them requires careful visual inspection and awareness of their distinguishing features.
First, examine the hair close to the scalp, especially behind the ears and at the nape of the neck. Live lice appear as gray‑brown, oval bodies about 2–4 mm long. Their heads are narrower than their abdomens, and they move actively when disturbed. Nymphs, which are immature lice, look similar but are smaller and lack egg shells.
Second, look for nits—lice eggs—attached to hair shafts. Nits are oval, about 0.8 mm in length, and have a firm, chalky appearance. They are firmly glued to the strand within ¼ inch (6 mm) of the scalp; this proximity indicates that the eggs are viable. Unhatched nits farther from the scalp are often older and may be empty.
Third, note the presence of itching or a crawling sensation on the scalp. This symptom results from an allergic reaction to louse saliva and is a reliable clinical clue.
Key criteria for confirmation:
- Live insects visible on the scalp, especially near the hairline, behind ears, or at the back of the neck.
- Nits firmly attached within 6 mm of the scalp, with a translucent or white coloration.
- Recent or ongoing itching, often worsening after heat exposure (e.g., showering).
- Absence of wings; lice cannot jump, only crawl.
If these elements are observed together, the infestation can be confidently identified as head lice rather than other parasites such as crab lice (pubic lice) or dandruff. Accurate identification enables prompt treatment and prevents further spread.