How can I tell that I have lice on my head? - briefly
Examine the scalp and hair for live lice—tiny, grayish‑brown insects about the size of a sesame seed—and for nits, which appear as oval, white or tan shells attached within a millimeter of the scalp. Persistent itching or the presence of these signs confirmed with a fine‑toothed lice comb indicates an infestation.
How can I tell that I have lice on my head? - in detail
Head lice infestations reveal themselves through several observable signs. The most reliable indicator is the presence of live insects crawling on the scalp or hair shafts. Adult lice are about the size of a sesame seed, grayish‑white, and move quickly when the hair is brushed or the head is examined under bright light.
A secondary symptom is persistent itching, caused by an allergic reaction to lice saliva. The itch intensifies several days after the infestation begins, because the nervous system becomes sensitized. Scratching may leave small red or irritated spots on the scalp, but itching alone does not confirm an infestation.
The most definitive evidence consists of nits—lice eggs firmly attached to the hair shaft. Nits appear as tiny, oval, yellow‑to‑white structures, typically located within a half‑inch of the scalp. Because they are glued to the hair, they do not slide down when the hair is moved. A nit that is easily dislodged is likely a shed egg or a false positive; a firmly attached nit confirms the presence of lice.
To verify an infestation, follow these steps:
- Part the hair into small sections, using a fine‑toothed comb or a lice detection comb.
- Examine each section under a well‑lit area or a magnifying glass.
- Look for live lice moving quickly along the hair shaft or clinging to the scalp.
- Search for nits within ¼ inch of the scalp; note their color and attachment strength.
- Check behind the ears, at the nape of the neck, and along the hairline, where lice commonly congregate.
- Record the number of live insects and firmly attached nits; a count of several live lice or multiple attached nits confirms an infestation.
If live lice are observed, the infestation is active. If only nits are found, the situation may be an early or declining infestation; a second inspection after 7–10 days can reveal newly hatched lice. Regular monitoring for 2–3 weeks ensures that any remaining eggs hatch and are detected before they mature.