How can you determine if a person has lice on their head? - briefly
Examine the scalp and hair closely for live insects the size of sesame seeds or for oval, yellow‑white eggs (nits) attached within a quarter inch of the scalp, using a fine‑tooth comb on wet hair. Feeling movement or crawling when the hair is brushed confirms an infestation.
How can you determine if a person has lice on their head? - in detail
To confirm the presence of head‑lice, follow a systematic examination that combines visual observation, tactile assessment, and, if needed, laboratory verification.
First, conduct a thorough visual scan of the scalp and hair. Look for live insects measuring 2–4 mm, grayish‑brown in color, with six legs. Pay special attention to the nape of the neck, behind the ears, and the crown—areas where lice preferentially settle. Notice any small, oval, white or yellowish structures attached to hair shafts; these are nits, the eggs of the parasite. Nits are firmly cemented to the strand and lie within 1 cm of the scalp. Their shells are translucent when newly laid and become opaque as they mature.
Second, perform a tactile check. Run a fine‑toothed lice comb (spacing 0.2–0.4 mm) through damp, conditioned hair from the scalp outward. After each pass, wipe the comb on a white tissue or rinse it in a container of water. Live lice will appear as moving specks; nits will remain attached to the comb. Repeat the process several times, covering the entire head, to increase detection sensitivity.
Third, assess secondary symptoms. Persistent itching, especially after a night’s sleep, often indicates an allergic reaction to lice saliva. Secondary signs include excoriations, redness, or small, inflamed papules. Distinguish these from dandruff or seborrheic dermatitis, which lack attached nits and do not produce moving insects.
If uncertainty remains, collect a few suspect specimens and examine them under a light microscope at 40–100× magnification. Live lice exhibit characteristic body segmentation and active movement; nits display a characteristic operculum at one end.
For confirmation in institutional settings, an adhesive‑tape test can be employed. Press clear medical tape to the scalp, lift it, and inspect the tape under magnification for attached lice or nits.
By integrating visual inspection, combing technique, symptom evaluation, and optional microscopic verification, one can reliably determine whether an individual is infested with head‑lice.