How to diagnose lice? - briefly
Examine the scalp and hair under bright light, searching for live insects and nits attached within a centimeter of the skin. Verify the finding by combing a small section with a fine‑toothed lice comb and inspecting the comb for lice or eggs.
How to diagnose lice? - in detail
Detecting a head‑lice infestation requires systematic observation and appropriate tools. Begin with a thorough visual assessment of the scalp and hair. Use a bright, magnified light source to reveal live insects and their eggs. Examine the hair close to the scalp, especially behind the ears, at the nape, and in the crown region, where nits are most likely to be attached.
A fine‑toothed lice comb, preferably with 0.2‑mm spacing, should be employed on dry hair. Run the comb from the scalp outward in small sections, wiping the teeth after each pass. Collect any captured specimens on a white tissue or foil for easier identification. Repeat the combing process at least three times over several days to account for hatching cycles.
Key visual cues include:
- Live lice: gray‑brown, wingless insects about 2–4 mm long, moving quickly.
- Nits: oval, tan or white, firmly glued to the hair shaft within ¼ inch of the scalp; the shell is translucent when empty.
- Viable nits: appear slightly larger, darker, and may contain a visible embryo.
Differentiating nits from dandruff or hair spray residue is essential. Dandruff is loosely attached and easily dislodged, while nits remain fixed despite gentle pulling. Examine any suspect egg under magnification; a viable nit shows a convex, smooth surface, whereas an empty shell is flattened and brittle.
If visual confirmation is uncertain, a microscopic examination can be performed. Collect a sample of hair and nits, place them on a slide, and observe at 40–100× magnification. Live lice exhibit active legs and antennae; nits reveal embryonic development stages.
Document findings with photographs when possible, noting the location and quantity of lice and nits. Record the date of inspection to schedule follow‑up examinations, typically 7–10 days later, to ensure that newly hatched insects are detected and treated promptly.