What do lice look like on hair and how are they treated? - briefly
Adult head lice are about the size of a sesame seed, gray‑brown, with six legs and a body that grips hair shafts; nymphs are smaller but share the same coloration. Effective control uses a pediculicide shampoo or lotion applied to the scalp, followed by meticulous nit‑combing, and a repeat treatment after 7–10 days to eradicate newly hatched insects.
What do lice look like on hair and how are they treated? - in detail
Head lice are small, wingless insects about 2–4 mm long. The adult body is flattened, oval, and grayish‑brown. Six legs end in claw‑like tarsi that grip individual hair shafts near the scalp. Nymphs resemble miniature adults, differing only in size and color, which is lighter until they molt. Eggs, called nits, appear as tiny, oval, white or yellowish shells cemented to the hair cuticle about 1 mm from the scalp; they are firmly attached and cannot be brushed off easily.
Identification relies on visual inspection of the scalp and hair. Live insects move quickly, often found behind the ears, at the nape, or along the hairline. Nits are distinguishable from dandruff by their fixed position and the presence of a brown dot at the base, indicating a developing embryo. A magnifying lens or handheld loupe improves detection accuracy.
Treatment proceeds in two phases: eradication of the insects and prevention of reinfestation.
- Chemical pediculicides – FDA‑approved shampoos, lotions, or sprays containing 1 % permethrin, 0.5 % pyrethrin, or 0.5 % malathion. Apply to dry hair, leave for the manufacturer‑specified time, then rinse. Repeat after 7–10 days to kill newly hatched nymphs.
- Prescription oral agents – ivermectin or dimethicone tablets for cases resistant to topicals. Dosage follows medical guidelines; monitor for side effects.
- Mechanical removal – fine‑toothed combs (nylon, metal, or silicone) used on wet, conditioned hair. Comb from scalp outward every 2–3 days for two weeks, discarding collected debris after each pass.
- Environmental decontamination – wash bedding, hats, and clothing in hot water (≥ 60 °C) or seal items in plastic bags for 48 hours. Vacuum carpets and upholstered furniture; avoid sharing personal items.
- Follow‑up inspection – re‑examine hair after treatment cycle; any remaining nits must be removed manually. Persistent infestation warrants a second course of a different pediculicide or consultation with a healthcare professional.
Combining chemical application with diligent combing and environmental measures yields the highest success rate, typically eliminating the infestation within three weeks. Maintaining regular scalp checks, especially in communal settings such as schools, reduces the likelihood of recurrence.