What do lice look like and how can they be removed? - briefly
Lice are tiny, wing‑less insects about 2–4 mm long, gray‑white to brown, with a flattened body and six legs that grip hair shafts. Effective removal involves applying a permethrin‑ or dimethicone‑based shampoo or lotion, combing with a fine‑toothed nit comb, and repeating the process after 7–10 days to eliminate newly hatched nits.
What do lice look like and how can they be removed? - in detail
Lice are tiny, wing‑less insects measuring 2–4 mm in length. Their bodies are flattened laterally, facilitating movement through hair shafts. The head is broader than the thorax, with six legs ending in sharp claws that grip each strand of hair. Color ranges from gray‑white to brown, often appearing translucent when unfed and darker after a blood meal. Live lice are mobile, moving quickly up and down the scalp; dead specimens remain stationary and may be mistaken for dandruff.
Adult females lay 6–10 eggs (nits) per day, attaching them firmly to the hair shaft within 1 mm of the scalp. Nits are oval, about 0.8 mm long, and have a glossy, white appearance. The shell is cemented with a proteinaceous substance, making it difficult to dislodge without specialized tools. Eggs hatch in 7–10 days, releasing nymphs that resemble miniature adults and mature within 9–12 days.
Effective eradication combines chemical, mechanical, and environmental strategies:
- Topical pediculicides: FDA‑approved products containing permethrin (1 %) or pyrethrin with piperonyl butoxide. Apply to dry hair, leave for the recommended duration (usually 10 minutes), then rinse thoroughly. Repeat treatment after 7 days to target newly hatched nymphs.
- Dimethicone‑based lotions: Silicone oils that coat lice, obstructing respiration. Leave on hair for 10–15 minutes, then comb out. No resistance reported.
- Manual removal: Use a fine‑toothed nit comb on wet, conditioner‑treated hair. Comb from scalp to tip in 1‑inch sections, wiping the comb after each pass. Perform daily for at least 10 days.
- Heat treatment: Apply a calibrated hair dryer (≥ 130 °C) to sections of hair for 30 seconds, sufficient to kill lice without damaging scalp tissue. Requires precise temperature control.
- Environmental decontamination: Wash clothing, bedding, and towels in hot water (≥ 60 °C) and dry on high heat for at least 30 minutes. Items that cannot be laundered should be sealed in a plastic bag for 2 weeks.
Monitoring after treatment involves inspecting the scalp every 2–3 days for live insects or viable nits. Any remaining nits should be removed with the nit comb; live lice indicate treatment failure and may require an alternative pediculicide or professional consultation. Continuous vigilance for at least 4 weeks prevents reinfestation.