How can lice be eradicated from the head? - briefly
Apply an FDA‑approved pediculicide (shampoo, lotion, or mousse), leave it on for the recommended time, then remove all live insects and nits with a fine‑toothed comb; repeat the treatment after 7–10 days to eliminate any newly hatched lice. Use clean bedding, clothing, and personal items to prevent re‑infestation.
How can lice be eradicated from the head? - in detail
Eliminating head‑lice infestations requires a systematic approach that combines direct treatment of the scalp, thorough removal of eggs, and environmental decontamination.
The first step is confirmation of an active infestation. Adult lice are about 2–3 mm long, gray‑brown, and move quickly on the hair shaft. Nits appear as tiny, oval, white or yellowish structures attached firmly to the side of the hair shaft, within 1 cm of the scalp. Visual inspection using a fine‑toothed comb under bright light allows accurate identification.
Chemical pediculicides constitute the most widely used scalp treatments. Over‑the‑counter products contain either permethrin (1 %) or pyrethrin combined with piperonyl butoxide. Application follows the manufacturer’s instructions: apply to dry hair, leave for the specified time (usually 10 minutes), then rinse thoroughly. Resistance to permethrin has been reported; in such cases, prescription‑only agents such as malathion (0.5 %), benzyl alcohol lotion (5 %), ivermectin lotion (0.5 %), or spinosad (0.9 %) provide alternative mechanisms of action. All chemical treatments should be repeated after 7–10 days to eradicate newly hatched nymphs that survived the initial dose.
Physical removal complements chemical methods and is essential for eliminating viable nymphs and unhatched eggs. Wet combing with a fine‑toothed lice comb, performed on thoroughly drenched hair, dislodges lice and nits. The process involves:
- Sectioning hair into manageable portions.
- Running the comb from scalp to tip in a slow, steady motion.
- Wiping the comb on a white tissue after each pass to inspect for captured insects.
- Repeating the combing every 2–3 days for at least two weeks.
Suffocation techniques, such as applying a dense silicone‑based lotion (e.g., dimethicone) that coats the hair shaft, immobilize lice by blocking respiratory spiracles. The product remains on the scalp for several hours before washing, after which standard combing removes dead insects and eggs.
Environmental decontamination reduces the risk of re‑infestation. Items that have contacted the scalp for less than 48 hours (hats, hair accessories, pillowcases, towels) should be laundered in hot water (≥ 60 °C) and tumble‑dried on high heat. Non‑washable objects can be sealed in a plastic bag for two weeks or exposed to a dryer on high heat for 30 minutes. Vacuuming carpets, upholstered furniture, and vehicle seats eliminates any dislodged nits.
Prevention strategies limit future outbreaks. Regular head inspections in schools or childcare settings, avoidance of head‑to‑head contact, and discouragement of sharing personal items (combs, caps, headphones) are effective measures. For families with recurrent infestations, rotating between chemical classes or employing a combined chemical‑and‑wet‑comb regimen can prevent resistance development.
In summary, successful eradication of head lice relies on confirming the infestation, applying an appropriate pediculicide (or a suffocating agent) with a mandatory follow‑up dose, executing systematic wet combing, and implementing rigorous cleaning of personal and household items. Continuous monitoring for at least three weeks after treatment ensures complete resolution.