How to kill a louse in hair? - briefly
Use an over‑the‑counter pediculicide shampoo or lotion containing 1 % permethrin or 0.5 % pyrethrin, apply according to the product instructions, then comb out dead insects with a fine‑toothed nit comb. Follow with a second treatment in 7–10 days to eliminate any newly hatched lice.
How to kill a louse in hair? - in detail
Eliminating a head‑louse infestation requires a systematic approach that combines direct treatment of the scalp, thorough combing, and environmental sanitation.
First, select an appropriate pediculicide. Over‑the‑counter products containing 1 % permethrin or 0.5 % pyrethrin are effective when applied to dry hair, left for the recommended duration (usually 10 minutes), then rinsed thoroughly. For resistant cases, a prescription‑only lotion with 0.05 % malathion or 0.2 % spinosad may be necessary; follow the clinician’s instructions precisely to avoid toxicity.
Second, perform mechanical removal. After the chemical agent has dried, use a fine‑toothed nit comb on damp hair. Work from the scalp outward, sectioning the hair and combing each strand at least five times. Discard each combed segment on a white surface to verify that no live insects remain. Repeat the combing process at 7‑day intervals for two successive weeks to catch any newly hatched nymphs.
Third, consider non‑chemical alternatives when sensitivity or preference dictates. Apply a mixture of 20 % dimethicone to the hair, cover with a shower cap for 30 minutes, then rinse. The silicone coating suffocates the parasites without affecting the host. Essential‑oil solutions (e.g., 1 % tea‑tree oil) may reduce infestation severity but should be used with caution, as they can cause scalp irritation.
Fourth, address the surrounding environment. Wash all bedding, towels, and clothing used within the previous 48 hours in water ≥ 60 °C, then tumble‑dry on high heat for at least 30 minutes. Items that cannot be laundered should be sealed in a plastic bag for two weeks, a period exceeding the louse life cycle. Vacuum carpets, upholstery, and car seats to remove detached eggs.
Fifth, monitor for treatment failure. Persistent itching after two weeks, or detection of live lice on repeat examinations, indicates the need for a second‑line agent or combination therapy. Consulting a healthcare professional ensures proper diagnosis and prevents reinfestation.
By adhering to this protocol—selecting an effective topical, executing meticulous combing, employing alternative suffocants when appropriate, sanitizing personal items, and conducting follow‑up checks—complete eradication of head lice can be achieved.