How can you poison lice and nits? - briefly
Use a topical pediculicide—e.g., 1 % «permethrin» or 0.5 % «malathion»—apply to the hair, leave for the specified contact time, then rinse; afterwards comb with a fine‑toothed nit comb to eliminate remaining eggs.
How can you poison lice and nits? - in detail
Effective eradication of head‑lice infestations relies on agents that disrupt the nervous system of the insect or physically impair its ability to breathe. Synthetic pyrethroids, such as permethrin 1 % or phenothrin 0.5 %, bind to voltage‑gated sodium channels, causing paralysis and death. Application requires thorough saturation of hair and scalp, a minimum exposure time of ten minutes, and a repeat dose after nine days to target newly hatched nits. Resistance to pyrethroids has been documented; in such cases, organophosphates like malathion 0.5 % may be employed, acting as acetylcholinesterase inhibitors. Spinosad 0.9 % provides an alternative neurotoxic mechanism, interfering with nicotinic acetylcholine receptors.
Silicone‑based products, notably dimethicone 4 % lotion, coat lice and nits, obstructing spiracular openings and leading to desiccation. Unlike neurotoxic compounds, dimethicone exhibits low systemic absorption, making it suitable for children over six months. Application involves saturating hair, allowing a 10‑minute contact period, and combing with a fine‑toothed nit comb to remove detached insects and eggs.
Plant‑derived extracts demonstrate variable efficacy. Tea‑tree oil at 5 % concentration exerts repellent and insecticidal effects by disrupting membrane integrity. Neem seed oil, formulated at 2 % in a carrier base, interferes with molting hormones, reducing hatch rates. Both agents require multiple applications at 48‑hour intervals and thorough mechanical removal of nits.
Combing remains a critical component of any treatment regimen. A metal nit comb, used after each application, extracts live lice and empty shells, preventing re‑infestation. Re‑treatment after seven to ten days eliminates any nymphs that escaped the initial dose. Environmental decontamination—washing bedding, hats, and clothing at ≥ 60 °C, sealing non‑washable items in airtight bags for two weeks—reduces the risk of reinvasion.
Safety considerations include age‑specific restrictions: pyrethroids are contraindicated for infants under two months; malathion is unsuitable for pregnant individuals. Dimethicone presents minimal dermal irritation, while essential‑oil formulations may provoke allergic reactions; patch testing is advisable. Monitoring for adverse effects and adhering to label instructions ensures optimal outcomes while minimizing health risks.