How to kill lice on a person? - briefly
Apply a pediculicide shampoo or lotion with 1 % permethrin (or a comparable FDA‑approved product), leave it on for the recommended time, then comb out nits with a fine‑toothed comb; repeat the treatment after 7–10 days to eradicate any newly hatched lice.
How to kill lice on a person? - in detail
Eliminating head‑lice infestations requires a systematic approach that combines direct treatment of the scalp, thorough removal of eggs, and environmental decontamination.
First, confirm the presence of live insects or viable nits attached within ¼ inch of the hair shaft. Use a fine‑toothed lice comb on dry hair, inspecting each section under adequate lighting. If live lice are observed, initiate treatment promptly.
Chemical pediculicides are the most common option. Over‑the‑counter preparations containing 1 % permethrin or pyrethrins with piperonyl‑butoxide should be applied to dry hair, following the product’s instructions regarding dosage, exposure time (typically 10 minutes), and rinsing. Repeat the application after 7–10 days to target newly hatched nymphs that survived the first dose. Prescription agents such as 0.5 % malathion, 5 % benzyl alcohol lotion, or oral ivermectin may be used when resistance to OTC formulas is suspected; these require a medical prescription and adherence to specific dosing schedules.
Mechanical removal complements chemical treatment. After applying the chosen product, comb the hair with a fine lice comb at 5‑minute intervals for at least 30 minutes. This process dislodges live insects and extracts viable nits. Perform the combing session daily for a week, then every other day for an additional week to ensure complete eradication.
Alternative non‑chemical methods include:
- Wet combing: saturate hair with water and conditioner, then comb every 2–3 days for 10–14 days.
- Dimethicone‑based lotions: coat the hair shaft, suffocating the parasites; leave on for the recommended duration and repeat after 7 days.
- Heat treatment: use a calibrated hair dryer on a low‑heat setting while combing, avoiding scalp burns.
Environmental control prevents re‑infestation. Wash clothing, bedding, and towels used within the previous 48 hours in hot water (≥ 60 °C) and dry on high heat. Items that cannot be laundered should be sealed in a plastic bag for two weeks or placed in a freezer at −20 °C for at least 24 hours. Vacuum carpets, upholstered furniture, and car seats to remove stray nits; discard vacuum bags immediately.
Finally, monitor the scalp for two weeks after treatment. If live lice reappear, repeat the chemical regimen or switch to an alternative agent. Persistent infestations may indicate resistance, necessitating professional medical evaluation.