How should lice be treated in adults and children? - briefly
Apply a 1 % permethrin or 0.5 % malathion lotion to dry hair, leave for the recommended duration, rinse, and repeat after 7–10 days; for resistant infestations, oral ivermectin or spinosad lotion may be employed. Wash clothing and bedding at ≥50 °C, vacuum the environment, and use a fine‑tooth comb to remove nits from all affected persons.
How should lice be treated in adults and children? - in detail
Effective management of lice infestations in both adults and children requires a systematic approach that includes accurate diagnosis, appropriate pharmacologic or mechanical treatment, and environmental decontamination.
Diagnosis relies on visual inspection of the scalp and hair. Live lice are identified by their movement; nits attached within 1 cm of the scalp indicate active infestation. Absence of live insects suggests past infestation and may not require treatment.
Pharmacologic options fall into two categories: topical pediculicides and oral agents.
- Topical pediculicides: Permethrin 1 % cream rinse, pyrethrins combined with piperonyl butoxide, and dimethicone‑based lotions are first‑line choices. Application follows product instructions, typically leaving the solution on the scalp for 10 minutes before rinsing. Repeat treatment after 7–10 days eliminates newly hatched lice.
- Oral ivermectin: Single dose of 200 µg/kg body weight, repeated after 7 days, offers an alternative for resistant cases or when topical treatment is impractical. Contraindicated in pregnant or lactating women and children weighing less than 15 kg.
Mechanical removal supplements chemical therapy. Fine‑toothed lice combs, used on wet, conditioned hair, can extract live insects and nits. Comb through each section of hair for at least 10 minutes, repeating daily for a week.
Safety considerations differ by age. Children under two years should not receive permethrin or pyrethrin products; dimethicone or manual removal are preferred. Adults may use the same topical agents as older children, but should avoid excessive exposure to hair dyes or harsh chemicals that could increase scalp irritation.
Resistance monitoring is essential. Declining efficacy of pyrethrins in many regions necessitates confirming treatment success by re‑inspection 7 days post‑application. Persistent live lice indicate resistance and warrant switching to a different class, such as dimethicone or oral ivermectin.
Environmental control reduces reinfestation risk. Wash bedding, towels, and clothing used within 48 hours of treatment in hot water (≥ 60 °C) and dry on high heat. Items unable to be laundered may be sealed in plastic bags for two weeks. Vacuum carpets and upholstered furniture to remove stray lice.
Follow‑up assessment after the second treatment confirms eradication. Absence of live lice and nits within 1 cm of the scalp indicates successful resolution. Persistent findings require repeat of the chosen regimen or escalation to an alternative therapy.