What can be applied to the head for lice? - briefly
Topical agents such as permethrin 1 % shampoo or pyrethrin‑based lotions eradicate head lice, while silicone‑based products like dimethicone physically coat and suffocate the insects. Oral ivermectin, prescribed by a physician, provides an alternative systemic option.
What can be applied to the head for lice? - in detail
Effective scalp treatments for pediculosis include both chemical and non‑chemical agents.
Chemical options are formulated as lotions, shampoos, or sprays and contain insecticidal compounds that act on the nervous system of the parasite. Commonly used substances are:
- Permethrin 1 % (synthetic pyrethroid) – applied to dry hair, left for 10 minutes, then rinsed; a second application after 7–10 days eliminates newly hatched nymphs.
- Pyrethrins combined with piperonyl‑butoxide – similar protocol to permethrin; resistance reported in some regions.
- Malathion 0.5 % – applied to damp hair, left for 8–12 hours, then washed off; suitable for resistant infestations.
- Benzyl alcohol 5 % lotion – non‑neurotoxic, kills lice but not eggs; requires a repeat treatment after 7 days.
- Ivermectin 0.5 % lotion – applied to dry hair, left for 10 minutes; effective against resistant strains, single application often sufficient.
- Spinosad 0.9 % suspension – applied to dry hair, left for 10 minutes; kills lice and some eggs; repeat after 7 days recommended.
Non‑chemical alternatives rely on physical mechanisms rather than toxicity. Primary choices are:
- Dimethicone‑based products (silicone oil) – coat lice, causing immobilization and death; applied to dry hair, left for 10 minutes, then rinsed; repeat after 7 days.
- Wet combing with a fine‑toothed nit comb – hair soaked in water and conditioner, combed repeatedly to remove live insects and eggs; requires daily sessions for at least 10 days.
- Essential‑oil preparations (e.g., tea‑tree, lavender) – limited evidence of efficacy; may cause skin irritation; not recommended as sole therapy.
Prescription‑only formulations, such as malathion and ivermectin, require medical authorization. Over‑the‑counter products contain the listed active ingredients in concentrations approved for consumer use.
Application guidelines common to most topical treatments:
- Apply to clean, dry hair unless product instructions specify dampness.
- Distribute evenly from scalp to tips, ensuring complete coverage of hair shafts.
- Observe required exposure time; premature rinsing reduces efficacy.
- Rinse thoroughly with warm water; avoid hot water that may degrade the active ingredient.
- Perform a second treatment according to the product’s schedule, typically 7–10 days after the first, to target hatching nits.
Adjunct measures reduce reinfestation risk:
- Wash bedding, clothing, and personal items in hot water (≥ 60 °C) or seal in plastic bags for two weeks.
- Vacuum carpets and upholstered furniture.
- Avoid head‑to‑head contact and sharing of combs, hats, or hair accessories.
Efficacy assessments rely on visual inspection of the scalp 1–2 weeks post‑treatment. Absence of live lice and a decline in viable nits indicate successful eradication. Persistent infestation after two treatment cycles warrants specialist evaluation for alternative regimens.