How long to treat lice? - briefly
Effective lice treatment typically spans 7–10 days, with a repeat application about a week after the first to eliminate newly hatched nits. Follow the product’s instructions and repeat the treatment as directed to ensure complete eradication.
How long to treat lice? - in detail
Effective lice eradication requires a clear schedule that addresses both the insects and their eggs. The standard regimen involves an initial application of a pediculicide followed by a repeat dose after a set interval. Most products recommend a second treatment 7–10 days after the first, aligning with the hatching period of nits that survive the initial exposure. This interval ensures that any newly emerged lice are eliminated before they can reproduce.
For over‑the‑counter shampoos containing permethrin (1 %) or pyrethrins, the protocol is:
- Apply to dry hair, saturate the scalp, leave for the prescribed time (usually 10 minutes).
- Rinse thoroughly, comb with a fine‑toothed lice comb to remove dead insects and loose nits.
- Wait 7 days, then repeat the entire process.
Prescription options such as ivermectin lotion or malathion (0.5 %) follow similar timing, though some clinicians advise a third application 14 days after the second if live nits persist.
Adjunct measures that support the timeline include:
- Washing bedding, clothing, and personal items in hot water (≥ 60 °C) or sealing them in plastic bags for two weeks.
- Avoiding head-to-head contact and sharing of combs, hats, or headphones during the treatment window.
- Conducting daily inspections with a lice comb for at least three weeks to confirm eradication.
If live lice are observed after the second dose, a third application may be necessary, but routine use of more than three treatments is discouraged due to resistance risk. In cases of persistent infestation despite correct adherence, a healthcare professional should be consulted for alternative therapies or combination regimens.