How many days are lice treated? - briefly
Lice are usually eradicated with a treatment course lasting 7 – 10 days, followed by a second application about a week later to eliminate any newly hatched insects.
How many days are lice treated? - in detail
Effective lice eradication requires a treatment plan that spans the entire life cycle of the parasite. Adult head‑lice survive for about 30 days, but eggs hatch in 7–10 days. Because a single application cannot kill all nits, most regimens include two applications separated by a week‑plus interval.
Typical schedule
- Day 1: Apply a pediculicide (permethrin 1 %, pyrethrin with piperonyl‑butoxide, or a prescription‑only agent such as ivermectin or malathion). Follow the product’s instructions for contact time, then rinse thoroughly. Comb out visible nits with a fine‑toothed lice comb.
- Day 7–10: Re‑apply the same product or a second‑line medication. This targets newly emerged nymphs that survived the first treatment.
- Day 14–21: Perform a final combing session to remove any residual nits. Some clinicians advise a third application if live lice are still detected.
Factors influencing duration
- Product type: Over‑the‑counter shampoos often require a repeat dose at 7 days; prescription lotions may be effective with a single dose but still recommend a follow‑up treatment.
- Resistance: In regions with documented resistance to pyrethroids, longer intervals (10 days) or alternative agents are advised.
- Infestation severity: Heavy loads of nits may necessitate additional combing sessions and possibly a third chemical application.
- Compliance: Accurate timing of repeat doses is critical; missing the 7–10 day window reduces efficacy.
Summary
A complete therapeutic course usually lasts 14 days, encompassing an initial treatment, a second dose 7–10 days later, and a final inspection or combing phase up to three weeks after the first application. Adjustments are made based on product choice, resistance patterns, and the number of nits present.