How many days does a lice infection last in a child? - briefly
Effective treatment usually clears a child's head‑lice infestation within 7–10 days; without treatment, adult lice may survive up to a month, while immature lice live about 5–7 days.
How many days does a lice infection last in a child? - in detail
A head‑lice infestation in a child generally persists for about 7 to 10 days after an effective treatment regimen is completed. This timeframe reflects the biological life cycle of Pediculus humanus capitis: eggs (nits) hatch in 7–10 days, nymphs mature to adults within another 5–7 days, and adult lice survive roughly 30 days without a blood meal. Properly applied pediculicidal products eliminate live lice within 24 hours, but viable eggs can hatch later, requiring a second application 7–10 days after the first to eradicate newly emerged nymphs.
Key factors influencing the overall length of the problem:
- Treatment efficacy – correct dosage, thorough application to dry hair, and adherence to the recommended repeat dose.
- Egg survival – missed nits may hatch after the initial kill, extending the infestation by another week.
- Re‑exposure – contact with untreated contacts (classmates, caregivers) can re‑introduce lice, resetting the timeline.
- Hair length and type – longer or thicker hair can hinder complete coverage, increasing the risk of residual eggs.
- Compliance with environmental measures – washing bedding, hats, and personal items reduces the chance of reinfestation.
Typical management protocol:
- First treatment – apply a licensed insecticide (e.g., permethrin 1 % or dimethicone) according to label instructions; leave on hair for the specified duration.
- Nit removal – comb wet hair with a fine‑toothed nit comb, section by section, to extract as many eggs as possible.
- Second treatment – repeat the application 7–10 days later to target hatchlings that escaped the first round.
- Follow‑up inspection – examine the scalp 2–3 days after the second dose; absence of live lice indicates resolution.
- Preventive steps – launder clothing, bedding, and personal items in hot water (≥ 60 °C) or seal them in a plastic bag for two weeks; avoid sharing combs, hats, or hair accessories.
When all steps are executed correctly, the infestation should be cleared within two weeks. Persistent symptoms beyond 14 days suggest treatment failure, resistance, or ongoing exposure and warrant a reassessment by a healthcare professional.