How long can lice live in bed linen? - briefly
Lice survive only a short time without a human host, typically dying within 24 hours and certainly not beyond 48 hours on fabric. Consequently, infested bedding becomes non‑viable for the insects after one to two days.
How long can lice live in bed linen? - in detail
Lice survive on fabric only as long as they can obtain moisture and a suitable temperature. Adult head‑lice (Pediculus humanus capitis) can live up to 48 hours without a host, while nymphs survive slightly less, typically 24–36 hours. Egg (nit) viability on linens is limited; once detached from the scalp, the egg loses the necessary warmth and humidity and generally hatches within 24 hours if conditions remain favorable, but most fail to develop.
Key factors influencing survival on sheets and pillowcases:
- Temperature: Optimal range is 30–32 °C (86–90 °F). Cooler environments (below 20 °C) reduce lifespan dramatically, often to under 12 hours.
- Humidity: Relative humidity above 50 % supports longer survival; dry air accelerates desiccation.
- Fabric type: Natural fibers (cotton, linen) retain moisture longer than synthetics, marginally extending lice viability.
- Exposure to sunlight: Ultraviolet light rapidly kills both adults and nits.
Practical implications for control:
- Wash bedding in hot water (≥ 60 °C) and dry on high heat for at least 30 minutes; this eliminates any remaining insects and eggs.
- If washing is not possible, seal linens in a plastic bag for 48 hours; the lack of food and gradual desiccation will kill the lice.
- Regularly change and launder pillowcases and sheets to prevent re‑infestation.
In summary, lice can persist on bed linen for a maximum of two days under ideal conditions, but typical household environments shorten this period to less than one day. Effective laundering or isolation removes the risk.