How long do lice live in a pillow? - briefly
Adult head lice can survive on a pillow for roughly one to two days. After about 48 hours without a human host, they usually die from dehydration.
How long do lice live in a pillow? - in detail
Lice (Pediculus humanus capitis) cannot feed without a human host. When they fall onto a pillow, they survive only as long as their stored energy permits. Typical survival periods are:
- First 24 hours: Adult females may remain active, searching for a scalp. Their metabolism slows but they can still move.
- 24‑48 hours: Without blood, most adults become lethargic; many die due to dehydration.
- 48‑72 hours: A small fraction of nymphs and eggs (nits) may persist in a dormant state, but viability sharply declines.
- Beyond 72 hours: Survival probability drops below 5 %; eggs left on fabric rarely hatch because the required temperature and humidity are absent.
Key factors influencing these timelines include:
- Temperature: Ambient room temperatures (20‑22 °C) accelerate desiccation; higher heat (30 °C) shortens survival, while cooler conditions (15 °C) can extend it marginally.
- Humidity: Relative humidity above 50 % slows water loss, allowing lice to live a few hours longer. Dry environments (below 30 % humidity) cause rapid death.
- Pillow material: Natural fibers (cotton, wool) retain more moisture than synthetic polyester, modestly increasing lifespan. Foam or down pillows provide little shelter, leading to faster mortality.
- Presence of blood residues: Traces of scalp oils or blood can sustain insects for an extra day, but such deposits are uncommon on clean bedding.
Overall, adult head lice survive on a pillow for no more than three days, with most dying within one to two days. Nits left on the fabric are unlikely to develop unless transferred to a human scalp within that window. Regular laundering of pillowcases at 60 °C or higher eliminates any remaining insects and their eggs.