After how long do lice die? - briefly
Without a human host, head lice survive only about 24–48 hours before dying. Exposure to extreme temperatures—above 50 °C or below 0 °C—can eliminate them even more rapidly.
After how long do lice die? - in detail
Lice survive only under specific conditions. When deprived of a host, an adult head louse can live for approximately 24 hours. Nymphs, which have not yet fed, may die within 12 hours without blood. Temperature extremes accelerate mortality: exposure to 130 °F (54 °C) for 5 minutes or to 0 °F (‑18 °C) for 30 minutes eliminates all stages. Chemical treatments act faster; a single application of a pediculicide containing 1 % permethrin typically kills 95 % of adults within 10 minutes, while the remaining insects die during subsequent molts. Mechanical removal, such as combing with a fine-toothed lice comb, can physically extract live specimens; any insects left on the scalp after thorough combing usually perish within a day due to lack of nourishment. Summary of survival limits:
- Adult without host: ~24 h
- Nymph without host: ~12 h
- Heat exposure (130 °F/54 °C): 5 min
- Cold exposure (0 °F/‑18 °C): 30 min
- Standard pediculicide: 10 min to kill most adults
- Post‑comb removal: up to 24 h for remaining insects
Understanding these time frames guides effective eradication strategies.