How long does it take for lice larvae to hatch? - briefly
Lice eggs need roughly 7 – 10 days to develop and hatch into nymphs under typical indoor conditions. Higher ambient temperatures (around 30 °C) can shorten this interval, whereas cooler environments prolong it.
How long does it take for lice larvae to hatch? - in detail
The incubation period of lice eggs, commonly called nits, lasts approximately seven to ten days under normal indoor temperatures (20‑25 °C). During this interval the embryo develops within the sealed shell and, when ready, the emerging nymph breaks through the operculum and drops onto the scalp.
Key factors influencing the duration include ambient temperature, humidity, and the species involved. Higher temperatures (above 30 °C) can shorten the period to five‑six days, whereas cooler conditions (below 15 °C) may extend it to twelve days or more. Relative humidity between 50 % and 70 % supports optimal development; extreme dryness slows hatching, while excessive moisture can cause egg desiccation.
After emergence, the nymph resembles an adult but is smaller and lacks fully developed reproductive organs. It undergoes three successive molts, each lasting roughly two to three days, to reach maturity. Consequently, the complete transformation from egg to reproducing adult spans about ten to fourteen days, depending on environmental conditions.
For detection, nits remain firmly attached to the hair shaft with a cement-like substance. The presence of translucent, oval-shaped shells close to the scalp indicates recent oviposition, whereas darker, hardened shells farther from the scalp suggest older, possibly non‑viable eggs. Effective treatment must target both the eggs and the subsequent nymphal stages to interrupt the life cycle.