When do lice eggs hatch? - briefly
Lice eggs typically hatch within 7–10 days after being laid when ambient temperature is around 30 °C. Cooler environments can prolong incubation to roughly 14 days.
When do lice eggs hatch? - in detail
Lice eggs, commonly called nits, develop within a protective shell that adheres to hair shafts close to the scalp. The incubation period depends primarily on temperature, which is regulated by the host’s body heat. Under normal human scalp conditions (approximately 32–34 °C or 90–93 °F), the eggs typically hatch after 7 to 10 days.
If the ambient temperature drops below the optimal range, development slows, extending the hatch time to up to 12 days. Conversely, higher temperatures can accelerate embryogenesis, causing emergence as early as 5 days, though this is less common in natural infestations.
The hatching process follows a defined sequence:
- Embryo matures inside the operculum, the transparent cap covering the egg.
- Enzymatic activity weakens the operculum’s attachment to the shell.
- The nymph pushes through the opening, emerging as a newly hatched louse.
After emergence, the nymph requires an additional 9 to 12 days to reach adulthood, during which it molts three times. Understanding the precise timing of egg hatching assists in scheduling effective treatment cycles, ensuring that any surviving eggs are targeted before they release new lice.