How many days do nits turn into lice? - briefly
Nits develop into mobile lice in roughly 7‑10 days, with the exact period influenced by temperature and species. Optimal conditions can shorten the cycle to about one week.
How many days do nits turn into lice? - in detail
The transformation from an egg (commonly called a nit) to a mobile louse follows a predictable schedule that depends mainly on temperature and humidity.
The egg is laid attached to a hair shaft and remains intact for 7–10 days at an ambient temperature of about 30 °C (86 °F). Cooler conditions lengthen this period; at 20 °C (68 °F) hatching may require up to 14 days.
Once the egg hatches, the emerging nymph passes through three successive instars. Each instar lasts approximately 1–2 days, during which the insect feeds on scalp blood and molts to the next stage. The cumulative duration of the three instars is therefore 3–6 days.
After the final molt, the insect becomes an adult louse capable of reproduction. The total time from egg attachment to a reproducing adult typically ranges from 9 to 12 days under optimal conditions, extending to 14–21 days when environmental factors are less favorable.
Key points
- Egg incubation: 7–10 days (30 °C); up to 14 days (20 °C).
- First instar: 1–2 days.
- Second instar: 1–2 days.
- Third instar: 1–2 days.
- Adult emergence: 9–12 days total under ideal conditions; slower in cooler, drier environments.
Understanding these intervals aids in timing treatment applications and assessing infestation severity.