How long does it take for lice to hatch from nits? - briefly
Lice eggs normally incubate for 7–10 days before the nymph emerges. Environmental factors such as temperature and humidity may shift the period slightly, but the hatch time remains roughly a week to ten days.
How long does it take for lice to hatch from nits? - in detail
Lice eggs, commonly called nits, require a specific incubation period before the nymph emerges. Under typical indoor conditions—ambient temperature around 30 °C (86 °F) and relative humidity of 70 %—the development time averages 7 to 10 days. The process can be summarized as follows:
- Temperature effect: Higher temperatures accelerate embryonic growth; at 35 °C (95 °F) hatching may occur in 5–6 days, while cooler environments near 20 °C (68 °F) can extend the period to 12–14 days.
- Humidity influence: Adequate moisture supports egg viability; low humidity (<50 %) can delay or inhibit hatching, whereas optimal humidity maintains normal timing.
- Species variation: Pediculus humanus capitis (head louse) follows the 7–10‑day range, whereas Pediculus humanus corporis (body louse) shows a comparable schedule but may vary slightly with clothing‑related microclimates.
- Egg placement: Eggs firmly attached to hair shafts near the scalp receive more consistent warmth, leading to the standard incubation window; eggs laid farther from the scalp experience slower development.
After hatching, the newly emerged nymph resembles an adult louse but is smaller and requires an additional 5–7 days of molting through three instars before reaching reproductive maturity. Consequently, the complete cycle from egg deposition to a breeding adult spans approximately 12 to 17 days, depending on environmental conditions.