What appears first: nits or lice? - briefly
Nits, the eggs deposited by adult lice, appear before any lice are visible; they hatch into nymphs that develop into mature insects.
What appears first: nits or lice? - in detail
The reproductive cycle of the human head louse begins with the female depositing eggs on the hair shaft. These eggs, commonly called nits, are cemented to the strand within a few minutes of being laid. The incubation period lasts about seven to ten days, after which each egg hatches into a mobile nymph. The nymph undergoes three molts over roughly fourteen days before reaching adulthood. Consequently, the first observable element in an infestation is the egg, not the crawling insect. Detection methods therefore focus on identifying the tiny, oval, whitish structures attached close to the scalp before live lice become apparent.
Key points of the life‑stage sequence:
- Egg deposition (nits) – immediate after mating, visible within hours.
- Incubation – 7–10 days, no movement.
- Nymph emergence – small, translucent, begin feeding.
- Maturation – three molts, total ~21 days to adult.
Because the egg precedes the appearance of any moving parasite, any new outbreak will initially present only with nits. Only after the incubation period will live lice be present in detectable numbers.