Which comes first: nits or lice? - briefly
Nits, the eggs, are deposited first; they hatch into lice after several days. The presence of nits therefore precedes the appearance of adult insects.
Which comes first: nits or lice? - in detail
Nits are the eggs deposited by adult head‑lice on hair shafts close to the scalp. Each female lays 6–10 eggs per day, securing them with a cement that hardens within minutes. The eggs remain attached for about 7–10 days before the embryos hatch into nymphs, which then mature into reproductive adults after an additional 7–10 days.
Because the egg stage must exist before any hatching can occur, the presence of nits necessarily precedes the emergence of live lice. Detectable nits can be seen on hair strands even when no live insects are present, whereas an infestation of crawling or adult lice cannot be confirmed until after hatching has taken place.
Key points of the life‑cycle timeline:
- Egg deposition: day 0‑10 of infestation.
- Egg incubation: 7–10 days; eggs are visible as translucent or brownish ovals glued to hair.
- Nymph emergence: immediately after incubation; nymphs resemble adults but are smaller and unable to reproduce.
- Maturation to reproductive adult: another 7–10 days.
Consequences for diagnosis and treatment:
- Early detection focuses on locating nits, especially those that are firmly attached and close to the scalp.
- Treatment applied before hatching can eliminate the entire population, as the eggs will not survive once the cement is disrupted.
- Re‑infestation is unlikely if all nits are removed; otherwise, surviving eggs will hatch and repopulate the host.
In summary, the egg stage appears first, and only after the eggs have been laid and incubated can live lice be observed.