After how many days does a lice infestation become apparent? - briefly
Visible signs usually emerge within one to two weeks after the eggs hatch, as nymphs begin feeding. Most infestations become noticeable between 7 and 10 days.
After how many days does a lice infestation become apparent? - in detail
A head‑lice infestation typically becomes noticeable within 7–10 days after the first egg is laid. The adult female deposits 4–6 eggs (nits) each day near the scalp. Eggs hatch after about 7 days, releasing nymphs that mature in another 7–10 days. During this period the scalp may not show obvious signs.
Visible indicators usually appear when nymphs begin feeding:
- Persistent itching caused by an allergic reaction to saliva.
- Small, white or yellowish specks attached to hair shafts (nits) that are difficult to remove.
- Live lice moving quickly on the scalp or hair strands.
If only nits are present without live insects, the infestation may still be in its early stage and symptoms can be minimal. Full symptom expression commonly occurs by the end of the second week after the initial egg‑laying event.
Factors that can accelerate detection:
- High infestation density, leading to more frequent bites.
- Sensitive individuals who react quickly to saliva, producing itching within a few days of nymph emergence.
- Regular scalp examinations that reveal nits before nymphs mature.
In summary, the period from egg deposition to observable signs ranges from one week (egg hatching) to two weeks (nymph maturation and feeding), with the most reliable markers—itching and moving lice—appearing around day 10‑14. Early inspection of hair shafts for nits can identify an infestation before these symptoms develop.