How quickly does lice infection manifest? - briefly
Symptoms typically appear within 4–10 days after the first egg hatches, when nymphs begin feeding. The earliest sign is usually itching caused by their bites.
How quickly does lice infection manifest? - in detail
Lice infestations become apparent within a short time after the first eggs hatch. Female head lice lay 5‑10 eggs (nits) each day, attaching them to hair shafts near the scalp. Eggs incubate for 6‑9 days; once they hatch, the nymphs begin feeding immediately. Visible signs typically emerge 7‑10 days after the initial contact with an infested individual.
Key milestones in the development timeline:
- Egg (nit) stage: 6‑9 days; no symptoms, but nits may be seen as tiny, whitish ovals glued to hair.
- Nymph stage: 9‑12 days; immature lice feed several times daily, causing itching and irritation.
- Adult stage: 14‑21 days; fully mature lice reproduce, increasing the population and intensifying symptoms.
Symptoms that signal the presence of lice include:
- Persistent itching caused by saliva injected during feeding.
- Small red bumps on the scalp or neck.
- Presence of live lice or nits within 1 cm of the scalp.
- Occasionally, secondary bacterial infection from scratching.
The speed of manifestation depends on factors such as the number of eggs transferred, the host’s hair length, and personal hygiene practices. In densely populated settings (schools, camps), transmission can lead to noticeable infestations within a week, whereas isolated cases may remain undetected for longer if only a few nits are present. Prompt inspection and treatment interrupt the life cycle before the population expands, reducing the period of visible symptoms.