How do lice appear on the head? - briefly
Lice reach a scalp primarily through direct head‑to‑head contact or by sharing items such as combs, hats, or pillows that have viable eggs attached. Once on the hair, the eggs hatch and the nymphs feed on blood, establishing an infestation.
How do lice appear on the head? - in detail
Lice are obligate ectoparasites that colonize human hair shafts. Their presence on the scalp begins when viable individuals are transferred from one host to another.
Direct head‑to‑head contact provides the most efficient route for transfer. Situations that increase such contact include school classrooms, sports teams, and childcare settings. Indirect transfer occurs through shared objects that contact hair, such as combs, hats, scarves, pillows, and hair accessories. Eggs (nits) attached to these items can hatch after reaching a suitable host, completing the transmission cycle.
The life cycle consists of three stages. Adult females lay eggs near the scalp, securing them to the hair shaft with a cementing substance. Eggs hatch in 7–10 days, releasing nymphs that resemble miniature adults. Nymphs undergo three molts over approximately 9–12 days before reaching reproductive maturity. An adult female can produce 6–10 eggs per day, allowing rapid population growth under favorable conditions.
Factors that facilitate infestation include:
- Frequent close physical interaction among individuals,
- Use of personal items without regular cleaning,
- Overcrowded living conditions,
- Limited access to effective treatment options.
Visible indicators of infestation comprise live insects moving through hair, brownish or grayish nits attached within 1 mm of the scalp, and localized itching caused by saliva injection during feeding. Early detection relies on systematic examination of the hair base and scalp, preferably with a fine-tooth comb under adequate lighting.
Preventive measures focus on minimizing direct contact, avoiding the sharing of personal hair items, and maintaining regular cleaning of bedding and clothing. Prompt treatment of identified cases, combined with simultaneous treatment of close contacts, interrupts the reproductive cycle and reduces the likelihood of re‑infestation.