How do lice appear on a person's hair? - briefly
Lice infest a person’s hair when adult females deposit eggs on strands near the scalp after being transferred through direct head‑to‑head contact or shared items such as combs, hats, or bedding. The eggs hatch in several days, and the emerging nymphs feed on blood, rapidly establishing a colony.
How do lice appear on a person's hair? - in detail
Head lice (Pediculus humanus capitis) colonize a scalp when an adult female deposits her eggs (nits) on hair shafts close to the scalp. The female can transfer directly from an infested person through head-to-head contact, which is the most efficient route because lice cannot jump or fly. Indirect transfer occurs when live lice or viable nits cling to personal items such as combs, hats, scarves, pillows, or upholstered furniture; they survive for up to 48 hours away from a host, allowing occasional spread through shared objects.
Once a viable nit hatches, the emerging nymph begins feeding on blood within 24 hours and matures through three molts over about 7–10 days. Mature females lay 5–10 eggs per day for up to three weeks, maintaining the population. High infestation risk correlates with crowded environments, frequent close contact, and inadequate hygiene practices, although lice do not thrive on cleanliness alone.
Key factors that facilitate colonization:
- Direct head contact lasting several minutes.
- Presence of viable nits attached within 1 mm of the scalp.
- Warm, humid scalp conditions that support feeding.
- Lack of regular inspection and removal of nits.
Preventive measures focus on minimizing head-to-head interactions, avoiding the sharing of personal headgear, and conducting routine scalp examinations, especially in settings where close contact is common. Early detection and removal of nits interrupt the life cycle and prevent population buildup.