What are lice that live on the head called? - briefly
The insects that infest human scalps are called head lice (Pediculus humanus capitis). They are tiny, wingless parasites that feed on blood from the hair follicles.
What are lice that live on the head called? - in detail
Head lice are the small, wingless insects that infest human scalps. Their scientific designation is Pediculus humanus capitis, a subspecies of the human louse that specifically colonises hair and sebaceous secretions. Adult specimens measure 2–4 mm, possess six legs with clawed tarsi adapted for grasping hair shafts, and exhibit a gray‑white coloration that darkens after a blood meal.
The life cycle comprises three stages:
- Egg (nit): Oval, 0.8 mm long, firmly cemented to the hair shaft near the scalp. Incubation lasts 7–10 days.
- Nymph: Emerges from the egg, undergoes three molts over 9–12 days. Each instar resembles the adult but is smaller.
- Adult: Reaches reproductive maturity within 1 week, lives up to 30 days on the host. Females lay 6–10 eggs per day.
Transmission occurs through direct head‑to‑head contact; indirect spread via personal items (combs, hats, bedding) is less common but possible. Diagnosis relies on visual inspection for live insects and viable nits attached within 1 cm of the scalp. Viable nits are identified by a firm, translucent shell and a visible operculum; empty shells are pale and brittle.
Effective control measures include:
- Topical pediculicides: Permethrin 1 % lotion, pyrethrin‑based products, or dimethicone preparations applied according to manufacturer instructions.
- Mechanical removal: Fine‑toothed combs used on wet, conditioned hair to extract live lice and nits; repeat sessions every 2–3 days for two weeks.
- Environmental decontamination: Washing bedding, clothing, and personal items in hot water (≥ 60 °C) or sealing non‑washable items in airtight bags for 2 weeks.
Resistance to pyrethroid compounds has been documented in many regions; alternative agents such as ivermectin or spinosad may be required when standard treatments fail. Regular follow‑up examinations at 7‑day intervals confirm eradication and prevent reinfestation.