Where do head lice appear? - briefly
Head lice inhabit the hair and scalp of humans, concentrating on the nape of the neck, behind the ears, and the crown area where warmth and humidity are greatest; they may also be found on eyebrows and eyelashes. They survive only on a living host and do not infest clothing, bedding, or pets.
Where do head lice appear? - in detail
Head lice are obligate ectoparasites that live exclusively on the human scalp. The adult insects and their nymphs cling to hair shafts, where they feed on blood from the skin. The most common sites on the head include the crown, behind the ears, and the nape of the neck. Lice can also be found on eyebrows and eyelashes, though these locations are less frequent.
Transmission occurs through direct head‑to‑head contact. Items that bring hair into close proximity can also serve as vectors. Typical objects include:
- Hats, scarves, and helmets
- Hairbrushes, combs, and hair clips
- Pillows, pillowcases, and mattress covers
- Towels, washcloths, and clothing that contacts the head
These items can harbor lice for up to 48 hours, after which the insects usually die without a blood meal. Environments where close contact is common—such as schools, daycare centers, and family households—show higher prevalence because children frequently share personal items and engage in head‑to‑head play.
Outside the scalp, head lice are not adapted to survive on animals, furniture, or surfaces that lack hair. Their survival depends on a suitable temperature (approximately 30 °C) and regular access to blood. Consequently, the infestation remains confined to areas where hair is present and direct contact is possible.