Human Head Louse
Scientific Name: Pediculus humanus capitis
Order & Family: Order Psocodea (Phthiraptera); Family Pediculidae
Size: Adults are approximately 2–3 mm in length (about the size of a sesame seed).
Natural Habitat
Exclusively on the human scalp, typically found on hairs near the nape of the neck and behind the ears.
Diet & Feeding
Obligate parasites that feed exclusively on human blood several times a day.
Behavior Patterns
They are wingless and cannot jump or fly; they move by crawling from hair to hair. Females lay eggs (nits) and cement them to the hair shaft near the scalp. They cannot survive more than 24 to 48 hours away from a human host.
Risks & Benefits
They do not transmit diseases. They cause itching due to an allergic reaction to their saliva during feeding, which can lead to secondary skin infections from scratching. They are considered a nuisance rather than a medical threat.
Identified on: 3/17/2026