Head Louse (specifically Nits/Eggs)

Scientific Name: Pediculus humanus capitis

Order & Family: Order: Psocodea; Family: Pediculidae

Size: Nits are approximately 0.8 mm long; adults are 2-3 mm (about the size of a sesame seed).

Head Louse (specifically Nits/Eggs)

Natural Habitat

Human scalp and hair, specifically attached to hair shafts near the base of the skull or behind the ears.

Diet & Feeding

Adults feed exclusively on human blood several times a day; nits (eggs) contain developing embryos and do not feed.

Behavior Patterns

Nits are firmly glued to host hair shafts and cannot be easily brushed away. They hatch in about 8-9 days. Adults are crawlers; they cannot jump or fly.

Risks & Benefits

Risks include intense itching (pruritus) due to an allergic reaction to louse saliva, secondary bacterial skin infections from scratching, and social distress. They are not known to transmit systemic diseases.

Identified on: 4/28/2026