Head Louse (Nit/Egg stage)

Scientific Name: Pediculus humanus capitis

Order & Family: Phthiraptera: Pediculidae

Size: Nits (eggs) are approximately 0.8 mm; adults reach 2.5 to 3 mm in length.

Head Louse (Nit/Egg stage)

Natural Habitat

Exclusively on the human scalp, typically found attached to hair shafts close to the scalp surface.

Diet & Feeding

Obligate hematophages; they feed exclusively on human blood several times a day.

Behavior Patterns

Nits are glued to hair shafts with a specialized cement. They cannot fly or jump and are transmitted through direct head-to-head contact or shared personal items. They hatch in about 8-9 days.

Risks & Benefits

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

Identified on: 2/17/2026