Louse egg (Nit) on a hair shaft

Scientific Name: Pediculus humanus capitis

Order & Family: Order: Psocodea (formerly Phthiraptera), Family: Pediculidae

Size: Nits are approximately 0.8 mm long; adult lice are 2 mm to 3 mm in length.

Louse egg (Nit) on a hair shaft

Natural Habitat

Found exclusively on the human scalp, attached to individual hair shafts near the base of the hair.

Diet & Feeding

Strictly bloodsucking; both nymphs and adults feed on human blood multiple times a day.

Behavior Patterns

Nits are glued to the hair shaft with a specialized cement. They hatch in 7-10 days into nymphs. Adults cannot fly or jump and spread primarily via direct head-to-head contact.

Risks & Benefits

Risks include intense itching (pruritus), sleep disturbance, and potential secondary bacterial skin infections from scratching. They are a significant nuisance but do not transmit major diseases like body lice.

Identified on: 1/15/2026