Pubic Louse

Scientific Name: Pthirus pubis

Order & Family: Order: Psocodea (suborder Anoplura); Family: Pthiridae

Size: 1.1 mm to 1.8 mm in length; they are shorter than head lice and crab-like in appearance.

Pubic Louse

Natural Habitat

Coarse human body hair, primarily in the pubic region, but occasionally found in eyelashes, eyebrows, beards, or armpits.

Diet & Feeding

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

Behavior Patterns

They are slow-moving and spend their entire life cycle on the host. Females lay eggs (nits) and glue them to hair shafts. They cannot survive for more than 24-48 hours away from a human host.

Risks & Benefits

Risk: Causes intense itching (pruritus) due to an allergic reaction to their saliva; can lead to secondary skin infections from scratching. They do not transmit major diseases but are considered a sexually transmitted infection (STI). Benefit: None to humans or ecosystems.

Identified on: 1/14/2026