Pubic Louse

Scientific Name: Pthirus pubis

Order & Family: Order: Psocodea; Family: Pthiridae

Size: 1.1 mm to 1.8 mm (about the size of a pinhead)

Pubic Louse

Natural Habitat

Found exclusively on humans, primarily in the pubic and perianal regions, but can occasionally be found in other coarse hair such as eyelashes, eyebrows, beard, or chest hair.

Diet & Feeding

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

Behavior Patterns

They are slow-moving and possess large claws used to grasp onto coarse hair. They do not jump or fly and generally remain attached to hair for their entire thirty-day life cycle, laying eggs (nits) near the base of the hair shaft.

Risks & Benefits

They cause intense itching (pruritus) and reddish/blue lesions on the skin due to an allergic reaction to their saliva. While they do not transmit serious diseases, infestation can lead to secondary skin infections from scratching. They have no environmental benefits.

Identified on: 1/13/2026