Pubic louse
Scientific Name: Pthirus pubis
Order & Family: Order: Psocodea; Family: Pthiridae
Size: 1.1 mm to 1.8 mm (roughly the size of a pinhead)

Natural Habitat
Found exclusively on humans, primarily in the pubic hair region, but can also inhabit other coarse hair such as eyelashes, eyebrows, beard, and armpits.
Diet & Feeding
Obligate hematophage; they feed exclusively on human blood throughout all life stages.
Behavior Patterns
They are relatively immobile and remain attached to hair shafts; they move slowly by grasping thick hairs with their specialized large claws. The life cycle involves three stages: egg (nit), nymph, and adult. They are typically transmitted through close physical or sexual contact.
Risks & Benefits
Risks include intense itching (pruritus) caused by an allergic reaction to their saliva, and small bluish spots on the skin where they have fed. They do not typically transmit diseases but can lead to secondary skin infections from scratching. There are no ecological benefits to humans.
Identified on: 3/25/2026