Pubic Louse (Crab Louse)
Scientific Name: Pthirus pubis
Order & Family: Order: Psocodea (formerly Anoplura), Family: Pthiridae
Size: 1.1 mm to 1.8 mm (roughly the size of a pinhead)
Natural Habitat
The coarse hairs of the human body, most commonly in the pubic area; also occasionally found in eyelashes, eyebrows, chest hair, or armpits.
Diet & Feeding
Obligate ectoparasites that feed exclusively on human blood several times a day.
Behavior Patterns
They are slow-moving and cling to hair shafts with specialized claw-like legs. They cannot jump or fly and are usually transmitted through close physical contact or shared personal items.
Risks & Benefits
Risk: Causes intense itching (pruritus) due to an allergic reaction to their saliva. While they do not transmit major diseases, secondary skin infections can occur from scratching. Benefit: None to humans; they are strictly parasitic.
Identified on: 2/17/2026