
Community identification
Pubic louse (Crabs)
Pthirus pubis
- Order & Family
- Order: Psocodea; Family: Pthiridae
- Size
- 1.1 mm to 1.8 mm (about the size of a pinhead)
Natural Habitat
Found exclusively on humans, specifically in coarse hair such as pubic, armpit, chest, or facial hair (eyelashes/eyebrows).
Diet & Feeding
Strictly hematophagous; they feed exclusively on human blood multiple times a day.
Behavior Patterns
They are obligate ectoparasites that cannot jump or fly; they move by crawling from hair to hair. Females lay eggs (nits) on hair shafts. They cannot survive more than 24-48 hours off a human host.
Risks & Benefits
Risk: Causes intense itching (pruritus) and blue spots (maculae ceruleae) at feeding sites. They can cause secondary skin infections from scratching. They are typically transmitted via close physical contact. Benefit: None.