How can the pubic louse be seen? - briefly
The pubic louse is a 1–2 mm crab‑shaped insect that can be observed without magnification on the base of pubic hair. It appears as a grayish‑brown oval body with six legs, the front pair specialized for grasping hair shafts.
How can the pubic louse be seen? - in detail
The pubic louse (Pthirus pubis) is a tiny ectoparasite, typically 1–2 mm in length, with a crab‑like body and three pairs of clawed legs adapted for grasping coarse hair. Its coloration ranges from gray‑white to brown, depending on the amount of ingested blood.
Direct visual inspection
- Examine the pubic region, axillae, chest hair, and beard with the naked eye in bright, natural light. Look for live insects moving slowly across hair shafts.
- Identify the characteristic oval, translucent nits attached firmly to the base of hairs, usually within 1 mm of the scalp.
Magnified observation
- Use a handheld magnifying glass (×10) or a dermatoscope (×10–×20) to enhance detail. The louse’s body appears flattened, with a broad abdomen and a distinct head bearing short antennae.
- Under magnification, the three pairs of legs are visible, each ending in a sharp claw that clings to hair.
Microscopic examination
- Collect a sample of hair with attached insects or nits and place it on a slide with a drop of saline solution. Cover with a coverslip and observe under a light microscope at 40–100× magnification. The louse’s exoskeleton shows a smooth cuticle, and the eggs display a characteristic operculum at one end.
Alternative lighting techniques
- Employ a Wood’s lamp (UV light) to highlight the louse’s body, which may fluoresce faintly, aiding detection in dense hair.
- Use a portable LED lamp to illuminate the area, reducing shadows and improving contrast for visual spotting.
By combining naked‑eye inspection with magnification tools and, when necessary, microscopic analysis, the pubic louse can be reliably identified and distinguished from other hair‑associated organisms.