How can the burrows of a scabies mite be seen? - briefly
The burrows appear as thin, serpentine, translucent tracks on the skin surface and can be visualized most clearly with a dermatoscope or by applying a thin layer of mineral oil to enhance contrast.
How can the burrows of a scabies mite be seen? - in detail
Scabies burrows appear as thin, gray‑white or skin‑colored lines on the epidermis. They are most often located on the wrists, interdigital spaces, elbows, axillae, waistline, and genital region. Direct observation requires proper lighting and magnification.
Techniques for detection
- Dermatoscopy: Handheld dermatoscopes provide 10–30× magnification and polarized light, revealing the characteristic S‑shaped or serpentine tracks that contain a mite, eggs, and fecal pellets. The “jet‑liner” sign—an opaque line with a darker center—indicates the mite’s location.
- Wood’s lamp: Ultraviolet illumination (365 nm) accentuates the burrow’s contour by highlighting the surrounding erythema, though the mite itself does not fluoresce.
- Microscopic skin scrapings: Collecting superficial scales with a scalpel blade, then examining the material at 100–400× magnification, allows direct visualization of the mite, its eggs, and the surrounding tunnel.
- High‑resolution photography: Macro lenses combined with cross‑polarized lighting capture clear images of the tracks, useful for documentation and teledermatology.
Preparation steps
- Clean the area with alcohol to remove crusts and reduce glare.
- Apply a drop of immersion oil if using a dermatoscope to improve optical clarity.
- Position the device perpendicular to the skin to avoid distortion of the line.
- Scan the suspected region systematically, moving from proximal to distal sites.
- Record any observed burrow, noting length, orientation, and presence of a visible mite at the end.
Interpretation cues
- A linear or curved groove measuring 2–10 mm, often ending in a small vesicle or papule, suggests active infestation.
- The “delta sign” (a triangular dark area at the burrow’s terminus) indicates the mite’s head.
- Multiple parallel tracks in close proximity point to heavy mite load.
Combining dermatoscopic examination with microscopic scraping yields the highest diagnostic accuracy, enabling clinicians to confirm scabies and initiate appropriate treatment.