Skin scraping

Detection of Sarcoptes scabiei (scabies) by examining skin scrapings under a microscope.

• Plan to obtain at least 2-3 scrapings from separate locations on the body
• Use a separate slide and cover slip for each scraping
• Each slide must be labeled
• Examination of the patient’s skin
• Sample should be taken from unexcoriated burrows, or intact papules
• Place a small drop of mineral oil in the center of the labeled slides
• Place a drop of mineral oil on the lesions to be scraped and evenly spread the oil over the area to be sampled
• A surgical blade or hypodermic needle may be used to collect the scraping
• Pull the skin taut
• Apply slight pressure while making several scraping passes over the lesion
• If using a needle, best results are obtained when the needle is held at a 5-degree to 10-degree angle to the skin surface.
• A surgical blade may also be used to collect samples:
  • Hold the blade at 90-degrees to the skin surface and lightly scrape the area to be sampled
  • A small amount of bleeding may occur but will not interfere with the examination
• Transfer the needle/blade scrapings from the lesion to a prepared slide and place a cover slip on slide. The slide should have visible skin cells on it.
• A small amount of blood in the sample will not interfere with microscopy
• When specimen collection is complete, wipe each area where a scraping was conducted with an alcohol wipe

• Sharps container
• Disposable gloves
• Alcohol-based sanitizer
• Magnifying lens and light source
• Alcohol wipes
• 2-3 glass slides and 2-3 cover slips
• Clinical scalpel blade / Sterile surgical blades / hypodermic needle (gauge 23 or 25)
• Mineral oil and dropper

• It is critical to do a thorough examination of the patient’s skin.
• The use of a hand-held magnification lens and good lighting are often required for identifying lesions to be sampled.
• Although 80% of mites are found in the webbing between the fingers on the hands, and on the folds of wrists, they can also be found on the shoulders, back, abdomen, elbows, buttocks, axillae, under the breasts, behind the knees, and on the thighs.
• The mites burrow into the skin, but never below the outer layer of the epidermis, the stratum corneum.
• Look for burrows, which will appear as serpentine, redline marking tunnels in the skin up to several centimeters long and unexcoriated papules (unscratched bumps) that suggest site of active mites.
• The mites will not be easily demonstrated in excoriated, scabbed, or infected skin.