Scabies

Usually, your doctor can diagnose scabies if you have:

• Severe itching, especially at night.
• A rash, sometimes with skin sores . These may look like tiny curving tracks. Sometimes you may have a small blister or see a tiny black dot at one end of the track. In babies, the tracks may look more like red and inflamed skin, sometimes with small sores that are like blisters. Your doctor will check your skin for redness, sores, scratches, raw areas, or scabs that are typical of scabies infestation.
• Other family members or people you are physically close with who are also itching or who have recently been diagnosed with scabies.

Sometimes you may need one of the following tests to confirm the diagnosis:

• Skin scrapings. Your doctor collects material from the itchy area by applying a drop of mineral oil or other liquid to the skin and then scraping the area with a scalpel. He or she then examines the scrapings under a microscope to look for scabies mites, eggs, egg casings, or feces. This is the most common test used to diagnose scabies.
• Needle extraction of the mite. The doctor may use a needle to remove a mite from the burrow. The mite is placed on a slide and examined under a microscope.
• Ink test or ink burrow test. Your doctor strokes a washable felt-tip pen across the itchy areas. The surface ink is wiped off with water or an alcohol swab. Any burrows present will absorb the ink and be seen as a dark line.
• Skin biopsy/punch biopsy. A skin sample (punch biopsy or shave biopsy) may be helpful in diagnosing difficult-to-diagnose conditions. Skin biopsy is rarely used.