Introduction
A skin scraping is a diagnostic test used in almost every skin condition. An important use of this test is to detect mites, which are microscopic in size. Mites are far too small to be seen with the naked eye, and can only be positively diagnosed by a skin scraping and subsequent analysis of the scraped material under the microscope. The two mites we commonly diagnose by a skin scraping are Sarcoptic mange (Scabies) and Demodex.
Mites burrow into the skin or hair follicles, some burrowing deeper than others. Sometimes we need to perform several scrapings at various locations in order to find mites. Some mites have a propensity to affect certain areas, so these are the areas we emphasize when we perform the test. A negative skin scraping does not guarantee your pet is free of mites. Demodex mites are relatively easy to find under the microscope, while Scabies (Sarcoptes) mites can be very difficult to find under the microscope.
Obtaining a Sample
We use a scalpel bland to gently scrape the skin where the mites might be burrowed. You might see some redness of the area after this. This is due to the fact that the mites burrow into the skin so we need to get deep enough to find them. The redness goes away soon after.
We tend to do the skin scraping where a patch of hair is missing
We put the scraped material on a microscope slide
Analysis
The scraped material is put under a high powered microscope under bright light.
This is Allie, a veterinary student from Michigan State University learning how to use a microscope to look at a skin scraping. She is part of our student externship program where we train the students while they are still in veterinary school.
These students are required to post what they learned for the day on our Facebook page. It is called the Extern Daily Diary, and it goes back several decades.
Here is the Daily Diary Facebook post of a student learning how to work with ferrets
The slide is methodically analyzed for mites, mite eggs, or evidence of a fungal infection. This takes 5 minutes, so the report is available while you wait.