Testing a possible new way to diagnose scabies

Summary This study, from a group based in different centres in France, has investigated a new non‐invasive (doesn't harm the skin in any way) method of diagnosing scabies. Scabies is an infestation due to a mite, sometimes called the itch mite, which burrows into the human skin causing a highly itchy rash. It is seen in children and the elderly, but it can affect people of any age and can be spread from person to person. It is difficult to diagnose as the main methods are either to take scrapings from the skin surface, or to examine the skin closely using a dermatoscope (surface microscope); both techniques require skill and interpretation. The new test discussed in this study is based on the rapid diagnostic technique known as the polymerase chain reaction, or PCR, which is used to identify specific pieces of the genetic code or DNA of the infecting organism, in this case a parasite, in skin material. The technique is simple to apply and uses a moistened swab which is lightly brushed over the affected areas, and this is then subjected to the PCR assay. In the study, about 38% of those patients with scabies infection, which had been proven using dermoscopy, had positive responses (i.e. shown to have scabies) in the new test. None of those without scabies infections were positive on PCR testing. This is the first step in the development of a potentially useful diagnostic technique. While the accuracy needs to be improved, it may become a useful tool for starting an investigation of a potential outbreak of scabies and, in the future, in diagnosing individual patients, rapidly and accurately. This summary relates to the study: Scabies polymerase chain reaction with standardized dry swab sampling: an easy tool for cluster diagnosis of human scabies