Laboratory Diagnosis of Scabies Using a Simple Saline Mount: A Clinical Microbiologist's Report

Abstract

Scabies is a skin condition caused by infestation of the mite Sarcoptes scabiei. Sarcoptes scabiei var. hominis is an arthropod member belonging to the order Acarina. Scabies is present throughout the world and is prevalent in all age groups, mostly involving people frequently in contact with animals, children, women, and elderly people. Predisposing factors for scabies include individuals with immunosuppressive conditions and people residing under low socioeconomic conditions. Skin lesions that occur during mite infestation closely resemble dermatological disorders caused by microbes, including fungi, parasites, and viruses. Laboratory diagnosis of scabies greatly relies on an accurate clinical suspicion and the demonstration of mites in the skin scrapings could be used for confirmation. It should be noted that a greater understanding between a clinician or a dermatologist and a clinical microbiologist is required to successfully diagnose scabies. This report details an easily performed, cost-effective method, the simple saline mount, that a clinical microbiology laboratory should follow to successfully identify mites in skin scrapings.

Keywords: mite; sarcoptes scabiei; scabies; simple saline mount; skin diseases; skin scrapings.

Figure 1. Mite-infested patient showing disseminated hyperpigmented and scaly skin lesions

Figure 2. KOH preparation of skin scrapings reveal the presence of larval stages of mites within the skin

Figure 3. An adult mite as viewed after a simple saline wet mount