COMPARATIVE STUDY OF DERMOSCOPY, SKIN SCRAPING, AND THE ADHESIVE TAPE TEST FOR THE DIAGNOSIS OF SCABIES IN A TERTIARY HEALTH CARE CENTER, UTTAR PRADESH

Abstract

Background &Aims: Scabies is a parasitic skin disease endemic in resource-poor communities. The best ways to diagnose scabies in this setting have not been investigated. To compare study of dermoscopy, skin scraping, and the adhesive tape test for the diagnosis of scabies in 120 patients. Methods: A comparative study was done in 120 patients, the patient were divided in 3 equal groups, and each group were subjected to be examined by one of the modalities i.e. Dermatoscopy, skin scraping and adhesive tape test. The patient then were examined dermoscopically. After the dermoscopy, the adhesive tape test was performed and a skin scraping was obtained. Skin scrapings and adhesive tape test was transferred to a glass slide and examined. Dermoscopy, skin scraping, and the adhesive tape test was performed at 3 topographic areas where mites were suspected. If the patient had more than 3 suspicious lesions, the selection of sites was left to the discretion of the investigator. If the patient had 3 or fewer lesions, all lesions were examined. For technical reasons, although conducted at the same body area, the adhesive tape test and the skin scraping was performed on different but closely located lesions. Results: In total, 44 of 120 patients (36.3%) were diagnosed with scabies. Ÿ The dermoscopy sensitivity was signicantly higher then that of skin scraping and the adhesive tape test (both P .001) The specicity of dermoscopy was low (0.46; 95% CI, 0.34-0.58) and signicantly less than that of the adhesive tape test and skin scraping (both P .001). Ÿ Dermoscopy and the adhesive tape test had the same negative predictive value (0.85; 95% CI, 0.69-0.94 and 0.75-0.91, respectively). Ÿ The sensitivity of dermoscopy and the adhesive tape test according to clinical characteristics of the patients. The sensitivity of both tests decreased with increasing duration of the infestation. Ÿ The sensitivity of dermoscopy increased parallel to the severity of scabies (light scabies, 0.80; moderate scabies, 0.85; and severe scabies, 0.93); however, the differences were not signicant. Conclusion: When trained personnel are available, dermoscopy is a valid tool for diagnosing scabies in a resource-poor setting. The adhesive tape test is easy to perform and, because it has high positive and negative predictive values, the test is ideal for screening purposes. Skin scraping cannot be recommended as a diagnostic tool in this setting