Diagnostic Accuracy of Dermoscopy for Scabies

Abstract

The diagnostic accuracy of dermoscopy (DS) for scabies, a highly contagious parasitic disease, remains disputed. This study aimed to assess the diagnostic accuracy of DS in scabies, analyze the factors influencing DS, and explore its role in post-treatment evaluation. Patients with suspected scabies were randomly divided into 2 groups: 71 patients in the skin scraping (SS) group and 73 patients in the DS group. The diagnostic efficiencies of SS and DS in these groups were calculated. We also analyzed the influence of body part and investigator competence on the accuracy of DS. Then 16 body parts with typical signs of scabies were monitored by DS 2 and 4 day after sulfur ointment treatment. The sensitivity and specificity of DS were 98.3% and 88.5%, respectively. Hands, arms, and the abdomen had higher positivity rates than other body parts (<i>P</i><0.001). The accuracy of dermatologists’ interpretations of images negative for scabies in the intermediate- and high-level groups was higher than that in the low-level group (<i>P</i><0.001). At follow-up, the mites were still visible on 43.8% to 62.5% of the skin lesions 2 and 4 day after sulfur ointment treatment. These results showed that DS could significantly increase the accuracy of diagnosing scabies owing to its high sensitivity and specificity. Therefore, it may be useful for monitoring clinical responses to anti-parasitic treatment.

Dermoscopy of skin parasitoses, bites and stings: a systematic review of the literature

“…Subsequent studies displayed superiority of dermoscopic examination vs skin scraping in terms of sensitivity (43.5-98.3% vs. 43.5-51.7%) but not in specificity (46-88.5% vs. 100%). 16,19,30,31 The same has been demonstrated when comparing dermoscopy with reflectance confocal microscopy (95% vs. 92% sensitivity and 97% vs. 100% specificity, respectively). 32 Of note, Park et al 21 analysed dermoscopy combined with skin scraping vs skin scraping alone and found a significant difference in accuracy in favour of the former (84% vs. 47%).…”

“…In a study by Micali et al ., 11 high‐magnification videodermoscopy (up to ×1000) was found to have a comparable diagnostic accuracy to skin scraping in recognizing scabies. Subsequent studies displayed superiority of dermoscopic examination vs skin scraping in terms of sensitivity (43.5–98.3% vs. 43.5–51.7%) but not in specificity (46–88.5% vs. 100%) 16,19,30,31 . The same has been demonstrated when comparing dermoscopy with reflectance confocal microscopy (95% vs. 92% sensitivity and 97% vs. 100% specificity, respectively) 32 .…”

Bullous Scabies: Clinical, Dermoscopic, and Pathologic Characteristics of Ten Patients

“…Previous studies revealed that dermoscopy is helpful for diagnosing scabies and has high sensitivity (98.3%) and specificity (97%). 14,15 Of the 10 patients in this study, five underwent dermoscopy tests for scabies, and the positive "jet with contrail" sign was noted in all patients. Therefore, dermoscopy should be a priority for screening patients with suspected scabies.…”

Common pediatric infestations: update on diagnosis and treatment of scabies, head lice, and bed bugs

“…However, the diagnostic utility of this technique is in question given its low sensitivity (46%) and the discomfort it may cause in infants and young children [9]. Noninvasive diagnostic techniques have emerged that allow for more rapid diagnosis of scabies, including, dermoscopy, videodermatoscopy, reflectance confocal microscopy, and optical coherence tomography [10][11][12]. The high sensitivity (83%) and ease of use of dermoscopy, in particular, makes it a promising tool in the diagnosis of scabies [12].…”

“…Noninvasive diagnostic techniques have emerged that allow for more rapid diagnosis of scabies, including, dermoscopy, videodermatoscopy, reflectance confocal microscopy, and optical coherence tomography [10][11][12]. The high sensitivity (83%) and ease of use of dermoscopy, in particular, makes it a promising tool in the diagnosis of scabies [12]. However, dermoscopy and other noninvasive techniques are costly, time consuming, and operator dependent, making them less useful in a primary care setting.…”