Concordance among in vivo reflectance confocal microscopy, trichoscopy, and histopathology in the evaluation of scalp discoid lupus

Background Reflectance confocal microscopy (RCM) has been used for the evaluation of several inflammatory skin conditions, including skin discoid lupus erythematosus (DLE), and has been correlated with conventional histopathology (HP). However, RCM is not being widely used in trichology. Few reports and just preliminary data suggest the use of RCM as a complementary tool in alopecias.Objectives To correlate the major RCM features of scalp DLE with trichoscopy and HP findings of biopsy specimens obtained from the same lesions.Methods This is an observational, analytical, and cross-sectional study involving 12 patients with a clinically established diagnosis of scalp DLE. Patients underwent global clinical photograph, trichoscopy, and RCM examination in the same site followed by two 4-mm punch biopsy specimens for HP analysis. Inter-methods agreement among RCM imaging, trichoscopy, and horizontal histopathology sections (HHS) were calculated using Cohen Kappa (k) statistics.Results Statistical analysis of the agreement between RCM and HP features disclosed an overall agreement similar to skin DLE. Seven of the eleven features evaluated had agreement superior to 75%. We also evaluated RCM features associated with three of their corresponding trichoscopic findings for further investigation of their agreement with HP. Statistical analysis showed an enhancement with agreement of 86% when the non-invasive techniques are used together.Conclusion Consistent correlation between RCM and HP observed in our study supports the reliability of RCM in the diagnosis of scalp DLE. RCM may be considered a promising tool for scalp DLE microscopic evaluation and presents similar RCM features to DLE in other body sites. By associating clinical, trichoscopic and RCM evaluation, dermatologists will have a non-invasive arsenal for the assessment of hair and scalp disorders, benefiting patients.