Reflectance Confocal Microscopy and Line-field Confocal Optical Coherence Tomography in Hair Loss: a Systematic Review and a Glossary of Nomenclature

Background Reflectance confocal microscopy (RCM) and line-field confocal optical coherence tomography (LC-OCT) are emerging non-invasive imaging techniques in hair loss, potentially bridging the diagnostic gap between trichoscopy and histopathological examination. Objective To systematically summarize RCM and LC-OCT features across cicatricial and non-cicatricial alopecias. Methods This systematic review was conducted according to PRISMA 2020 guidelines and was registered in PROSPERO (CRD420251134481). MEDLINE and Embase were searched from inception to 28 February 2026. Eligible studies included original studies and case reports of RCM and/or LC-OCT in hair loss. Results Forty-one studies encompassing 517 patients were included in the qualitative synthesis. Cicatricial alopecias showed higher pooled prevalence of dilated vessels, exocytosis, adnexal inflammatory infiltrates, and periadnexal sclerosis, whereas rimmed dermal papillae and hair shaft miniaturization predominated in non-cicatricial forms. Evidence for treatment monitoring was limited but promising. A harmonized glossary linking RCM and LC-OCT features to trichoscopic and histopathological correlates was proposed. Limitations This review is limited by the relatively low number of included studies and lack of standardized reporting of imaging features. Conclusion RCM and LC-OCT are valuable adjunctive tools in hair loss diagnostics and may aid differentiation between cicatricial and non-cicatricial forms.