Abstract: Objective: To determine the reflectance confocal microscopic (RCM) characteristics of classic lichen planopilaris and the significance in the diagnosis of lichen planopilaris. Methods: RCM observation and histomatological examination were performed in 24 patients suspected with classic lichen planopilaris in our hospital from January 2018 to June 2020. Results: The features of the RCM in 24 patients with classic lichen planopilaris  included epidermal atrophy in 9 cases (37.5%), hair follicle horn plug in 4 cases (16.67%), liquefaction degeneration of basal cells in 10 cases(41.67%),  superficial dermis infiltrated by single nuclear cells in 9 cases (37.5%), substrate cells liquefaction of hair follicle wall surrounded by single nuclear cells and melanophages in 24 cases(100%), and collagen hyperplasia around the hair follicles in 7 cases (29.17%), and the consistent rates of these features between RCM and histomatological examination were 91.67%, 83.33%, 91.67%, 96.43%, 100% and 83.33% respectively. Conclusion: The RCM characteristics of classic lichen planopilaris are highly consistent with the results of histopathological examination. RCM can provide effective help for the diagnosis and the judgment of therapeutic efficacy.of classical lichen planopilaris.

Key words: classical lichen planopilaris, histopathology, reflectance confocal microscopic