In vivo differentiation of scarring alopecia using line‐field confocal optical coherence tomography: a pilot study

Summary Background and Objectives : Diagnosing cicatricial alopecia is challenging. Even with histology, a definitive diagnosis cannot always be made. Line‐field confocal optical coherence tomography (LC‐OCT), a non‐invasive imaging method with high resolution used in vivo, has proven helpful in diagnosing scarring alopecia. This study aims to evaluate the potential of LC‐OCT for the differential diagnosis of different types of scarring alopecia. Patients and Methods : Images of 30 patients with scarring alopecia (10 Lichen planopilaris/Frontal fibrosing alopecia (LPP/FFA), 10 lupus erythematosus, 10 folliculitis decalvans/Folliculitis et perifolliculitis capitis suffodiens et abscedens (FD/FSA)) and 10 healthy controls were analyzed by two blinded independent examiners. Characteristic features and differential diagnoses were determined for each case. Results : LC‐OCT revealed distinct characteristics for each of the four subgroups, facilitating differential diagnosis with 100% sensitivity for lupus and 90% for LPP/FFA, FD/FSA, and the control group, and 100% specificity for LPP/FFA and 96.7% for the other groups. The features were used to generate a diagnostic algorithm tree. Conclusions : With LC‐OCT, specific criteria can be used to differentiate between subtypes of scarring alopecia. These preliminary findings provide a basis for hypothesis generation, which should be further explored in larger cohorts and in longitudinal studies assessing treatment response over time.