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

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.