Non-invasive Assessment and Management of Folliculitis Decalvans by Trichoscopy and Reflectance Confocal Microscopy.

Introduction: Folliculitis decalvans (FD) is a rare scarring alopecia mainly affecting middle-aged men, characterized by recurring episodes of follicular pustules, crusts, erythema, tufted hairs, and scars. Objectives: This study investigates the effectiveness of reflectance confocal microscopy (RCM) compared to trichoscopy for diagnosing and monitoring FD. Methods: The study involved 24 Caucasian patients diagnosed with FD. Patients were examined using trichoscopy and RCM, with a focus on specific features like erythema and inflammatory cell distribution. A subgroup of 16 patients was followed up after 3 months of therapy. The reproducibility of RCM and trichoscopy was assessed using Cohen Kappa Test. Results: RCM and trichoscopy consistently detected features such as tufted hairs, pustules, and perifollicular fibrosis. However, RCM provided more detailed insights into inflammatory activity and types of fibrosis, often overlooked by trichoscopy. It showed a reduction in vessels and inflammatory cells, which trichoscopy failed to detect. The concordance between RCM evaluations was excellent, indicating high reproducibility.