Clinical and Laboratory Characterization of Vellus Follicle and Epidermis Involvement in the Face, Neck, and Upper Chest in Frontal Fibrosing Alopecia

The study investigated the involvement of skin and hair in the face, neck, and upper chest in patients with alopecia frontal fibrosante (AFF). It included 37 patients for clinical and dermatoscopic evidence, 20 patients and 20 controls for epidermal thickness evaluation, and 21 patients and 21 controls for confocal microscopy analysis. Results showed that facial vellus hair involvement varied from 30% to 97% depending on the region, with papules found in 60% of patients, primarily in the temporal region. Hyperchromic lesions, compatible with lichen planus pigmentosus, were less common in patients with lower phototypes. No difference in epidermal thickness was found between AFF patients and controls. A follicular density of less than 3.56 follicles/mm² at the frontal hairline had high sensitivity and specificity for AFF diagnosis, indicating a significantly increased risk of the disease. Dermatoscopy was effective for non-invasive detection of facial hair involvement.