Introduction: Alopecia areata (AA) is a non-scarring autoimmune disease characterized by patchy hair loss. The aim of this study was to validate a novel trichoscopic scoring tool, the Severity TRichoscopy Index for Alopecia Areata (STRIAA), for rapid assessment of AA severity. Methods: Anonymized images from 340 patients were scored by two independent raters who analyzed four scalp areas (vertex, occipital, and left and right parietal) for trichoscopic signs: black dots, yellow dots, exclamation mark hairs, broken hairs, and short vellus hairs. Scores (0–3) were assigned according to the number of trichoscopic signs per area, resulting in a total STRIAA score out of 60. Results: STRIAA showed high interrater reliability (Cronbach’s alpha 0.99) and significant correlation with the Severity of Alopecia Tool (SALT) score (p < 0.001). Yellow and black dots were significantly associated with the SALT score. Conclusions: The STRIAA provides a rapid and comprehensive assessment of AA severity, complementing current assessment tools in clinical practice
