Supplementary Material for: Alopecia Areata Progression Index, a Scoring System for Evaluating Overall Hair Loss Activity in Alopecia Areata Patients with Pigmented Hair: A Development and Reliability Assessment

Background: No scoring systems to evaluate overall hair loss activity in alopecia areata (AA) have been established. Objective: We sought to develop a measurement tool (Alopecia Areata Progression Index, AAPI) for the evaluation of overall hair loss activity in AA patients with pigmented hair. Methods: The scalp surface area was divided into 4 quadrants. In each quadrant, hair loss activity was scored on the basis of the percentage of alopecic area, clinical findings associated with hair loss. The AAPI was measured in 17 patients with different severities of AA. Results: Interobserver and intraobserver reliabilities were assessed by 4 investigators. A significant correlation of the total AAPI was found among the 4 investigators. In addition, intraobserver reliability was excellent, and interobserver reliability was statistically reliable. Conclusion: The AAPI seems to represent a system capable of truly quantifying overall hair loss activity in AA patients with different severity, demonstrating trustworthy interobserver and intraobserver reliability.