Development of a Visual Extension of the Severity of Alopecia Tool (VESALT) for Alopecia Areata

Alopecia areata (AA) presents with a broad range of clinical patterns that involve the scalp, eyebrows, eyelashes and beard. Accurate measurement of disease extent is essential for clinical care and study endpoints.1, 2 The Severity of Alopecia Tool (SALT) remains the current standard but excludes non-scalp regions and does not adjust for concomitant androgenetic alopecia (AGA).2 SALT depends on unguided visual estimation, which contributes to variability between observers. To address these limitations, we developed a visual extension of SALT (VESALT) and conducted a multi-step validation study using both live and photographic assessments. VESALT provides structured panels of reference images covering graded involvement of the scalp, eyebrows, eyelashes and beard. The scalp series reflects patchy, focal, ophiasis, reticulate and diffuse patterns that allow pattern recognition to be integrated into scoring. A graded density scale supports follow-up by accounting for partial regrowth. VESALT contains separate AGA panels with a correction formula that isolates autoimmune loss from hormonal thinning. First, 10 consecutive AA patients were examined in person by three observers who independently scored SALT and VESALT. Second, a photographic dataset of 53 cases was scored by 11 observers (Figure 1). This group included dermatologists, dermatology trainees, research staff and general practitioners. The photographs represented various phototypes and severities. Not all images were standardized, which reflects common clinical practice. Beard pictures were later standardized in a second scoring round. Across all analyses, VESALT produced excellent interrater reliability. In the live cohort, the intraclass correlation coefficient (ICC) reached 0.975. In photographic scoring, the ICC was 0.953 in the first round and 0.948 in the second round. Intrarater reliability was significantly higher for VESALT than for SALT (ICC 0.957 vs. 0.925). Nonetheless, the numerical correlation between the mean SALT and mean VESALT values exceeded 0.99. Bland–Altman analysis showed no systematic or proportional bias between methods. VESALT showed slightly higher intrarater ICCs and reduced visual dispersion between raters in repeated measures, although both instruments demonstrated excellent repeatability.3 Eyebrow and eyelash scoring achieved ICC values above 0.85 in live and photographic evaluations. Beard scoring showed ICC 0.865 in live assessments and 0.947 with standardized images. For patients with AA and AGA, the adjusted alopecia areata score reached ICC 0.967. Pattern identification had 94% agreement across raters, which suggests that pattern recognition can be successfully integrated into a structured scoring workflow. The smallest detectable differences (SDD) were comparable between VESALT and SALT for interrater reliability. The intrarater SDD was lower for VESALT compared to SALT (14.7% vs. 22.52%, respectively), although the clinical relevance of this difference warrants further study. Observers rated VESALT as more user-friendly and intuitive. Details on time to completion and learning curves will be addressed in future work together with responsiveness to treatment, which is essential for clinical trials. Although the live cohort was small, this sample size is commonly used in early reliability studies of scalp scoring instruments and allowed direct comparison with SALT under real clinical conditions.4-6 Regulatory guidance from agencies such as EMA and FDA increasingly emphasizes the need for reproducible and validated outcome measures.7 Because VESALT is numerically interchangeable with SALT, it can be used with established endpoints such as SALT50 and SALT90.3 The extended anatomic coverage and structured reference panels may allow more consistent scoring in multicentre studies (Figure 2). This study is limited by its monocentric design and sample size, and reliability differences between SALT and VESALT should therefore be interpreted with caution. The availability of both a paper version and an online VESALT calculator (www.alopecia-areata-calculator.com) also supports application in teledermatology and offers a framework for future automated image analysis and AI-based scoring research.8, 9 The research activities of R. Speeckaert and N. van Geel are supported by the Scientific Research Foundation-Flanders (FWO Senior Clinical Investigator: 18B2721N and 1831512N, respectively). The research activities of R. Speeckaert and N. van Geel are supported by the Special Research Fund (Bijzonder Onderzoeksfonds, BOF) of Ghent University and Ghent University Hospital. Reinhart Speeckaert MD, PhD received grants and/or honoraria from AbbVie, Almirall, Bristol Myers Squibb, Eli Lilly, Incyte, Janssen, Leo Pharma, Novartis, Pfizer, Pierre Fabre, UCB and Sanofi and involved in the development of several measurement instruments for vitiligo. Nanja van Geel MD, PhD received grants, is a consultant and/or investigator for AbbVie, Bristol Myers Squibb, Idorsia, Incyte, Leo Pharma, Merck/MSD, Novartis, Pfizer, and Sun Pharma and is chair of the Vitiligo Task Force for the European Academy of Dermatology and Venereology (EADV). She was involved in the development of several measurement instruments for vitiligo. All other authors (Arno Belpaire, Elise van Caelenberg, David Dewaele, Lise Vanden Broucke, Isabelle Hoorens, Laryssa Neudakh, Els Van Maelsaeke, Marijn Speeckaert) declare no conflict of interest. All procedures involving human participants were conducted in accordance with the ethical standards of the institutional and/or national research committee and with the Declaration of Helsinki. This study was approved by the Ethics Committee of UZ Gent. Written informed consent was obtained from all participants prior to inclusion in the study. The data that support the findings of this article are available upon reasonable request from the corresponding author.