부산대학교 도서관

Background: Facial involvement in vitiligo patients is one of the most critical factor that affects negatively on patient’s quality of life, but no reliable measurement tool for facial vitiligo is available so far. Objectives: To devise the fingertip unit (FTU) as an intuitive and practical measurement unit for facial vitiligo, and to develop and validate the Facial Vitiligo Area Scoring Index (F-VASI) using the FTU. Methods: The images of 98 healthy volunteers’ hands were analyzed to establish the FTU as a measurement tool. The validation study of F-VASI was conducted with 41 dermatologists on 17 images of facial vitiligo. Results: In the image analysis of volunteers’ hands, we found that one palm corresponds to 18 FTU, and one hand to 32 FTU. In the validation study, the F-VASI showed remarkably high accuracy (concordance correlation coefficient: 0.939, the smallest detectable change: 2.0 FTU) as well as high intra-rater reliability (intraclass correlation coefficient: 0.926) and inter-rater reliability (0.861). Conclusion: F-VASI is an accurate, reliable, and feasible instrument for assessing the extent of facial involvement in vitiligo patients. FTU can be used alone to sensitively assess small scattered lesions on the face, as well as to complement the hand unit to assess VASI for whole body vitiligo. It is relevant in that it reflects the fact that tiny white patches on the face are non-trivial for vitiligo patients.