Development and Validation of the Fingertip Unit for Assessing Facial Vitiligo Area Scoring Index (F-VASI)

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Journal of the American Academy of Dermatology


BACKGROUND: Facial involvement of vitiligo is an important factor in patient's life and has often been evaluated separately from body surface area in clinical trials. However, no reliable measurement tools to measure facial vitiligo specifically are available thus far.

OBJECTIVE: To develop and validate a practical instrument for assessing facial vitiligo METHODS: The ratios of a hand to a fingertip unit (FTU) of 98 healthy volunteers (age range: 2-69 years) were calculated to define the FTU. Facial Vitiligo Area Scoring Index (F-VASI) was measured as the sum of all FTUs of each vitiligo lesion on the face (range: 0-112 FTU). In the validation study, 6 raters evaluated 11 patients with facial vitiligo twice at an interval of 2 weeks.

RESULTS: One hand was measured at 32.1±1.3 FTU, and it was highly consistent among subjects across different age groups, genders, and races. F-VASI showed remarkably high accuracy (concordance correlation coefficient: 0.946, smallest detectable change: 2.2 FTU) as well as high intra-rater reliability (intraclass correlation coefficient: 0.903) and inter-rater reliability (0.903).

LIMITATIONS: Lack of dynamic validation of responsiveness.

CONCLUSION: F-VASI using the FTU is an intuitive, precise, and reliable instrument for assessing the extent of facial involvement in vitiligo patients.

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ePub ahead of print