OBJECTIVES: Vitiligo is an autoimmune depigmentation disorder that affects patients’ appearance and health related quality of life. This research evaluated the content validity of the Self-Assessment Vitiligo Extent Score (SA-VES) measure.

METHODS: The SA-VES assesses extent of vitiligo-related body surface area (BSA) depigmentation, on a 7-point pictorial scale ranging from no involvement to most involvement, in 12 body locations. This study consisted of in-person qualitative interviews with adolescents and adults with vitiligo. Participants completed the measure on an electronic tablet device and were debriefed about their understanding of the SA-VES items (comprehensibility), conceptual relevance, suitability of response options, and the ease of tablet use.

RESULTS: The study included twenty adults and ten adolescents, aged 13-77 years, predominantly non-segmental vitiligo (n=23, 76%) and Fitzpatrick skin type I-III (n=24, 80%). Clinician-reported vitiligo BSA involvement ranged from 4-70%. The SA-VES was generally well received, with participants reporting high levels of item understanding (n=29/30, 96%), conceptual relevance (n=26/30, 86%), suitability of response options (n=27/30, 90%), and ease of tablet use (n=25/30, 83%). However, some limitations related to the understanding of the written instructions were observed, with participants selecting responses based on lesion location rather than extent of the lesions. Revised instructions were tested with six participants and improved understanding in most (n = 4/6, 66%). The interviews also revealed that in a few items, some body parts were pictured in the response options but were not specifically named in the question. This may have caused confusion when selecting responses.

CONCLUSIONS: For adolescents and adults with vitiligo, the SA-VES pictorial scale was well-understood, conceptually relevant, and easy to complete using a tablet. Following discussions with a vitiligo clinical expert, six item labels were amended for clarification. With some modifications and testing, the SA-VES may be suitable for assessing patient-reported vitiligo BSA involvement in clinical research.