Ultraviolet photography in vitiligo: image quality, validity and reliability

For clinical care and research in vitiligo, photographs with the use of ultraviolet (UV) light or Wood's lamp are often made. Conventional cameras are insensitive to UV light. The use of a UV camera (UV photography) might improve image quality and ameliorate the assessment of target lesions in vitiligo.

To determine image quality and the validity and reliability of UV photography for the assessment of vitiligo target lesions.

Images of patients with vitiligo were made with UV photography and a conventional camera, and lesions were drawn on graph paper and transparent sheets. Image quality was scored by vitiligo experts and medical interns. The intraclass correlation coefficients (ICCs) of the lesion size determined with UV photography combined with digital surface measurement and the other techniques were hypothesized to be above 0.6. The ICCs between UV images taken by the same physician and between two different physicians were calculated for determining inter- and intra-reliability.

In total, 31 lesions of 17 patients were included. Image quality was assessed as good or very good for 100% and 26% for UV photography and the conventional camera, respectively. ICCs of UV photography and the conventional camera, drawing the lesions on transparent sheets and graph paper, were 0.984, 0.988 and 0.983, respectively, confirming our hypotheses. The ICCs of the intra-rater and inter-rater were 0.999 and 0.998, respectively.

The results of this study indicate that the use of UV photography for the assessment of vitiligo lesions improves image quality and is valid and reliable.