Construction and validation of a photographic guide for assessing severity of chronic hand dermatitis

Background A standardized instrument is needed to rate the overall severity of chronic hand dermatitis (CHD), in particular during clinical trials. Objectives To design and validate a photographic guide. Methods Initially, five experts were asked to grade 50 photographs of CHD, first individually, then as a consensus-building group, in order to select the photographs included in the guide. Then, a validation session with 11 different dermatologists evaluating 28 patients was conducted to assess the interrater reliability and test-retest reproducibility of the assessment of disease severity, relying on the photographic guide, on two consecutive days. Patient order was randomized, and only diseased hands were visible to prevent any bias in evaluation. Results The experts reached a consensus for development of a photographic guide composed of five severity levels and four photographs per severity level. Results of the validation session showed a high level of interrater reliability and test-retest reproducibility. Conclusions The photographic guide is a reliable tool for assessing the morphological severity of hand dermatitis, and can be used as part of a comprehensive evaluation of disease in international multicentre clinical trials.