Questionnaire Modifications and Alternative Scoring Methods of the Dermatology Life Quality Index: A Systematic Review

The systematic review identified 59 modifications of the Dermatology Life Quality Index (DLQI) across 77 studies involving 25,509 patients from 28 countries, addressing 47 different diagnoses and symptoms. The modifications included bolt-ons/bolt-offs (48%), disease/symptom/body part specifications (42%), changes in existing items (34%), scoring modifications (27%), recall period changes (19%), response scale modifications (15%), and illustrations (3%). The psychometric quality of these modifications varied, with positive ratings in internal consistency (4/13 studies), reliability (1/3), content validity (3/5), construct validity (9/22), criterion validity (6/6), and responsiveness (1/1). The findings suggested a significant need for better-validated health-related quality of life instruments in dermatology.