Dermatology quality of life scales--a measure of the impact of skin diseases.

Patient-generated dermatology quality of life scales (DQOLS) were developed to assess the impact of skin conditions on patients' psychosocial state and everyday activities. The items were derived from the self-reported impacts of their skin condition by 50 dermatology out-patients. The resulting 17 psychosocial items and 12 activities items were assigned five-point scales and self-completed by 118 out-patients. Factor analyses grouped the items into four psychosocial subscales (embarrassment, despair, irritableness, distress) and four activities subscales (everyday, summer, social, sexual). Tests of the psychometric properties indicated that the internal consistency of responses was high, with Cronbach's alpha coefficients of 0.92 for the 17 psychosocial items and 0.83 for the 12 activity items. Assessment of reliability based on 41 psoriasis patients attending phototherapy treatment identified good short-term test-retest reliability, with intraclass correlation coefficients of 0.84 for both the psychosocial and activities scales. Construct validity was confirmed by the ability of the scales to identify clinically expected differences and their greater sensitivity to the impacts of skin problems compared with a widely used generic health status measure. The DQOLS thus form a robust measure of patient-perceived impacts. They were quickly self-completed and provide information that complements traditional clinical indicators. These scales should assist in informing treatment decisions by identifying impacts of different skin conditions and variations in responses among social and cultural groups, as well as guiding priorities for services within the specialty.