Skin disease can cause severe disability and handicap in children. Measurement of the impact of skin disease on the quality of life is required to aid clinical decision-making, for clinical research, for audit of paediatric dermatology services, and for political reasons, to aid arguments for more resources for the care of children with skin disease. Adult measures are inappropriate, as the lives of children differ markedly from those of adults. The purpose of this study was to create and initially validate a simple practical questionnaire for use in children. One hundred and sixty-nine children, aged 3-16 years, attending a paediatric dermatology clinic, wrote down, with the help of their parents, all the ways in which their skin disease affected their lives. One hundred and eleven different aspects were identified; 10 questions were composed to cover these aspects, using a structure similar to the Adult Dermatology Life Quality Index. This draft questionnaire was piloted on two series, totalling 40 children, and minor alterations were made to improve clarity. The Children's Dermatology Life Quality Index (CDLQI) questionnaire (maximum score 30) was then given to a further 233 dermatology paediatric out-patients (CDLQI mean = 5.1, SD = 4.9), 47 normal controls (mean 0.4, 0.7) and 55 control patients attending a general paediatric clinic (mean 0.7, 2.5). The CDLQI scores for eczema (mean = 7.7, 5.6, n = 47), psoriasis (5.4, 5.0, n = 25) and acne (5.7, 4.4, n = 40), were all highly significantly greater than for moles and naevi (2.3, 2.9, n = 29). The highest mean score was that for scabies (mean = 9.5, 10.5, n = 6).(ABSTRACT TRUNCATED AT 250 WORDS)