The burden of psoriasis is not determined by disease severity only

Psoriasis is a chronic scaling and inflammatory skin disease that can affect patients' quality of life and daily functioning. We studied the scores of 85 patients suffering from moderate to severe plaque-type psoriasis, participating in a randomized controlled trial. We compared their scores on a generic quality-of-life instrument with data from two reference populations. We examined associations between clinical severity, as measured by the components of the Psoriasis Area and Severity Index (PASI), and the respective quality-of-life subdimensions, measured by the Medical Outcome Survey Short Form 36 (SF-36), to find out what elements of disease activity are related with impaired quality of life. Compared to the reference population, quality of life was impaired in terms of bodily pain and social functioning. There were no significant correlations between overall disease severity, as measured by PASI, and the SF-36 subdimensions. When examining the PASI components, we found significant correlations between desquamation on the upper limbs and mental health and bodily pain (r = -0.23 and r = -0.28, respectively) and between desquamation on the scalp and mental health (r = -0.29). In conclusion, we found that psoriasis patients had a lower quality of life than a reference population, without a significant relation between disease severity or disease area and quality of life. Yet psoriasis lesions located on visible body parts are significantly correlated with aspects of quality of life.