The psychosocial impact of psoriasis may result in significant daily stress for the patient. We present a questionnaire, the Psoriasis Life Stress Inventory (PLSI), which provides a rating of psoriasis-related stress. Two hundred and seventeen psoriasis patients endorsed a list of psoriasis-related items they had experienced over the previous one month and rated the degree of stress associated with each item on a 4-point scale. The final version of the PLSI consisted of 15 items, each of which had been endorsed by at least 15% of patients. A PLSI score of > or = 10 (range 0 to 43) delineated patients with greater overall psoriasis severity (p = 0.007), more cosmetically disfiguring psoriasis (p < 0.01), greater number of flare-ups of psoriasis (p = 0.009) and greater pruritus severity (p = 0.001). This preliminary instrument provides a clinically useful index of psoriasis-related stress and needs to be tested among patients from different centers and in prospective studies.