Data table

The present research was a questionnaire-based cross-sectional study. We included patients diagnosed with psoriasis who received treatment at Chulabhorn Hospital in Thailand from January 2019 to July 2021. The inclusion criteria were patients over 18 years old without any cognitive or related problems, such as delirium or dementia. Each patient responded to the questionnaire by telephone or face-to-face with a non-dermatologist interviewer to avoid any bias. Alternatively, patients could choose to complete and return the questionnaire via postal mail. Patients were informed that they could stop the interview at any point and could also refuse to participate in the study without any effect on their treatment in the future. We collected information on patients’ demographic data, current treatment, Itch Numeric Rating Scale (Itch NRS) scores, factors affecting itch, and scores on the Thai version of the Dermatology Life Quality Index (DLQI). For the assessment of itch intensity in this questionnaire-based study, we used the Itch NRS scale, a manual rating scale used to assess the intensity of pruritus, with scores ranging from 0 to 10. The Itch NRS was the instrument of choice because of our study design, its simplicity of assessment, and the high validity and high correlation with other manual rating scales, such as the visual analog scale (VAS) and verbal rating scale (VRS). Quality of life was evaluated using the validated Thai version of DLQI, a validated and widely used tool with a version available in Thailand 9.