The influences of diet on psoriasis have been long discussed. As reported in previous publications, a majority of U.S. psoriasis population show high interest in the role of diet on their skin conditions. Given the distinct traditional perceptions and lifestyles in China, the dietary beliefs and behaviors in Chinese psoriasis patients would be very likely to show different patterns. Nevertheless, the information of this large population is still unknown. In this regard, the investigators conduct a questionnaire-based survey, aiming to assess the dietary perceptions and behaviors of Chinese psoriasis patients.

A total of 25 medical institutions all over China participated in the survey. Psoriasis patients surveyed were from both outpatient and inpatient dermatology departments. Researchers from each institution were trained for assisting patients to fill the questionnaire. Each participant filled the online-based questionnaire anonymously in a private setting. The questionnaire consisted of 54 main questions and extended questions, concerning the profile of disease conditions, perceptions and behaviors of diet in their daily life.

Inclusion Criteria:

• Age ≥ 18 years old.
• Confirmed diagnosis of psoriasis.
• Duration of psoriasis ≥ 3 years.
• Must be able to read and understand the questionnaire.
• Receive a full explanation of the purpose and content of the trial before the study begins, and voluntarily sign a written consent form.

Exclusion Criteria:

• Unable to read or understand the questionnaire.
• Other conditions deemed by the investigator to be inappropriate for this study.

The survey is a nation-wide study conducted in 25 hospitals or institutions in China, aiming to observe the dietary perceptions and practices in Chinese adult psoriasis patients. The patient population covered 31 provinces and 241 cities over China.