Objective   

Develop, in collaboration with patients, a self-questionnaire measuring the severity of chronic pruritus in psoriasis, atopic dermatitis, seborrheic dermatitis of the scalp or idiopathic dermatitis, and its impact on quality of life

Methodology 

1^st version of the questionnaire developed in French following 3 main stages: 

• Definition of a conceptual framework based on a review of the literature and the expertise of physicians specializing in chronic pruritus; 
• Relevance of conceptual framework confirmed through focus groups (N=19); Drafting of questions and assessment of patients' understanding using individual semi-structured interviews (N=21 additional patients)
• Observational study conducted to reduce the number of questions in order to reduce the risk of non-response bias (N = 251 adult patients)

Results

• 1^st version of the questionnaire: highlighted items that did not appear in the literature, such as shame experienced by patients suffering from chronic pruritus and resignation in the face of pruritus
• Observational study: 
  • The quality of the answers to the questions was good. Very few items were missing, with the exception of 3 (2 on sexuality and 1 on work). A floor effect was identified for 9 items, including fatigue, sadness and loss of self-confidence
  • Internal consistency was good (Cronbach's α=0.94)
  • 3 main dimensions were identified in the scree plot and after varimax rotation
  • All items correlated well with the total score. The distribution of total score and VAS score was similar. All results were comparable between the two age groups
  • 13 questions were removed from the first version of the questionnaire. Clinical expertise enabled us to remove 6 other questions deemed redundant, resulting in a questionnaire comprising 20 questions

Conclusion

A 20-question self-questionnaire was developed in accordance with current international guidelines to measure the severity of chronic pruritus and its impact on quality of life