The experience of itch in children with psoriasis: A qualitative exploration of the Itch Numeric Rating Scale

Background/objectives Psoriasis is a chronic, immune-mediated dermatologic disorder with a prevalence among children estimated at 0.1%-0.45%, and a median age of onset at approximately 7-10 years. Pediatric psoriasis is known to have negative impacts on health-related quality of life. Among the most bothersome symptoms, itch has been measured using the Itch Numeric Rating Scale (NRS). This study explored the symptom and impacts of itch with pediatric psoriasis patients and evaluated the content validity of the Itch NRS in children. Methods Semi-structured qualitative interviews were conducted among a sample of pediatric patients diagnosed with plaque psoriasis. Results Concept elicitation interviews were completed with 22 children (ages 7-17 years). When asked about most frequent symptoms, 61% reported itching (n = 14) and 65% reported flaking (n = 15). The majority reported itching as bothersome; about half described impacts on their regular activities. Cognitive interviews were completed with 25 children (ages 8-17 years). Most reported that independently completing the Itch NRS would be easy, and all described the meaning of the response options similar to the intended value. Overall, the Itch NRS was received favorably, with comments that the scale was easy or relevant to their experience with psoriasis. Conclusions This qualitative study supports the content validity of the Itch NRS for use in a pediatric psoriasis population aged 8-17. Given the established importance of itch to pediatric psoriasis patients, future research exploring the impact of itch on the lives of pediatric psoriasis patients may provide a valuable contribution to the field.