Severity of scratching may be a useful endpoint in clinical trials and practice across the gamut of pruritic disorders, according to a recent study. Researchers sought to validate and test the severity of scratching as an objective measure of itch (4-point ordinal scale ranging from 0 [not present] to 3 [very prominent] based on the observation of scratching lesions). They performed a prospective outpatient study using questionnaires and evaluations by a dermatologist in adults with atopic dermatitis (AD) (n=261). Severity of scratching best correlated with patient-reported global AD severity (Kendal’s Tau=0.336), Numeric Rating Scale (NRS) of itch in the past 24 hours (0.266) and 3 days (0.296). They found:
- Severity of scratching showed responsiveness over time.
- Patient’s experiencing ≥1-point improvement of scratching severity had significantly lower NRS-itch in the past 3 days (Wilcoxon rank sum test), 5-D itch scale, and Patient Oriented Eczema Measure (POEM) scores.
- There was a significant decrease in scratching severity for patients experiencing ≥4-point improvement of NRS-itch in the past 3 days (Fisher’s exact test), POEM, and Dermatology Life Quality Index (DLQI).
Udkoff J, Silverberg JI. Validation of scratching severity as an objective assessment for itch. [Published online ahead of print December 11, 2017]. J Invest Dermatol. doi:10.1016/j.jid.2017.11.028.