Severity Scorings for Prurigo Nodularis With Review of Treatment Outcome in 22 Cases

Pruritic lesions, including prurigo nodularis (PN), represent chronic and often refractory disease. Existing severity scorings for PN are challenging to use effectively and need improvement to accurately assess disease severity and treatment efficacy. Additionally, effective treatment options for PN remain limited. To assess the correlation between existing and newly proposed severity scorings, evaluate the usefulness of these new severity scorings, and review the treatment outcomes in patients with PN. This study included 22 patients with PN. As newly proposed severity scorings, we tested the number (termed the "breaking-number") and the rate (termed the "breaking-rate") of nodules on the state of "self-destruction (erosion or ulcer)" as a result of scratching due to severe itching. Spearman's correlation coefficient was used to assess the correlations. We also had statistics on the correlation between these severity scorings and some blood test findings (serum thymus and activation regulated chemokine levels, serum immunoglobulin E levels, serum lactate dehydrogenase levels, the blood eosinophil count, and the blood basophil count). The breaking-number correlated with the Worst Itching Intensity Numerical Rating Scale (WI-NRS) and Investigators Global Assessment for PN Stage (IGA PN-S) scores (p < 0.05), and the breaking-rate correlated with WI-NRS score (p < 0.05), but not with IGA PN-S score (p ≥ 0.05). Only the blood basophil count correlated with the breaking-number, breaking-rate, and the IGA PN-S score (p < 0.05). The breaking-number and breaking-rate could be used to assess the severity of PN. We hope these severity scorings will lead to quick and accurate assessment of disease severity and treatment efficacy.