Sutaria N, Alphonse MP, Marani M, et al. - In view of significant clinical heterogeneity in the presentation of prurigo nodularis (PN), this study unveiled disease endotypes.

• PN patients (n=20) and matched healthy controls were included, in whom circulating plasma cytokine levels were assayed.

• Two distinct clusters were revealed: PN patients with non-inflammatory (Cluster 1) and inflammatory (Cluster 2) plasma profiles.

• In Cluster 2, there were more African-Americans, higher worst-itch numeric rating scale scores, and lower quality of life as indicated by higher Dermatology Life Quality Index scores.

• Higher levels of IL-1α, IL-4, IL-5, IL-6, IL-10, IL-17A, IL-22, IL-25, and IFN-α were detected in Cluster 2 vs Cluster 1.

• Higher erythrocyte sedimentation rate, C-reactive protein, ferritin, eosinophils, and lower transferrin were found in African-American PN patients vs Caucasian PN patients.

• Overall, discrete clusters of PN patients exist with plasma biomarker profiles corresponding to distinct demographic and clinical features.