Association of prurigo nodularis and infectious disease hospitalizations: a national cross-sectional study

Spatial Mass Cytometry-Based Single-Cell Imaging Reveals a Disrupted Epithelial-Immune Axis in Prurigo Nodularis

Prurigo nodularis (PN) is a chronic, inflammatory skin condition that disproportionately affects African Americans and features intensely pruritic, hyperkeratotic nodules on the extremities and trunk. PN is understudied compared with other inflammatory skin diseases, with the spatial organization of the cutaneous infiltrate in PN yet to be characterized. In this work, we employ spatial imaging mass cytometry to visualize PN lesional skin inflammation and architecture with single-cell resolution through an unbiased machine learning approach. PN lesional skin has increased expression of caspase 3, NF-kB, and phosphorylated signal transducer and activator of transcription 3 compared with healthy skin. Keratinocytes in lesional skin are subdivided into CD14+CD33+, CD11c+, CD63+, and caspase 3-positive innate subpopulations. CD14+ macrophage populations expressing phosphorylated extracellular signal-regulated kinase 1/2 correlate positively with patient-reported itch (P = .006). Hierarchical clustering reveals a cluster of patients with PN with greater atopy, increased NF-kB+ signal transducer and activator of transcription 3-positive phosphorylated extracellular signal-regulated kinase 1/2-positive monocyte-derived myeloid dendritic cells, and increased vimentin expression (P < .05). Neighborhood analysis finds interactions between CD14+ macrophages, CD3+ T cells, monocyte-derived myeloid dendritic cells, and keratinocytes expressing innate immune markers. These findings highlight phosphorylated extracellular signal-regulated kinase-positive CD14+ macrophages as contributors to itch and suggest an epithelial-immune axis in PN pathogenesis.

Diagnosing Atopic Dermatitis in Skin of Color

Atopic dermatitis (AD) is a pruritic inflammatory skin disease that disproportionately affects skin of color patients. African American, Asian, and Hispanic patients carry disproportionate disease burdens, with increased prevalence, disease severity, and health care utilization. AD has a unique clinical presentation in skin of color patients, often with greater extensor involvement, dyspigmentation, and papular and lichenified presentations. Erythema is also more difficult to appreciate and can result in an underappreciation of disease severity in skin of color patients. In this review, we highlight the important manifestations of AD across all skin types, including nuances in treatment.

Dupilumab in patients with prurigo nodularis: two randomized, double-blind, placebo-controlled phase 3 trials

Prurigo nodularis (PN) is a chronic inflammatory skin disease with intensely pruritic nodules. The LIBERTY-PN PRIME and PRIME2 phase 3 trials enrolled adults with PN with ≥20 nodules and severe itch uncontrolled with topical therapies. Dupilumab, a fully human monoclonal antibody, blocks the shared receptor component for interleukin (IL)-4 and IL-13. Patients were randomized 1:1 to 300 mg dupilumab or placebo subcutaneously every 2 weeks for 24 weeks. The primary endpoint was pruritus improvement, measured by proportion of patients with a ≥4-point reduction in Worst Itch Numeric Rating Scale (WI-NRS) from baseline at week 24 (PRIME) or week 12 (PRIME2). Key secondary endpoints included nodule number reduction to ≤5 at week 24. PRIME and PRIME2 enrolled 151 and 160 patients, respectively. Both trials met all the pre-specified primary and key secondary endpoints. A ≥4-point WI-NRS reduction at week 24 in the dupilumab and placebo arms was achieved by 60.0% and 18.4% of patients, respectively, in PRIME (95% confidence interval (CI), 27.8-57.7 for the difference, P < 0.001) and at week 12 by 37.2% and 22.0% of patients, respectively, in PRIME2 (95% CI, 2.3-31.2; P = 0.022). Dupilumab demonstrated clinically meaningful and statistically significant improvements in itch and skin lesions versus placebo in PN. Safety was consistent with the known dupilumab safety profile.ClinicalTrials.gov identifiers: NCT04183335 and NCT04202679 .

Cluster analysis of circulating plasma biomarkers in prurigo nodularis reveals a distinct systemic inflammatory signature in African Americans

Patients with prurigo nodularis (PN) suffer from intractable itch and dramatic reduction in quality of life. While there is significant clinical heterogeneity in the presentation of PN, disease endotypes remain unknown. We assayed circulating plasma cytokine concentrations in PN patients (n=20) along with matched healthy controls and utilized an unsupervised machine learning algorithm to identify disease endotypes. We found two distinct clusters of PN patients with non-inflammatory (Cluster 1) and inflammatory (Cluster 2) plasma profiles. Cluster 2 had more African-Americans (82%, n=9 vs. 33%, n=3; P=0.028), higher worst-itch numeric rating scale scores (9.5±0.9 vs. 8.3±1.2; P=0.036), and lower quality of life as reflected by higher Dermatology Life Quality Index scores (21.9±6.4 vs. 13.0±4.1; P=0.015). In addition, Cluster 1 had a higher rate of myelopathy (67%, n=6 vs. 18%, n=2; P=0.028). Compared to Cluster 1, Cluster 2 had higher levels of IL-1α, IL-4, IL-5, IL-6, IL-10, IL-17A, IL-22, IL-25, and IFN-α. With population-level analysis, African-American PN patients had higher erythrocyte sedimentation rate, C-reactive protein, ferritin, eosinophils, and lower transferrin than Caucasian PN patients. These findings indicate discrete clusters of PN patients with plasma biomarker profiles corresponding to distinct demographic and clinical characteristics, potentially allowing for precision medicine approaches to treat PN.

Clinical characteristics and disease burden in prurigo nodularis

BACKGROUND

Prurigo nodularis (PN) is a chronic inflammatory skin disease characterized by intense pruritus, but information on patient experience and impact on quality of life (QoL) remains understudied.

AIM

To characterize disease characteristics and QoL in a global sample of patients with PN.

METHODS

An anonymous survey was distributed via patient support groups for PN.

RESULTS

In total, 231 members responded to the survey. The majority of respondents reported itch localized both to nodules and to intervening skin (67.0%). Associated symptoms included prickling, pain, stinging and burning. The extensor lower legs (69% right, 67.3% left) and flexor forearms (66.1% right, 62% left) were the most common sites of itch. Participants reported frequent healthcare utilization, with 36.3% visiting a doctor ≥ 10 times in the past year. Physician-diagnosed anxiety (45.4%), depression (16.4%) and the atopic triad (18.7%) were commonly reported. Patients with PN had mean scores of 16.4, 11.6 and 16.8 on the Dermatology Life Quality Index, Pittsburgh Sleep Quality Index and 5-Dimensions Itch, respectively.

CONCLUSIONS

Severe pruritus with accompanying pain, stinging and burning is characteristic of PN, with the majority of patients experiencing itch in both nodular and interlesional skin. Patients further report decreased QoL scores and impaired sleep. Patient experiences should guide future management of PN.