Prurigo nodularis: Pathogenesis and management

Exploration of potential biomarkers for prurigo nodularis based on plasma-metabolome analysis

Prurigo nodularis (PN) is a chronic and debilitating skin disease with severe itching that negatively impacts patients' quality of life and mental state. However, the treatment options for PN remain limited. Global metabolomics analysis can offer effective information on energy metabolism, pathogenesis and potential diagnostic biomarkers. No study on metabolomic analysis of PN has been reported. To further understand the mechanisms of PN and analyse the plasma metabolite profiles in patients with PN. Targeted-metabolome analysis of 306 metabolites in plasma from 18 patients with PN and 19 healthy controls was performed using Liquid Chromatography-tandem Mass Spectrometer analysis. We identified 31 differential metabolites. Most acylcarnitines, long-chain fatty acids, alpha-aminobutyric acid, hydroxybutyric acid and lactic acid among these metabolites were up-regulated in patients with PN; in contrast, glucaric acid, suberic acid, bile acid derivatives and most amino acids were down-regulated. Positive correlations exist between glucaric acid and itching severity and acylcarnitines and insomnia. Suberic acid and the Investigator's Global Assessment (IGA) scores correlate negatively. Metabolite variation reflects the dysregulation of energy metabolism and chronic systematic inflammation in PN. Several metabolites, such as glucaric acid, suberic acid and acylcarnitines, merit further study as potential biomarkers of disease severity in PN.

Pathophysiology of Prurigo Nodularis: Neuroimmune Dysregulation and the Role of Type 2 Inflammation

Prurigo nodularis (PN) is a chronic, inflammatory skin condition characterized by multiple, intensely pruritic, distinctive nodular lesions. Subsequent scratching can further intensify the pruritus, culminating in a self-reinforcing itch-scratch cycle, which drives lesion development. The latest data indicate dysregulation of the neuroimmune axis in PN pathogenesis, including the involvement of sensory neurons, key effector immune cells, proinflammatory cytokines, dermal fibroblasts, and pruritogens. In this review, we highlight evidence supporting the role of type 2 immune axis dysregulation in driving the clinical presentation of PN and discuss how related signaling pathways may offer effective therapeutic targets to control PN signs and symptoms.

Depression, Anxiety and Suicidal Ideation in Prurigo Nodularis: A Systematic Review and Meta-analysis

Abstract is missing (Short communication)

[Treatment of chronic prurigo: update and perspectives]

BACKGROUND

Despite the high burden in patients with chronic prurigo (CPG), the first and so far only approved systemic therapy for this disease, dupilumab, has only been available since 2022. Therefore, treatment is mostly based on expert recommendations for off-label therapies. We aim to provide an overview of current therapies and possible future therapeutic drugs for CPG patients, which are currently in clinical trials.

MATERIALS AND METHODS

For this review, a systematic literature and clinical trial search was conducted via PubMed and Clinical Trials using the terms "chronic prurigo", "chronic nodular prurigo", "prurigo nodularis" and "therapy".

CONCLUSION

Multiple new therapeutic agents are currently under investigation in clinical trials, providing promising results for future treatment options. Moreover, an annotated checklist was developed recently to improve therapeutic decision-making in daily clinical practice with CPG patients.

A Fleshy Mystery: Prurigo Nodularis

Prurigo nodularis is a chronic dermatologic condition typically presenting as firm, dome-shaped pruritic nodules of various sizes that are often symmetrically distributed on extensor surfaces of the extremities. The diagnosis is clinical and based on a history of chronic, severe pruritis in the setting of characteristic, excoriated lesions. Treatment is difficult and aimed at reducing skin irritation and pruritus. Quality of life is impacted due to the chronic, intractable, and relapsing nature of the disease. Here, we report a case of prurigo nodularis diagnosed in the outpatient clinic setting. This paper aims to report the patient's clinical history, presentation, and histopathologic findings, as well as present a literature review to determine the significance of this case and the approach to ongoing management.

Efficacy and Safety of Abrocitinib in Prurigo Nodularis and Chronic Pruritus of Unknown Origin: A Nonrandomized Controlled Trial

Importance

Prurigo nodularis (PN) and chronic pruritus of unknown origin (CPUO) are chronic pruritic diseases that dramatically impair quality of life, but therapeutic options are limited. Abrocitinib, a Janus kinase 1 inhibitor, represents a promising therapy for both conditions.

Objective

To assess the efficacy and safety of 200-mg oral abrocitinib administered once daily in adults with moderate to severe PN or CPUO.

Design, Setting, and Participants

This phase 2, open-label, nonrandomized controlled trial conducted between September 2021 and July 2022 took place at a single center in the US. A total of 25 adult patients with moderate to severe PN or CPUO were screened. Ten patients with PN and 10 patients with CPUO were enrolled. All 20 patients completed the 12-week treatment period, 18 of whom completed the 4-week follow-up period.

Intervention

Abrocitinib, 200 mg, by mouth once daily for 12 weeks.

Main Outcomes and Measures

The primary efficacy end point was the percent change in weekly Peak Pruritus Numerical Rating Scale (PP-NRS) scores from baseline to week 12. Key secondary end points included the percentage of patients achieving at least a 4-point reduction in weekly PP-NRS score from baseline to week 12 and the percent change in Dermatology Life Quality Index (DLQI) scores.

Results

A total of 10 patients with PN (mean [SD] age, 58.6 [13.1] years; all were female) and 10 patients with CPUO (mean [SD] age, 70.7 [5.6] years; 2 were female) enrolled in the study. The mean (SD) baseline PP-NRS score was 9.2 (1.0) for PN and 8.2 (1.2) for CPUO. PP-NRS scores decreased by 78.3% in PN (95% CI, -118.5 to -38.1; P < .001) and 53.7% in CPUO (95% CI, -98.8 to -8.6; P = .01) by week 12. From baseline to week 12, 8 of 10 patients with PN and 6 of 10 patients with CPUO achieved at least a 4-point improvement on the PP-NRS. Both groups experienced significant improvement in quality of life as demonstrated by percent change in DLQI scores (PN: -53.2% [95% CI, -75.3% to -31.1%]; P = .002; CPUO: -49.0% [95% CI, -89.6% to -8.0%]; P = .02). The most common adverse event among patients was acneiform eruption in 2 of 20 patients (10%). No serious adverse events occurred.

Conclusions and Relevance

The results of this nonrandomized controlled trial suggest that abrocitinib monotherapy may be effective and tolerated well in adults with PN or CPUO. Randomized, double-blind, placebo-controlled trials are warranted to validate these findings.

Trial Registration

ClinicalTrials.gov Identifier: NCT05038982.

A critical evaluation of nemolizumab for prurigo nodularis

INTRODUCTION

Prurigo nodularis (PN) is a chronic inflammatory skin condition that presents with intensely pruritic, hyperkeratotic nodules. The pathophysiology underlying PN is not entirely clear, making treatment challenging. Patients often require a multimodal approach, although many of the available therapies have low efficacy or adverse effects.

AREAS COVERED

In this review, we discuss the use of nemolizumab for the treatment of PN in adults. Nemolizumab is a biological therapy that reduces type 2 cytokines and the neuroimmune response implicated in the pathophysiology of PN. It also helps maintain skin barrier integrity, which may be damaged during the vicious itch-scratch cycle. Nemolizumab has demonstrated great efficacy in improving itch and clearing lesions in recent clinical trials with respectable tolerance.

EXPERT OPINION

Nemolizumab is a promising drug for PN that seems comparable to the recently approved dupilumab in terms of its therapeutic effect and excellent safety profile, although nemolizumab may work more rapidly on itch. JAK inhibitors are also emerging as competitors of biologics for PN, however, their safety profile in this population may differ. Trials evaluating these drugs are needed to assess which is preferable. Additional data on the durability and longevity of nemolizumab for PN treatment is highly anticipated.

Prurigo nodularis: new insights into pathogenesis and novel therapeutics

Prurigo nodularis (PN) is an inflammatory skin condition characterized by intensely pruritic nodules on the skin. Patients with PN suffer from an intractable itch-scratch cycle leading to impaired sleep, psychosocial distress and a significant disruption in quality of life. The pathogenesis of PN is associated with immune and neural dysregulation, mediated by inflammatory cytokines [such as interleukin (IL)-4, -13, -17, -22 and -31] and neuropeptides (such as substance P and calcitonin gene-related peptide). There is a role for type 2 inflammation in PN in addition to T-helper (Th)17 and Th22-mediated inflammation. The neuroimmune feedback loop in PN involves neuropeptides released from nerve fibres that cause vasodilation and further recruitment of inflammatory cells. Inflammatory cells, particularly mast cells and eosinophils, degranulate and release neurotoxins, as well as nerve growth factor, which may contribute to the neuronal hyperplasia seen in the dermis of patients with PN and neural sensitization. Recent studies have also indicated underlying genetic susceptibility to PN in addition to environmental factors, the existence of various disease endotypes centred around degrees of type 2 inflammation or underlying myelopathy or spinal disc disease, and significant race and ethnicity-based differences, with African Americans having densely fibrotic skin lesions. Dupilumab became the first US Food and Drug Administration-approved therapeutic for PN, and there are several other agents currently in development. The anti-IL-31 receptor A inhibitor nemolizumab is in late-stage development with positive phase III data reported. In addition, the oral Janus kinase (JAK) 1 inhibitors, abrocitinib and povorcitinib, are in phase II trials while a topical JAK1/2 inhibitor, ruxolitinib, is in phase III studies.

Prurigo Nodularis: Pathogenesis and the Horizon of Potential Therapeutics

Chronic pruritus that lasts for over 6 weeks can present in various forms, like papules, nodules, and plaque types, with prurigo nodularis (PN) being the most prevalent. The pathogenesis of PN involves the dysregulation of immune cell-neural circuits and is associated with peripheral neuropathies, possibly due to chronic scratching. PN is a persistent and challenging condition, involving complex interactions among the skin, immune system, and nervous system. Lesional skin in PN exhibits the infiltration of diverse immune cells like T cells, eosinophils, macrophages, and mast cells, leading to the release of inflammatory cytokines and itch-inducing substances. Activated sensory nerve fibers aggravate pruritus by releasing neurotransmitters, perpetuating a vicious cycle of itching and scratching. Traditional treatments often fail, but recent advancements in understanding the inflammatory and itch transmission mechanisms of PN have paved the way for innovative therapeutic approaches, which are explored in this review.

Consensus on the diagnostic algorithm for chronic nodular prurigo

Chronic nodular prurigo (CNP) is a chronic dermatological disease characterized by the presence of chronic pruritus and pruritic nodular lesions. The aim of this study was to reach consensus among a group of experts based on a non-systematic literature review and an algorithm for the clinical diagnosis of CNP. The resulting algorithm is structured in 3 blocks: 1) early identification of the patient with a possible diagnosis of CNP; 2) diagnosis and assessment of CNP; and 3) categorization of CNP (identification of the underlying causes or associated comorbidities). We believe that this clinical algorithm can facilitate the correct diagnosis of patients with CNP. Additionally, it raises awareness on the need for a multidisciplinary approach and specific treatment of CNP, steps of paramount importance to make better therapeutic decisions.

Increased cardiovascular risks and mortality in prurigo nodularis: a global cohort study

BACKGROUND

Prurigo nodularis (PN) presents with intensely itchy hard nodules. Despite being limited to the skin, PN was noted to be associated with systemic diseases including diabetes and chronic renal failure. In previous smaller retrospective studies, several cardiac and vascular diseases were found more frequently in patients with PN. However, small cohort sizes, partially discrepant outcomes, missing data, and incomplete risk assessment limit these findings.

METHODS

Electronic health records (EHR)s of 64,801 patients (59.44% females) with PN and an equal sized propensity-matched control group were retrieved. In these cohorts, the risks to develop cardiac and vascular diseases and mortality following the diagnosis of PN were determined. Sub-analyses included stratification for sex, ethnicity, and treatments.

FINDINGS

PN was associated with a higher risk for a broad range of acute cardiac events including heart failure and myocardial infarction. For example, the hazard ratio of myocardial infarction was 1.11 (95%-CI: 1.041-1.184, p = 0.0015) following PN diagnosis. Also, all-cause mortality was higher in patients with PN. Further, chronic vascular as well as structural heart diseases, e.g., peripheral arterial disease, chronic ischaemic heart disease and valval disorders were found more frequently following a PN diagnosis. Risks were more pronounced in white and female patients. Having established an increased risk for death and cardiovascular disease, we next addressed if dupilumab that has been recently licenced for use in this indication can modulate these risks. The risk of death but not of any cardiovascular disease was slightly reduced in patients with PN treated with dupilumab as opposed to those treated with systemic therapies other than dupilumab. The study is limited by retrospective data collection and reliance on ICD10-disease classification.

INTERPRETATION

PN is associated with higher mortality and an increased risk for the development of a wide range of cardiac and vascular diseases. Health care professionals should take this into account when managing patients with PN.

FUNDING

This work was supported by the University of Lübeck, the Deutsche Forschungsgemeinschaft and the State of Schleswig-Holstein.

Comprehensive plasma cytokine and chemokine profiling in prurigo nodularis reveals endotypes in Type 2 inflammation

Prurigo nodularis (PN) is a chronic inflammatory skin disease that is associated with variability in peripheral blood eosinophil levels and response to T-helper 2 targeted therapies (Th2). Our objective was to determine whether circulating immune profiles with respect to type 2 inflammation differ by race and peripheral blood eosinophil count. Plasma from 56 PN patients and 13 matched healthy controls was assayed for 54 inflammatory biomarkers. We compared biomarker levels between PN and HCs, among PN patients based on absolute eosinophil count, and across racial groups in PN. Eleven biomarkers were elevated in PN versus HCs including interleukin (IL)-12/IL-23p40, tumor necrosis factor-alpha (TNF-α), Thymic stromal lymphopoietin (TSLP), and macrophage-derived chemokine (MDC/CCL22). Additionally, PN patients with AEC > 0.3 K cells/μL had higher Th2 markers (eotaxin, eotaxin-3, TSLP, MCP-4/CCL13), and African American PN patients had lower eosinophils, eotaxin, and eotaxin-3 versus Caucasian and Asian PN patients (p < 0.05 for all). Dupilumab responders had higher AEC (p < 0.01), were more likely to be Caucasian (p = 0.02) or Asian (p = 0.05) compared to African Americans, and more often had a history of atopy (p = 0.08). This study suggests that blood AEC > 0.3 K and Asian and Caucasian races are associated with Th2 skewed circulating immune profiles and response to Th2 targeted therapies.

Neuroimmune interplay during type 2 inflammation: Symptoms, mechanisms, and therapeutic targets in atopic diseases

Type 2 inflammation is characterized by overexpression and heightened activity of type 2 cytokines, mediators, and cells that drive neuroimmune activation and sensitization to previously subthreshold stimuli. The consequences of altered neuroimmune activity differ by tissue type and disease; they include skin inflammation, sensitization to pruritogens, and itch amplification in atopic dermatitis and prurigo nodularis; airway inflammation and/or hyperresponsiveness, loss of expiratory volume, airflow obstruction and increased mucus production in asthma; loss of sense of smell in chronic rhinosinusitis with nasal polyps; and dysphagia in eosinophilic esophagitis. We describe the neuroimmune interactions that underlie the various sensory and autonomic pathologies in type 2 inflammatory diseases and present recent advances in targeted treatment approaches to reduce type 2 inflammation and its associated symptoms in these diseases. Further research is needed to better understand the neuroimmune mechanisms that underlie chronic, sustained inflammation and its related sensory pathologies in diseases associated with type 2 inflammation.

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.

A critical review of dupilumab for adult patients with prurigo nodularis

INTRODUCTION

Prurigo nodularis (PN) is a chronic inflammatory skin condition that presents with pruritus and hyperkeratotic nodules. These symptoms impact patients' quality of life and mental health. Treating prurigo nodularis is challenging, and many of the available topical and systemic therapies have limited efficacy and a myriad of adverse effects.

AREAS COVERED

In this article, we discuss the use of dupilumab for adult patients with prurigo nodularis. Dupilumab is a biologic that inhibits Th2-mediated inflammation and has been successfully used to treat a variety of dermatologic disorders. Dupilumab has revolutionized the management of PN, with recent clinical trials showing its efficacy in treating both pruritus and prurigo nodules, as well as improving quality of life. It has a favorable safety profile and is well tolerated. Other novel treatments are also currently under investigation for the treatment of PN, with early studies reporting promising results.

EXPERT OPINION

Dupilumab is becoming the drug of choice for the treatment of PN and may also be effective in treating patients with systemic underlying causes of their PN, although more studies are needed to assess this. Trials evaluating the long-term efficacy and durability of dupilumab in PN are also of interest.

Clinical Characteristics and Treatment Outcomes of Prurigo Nodularis: A Retrospective Study

BACKGROUND

Prurigo nodularis (PN) is a complex chronic skin disease characterized by severe pruritic nodules. PN is often associated with mental health disorders and chronic medical comorbidities. Until recently, PN treatment has been challenging and difficult.

OBJECTIVES

This study aims to describe the demographic, clinical characteristics, and comorbidities associated with PN. Also, we aim to describe the effectiveness of systemic therapies, including methotrexate, cyclosporine, and narrow band ultraviolet (NB-UVB) in adult patients with PN.

METHODS

This is a retrospective chart review of adult patients diagnosed with PN at Hamilton Health Science Center and/or McMaster University in Hamilton, Ontario, between 2015 and 2023.

RESULTS

The study included 81 patients (57% female). The mean age was 52.8 years, and the mean age of PN diagnosis was 50 years. Reported symptoms included: itching (100%), dry skin (53%), pain (17%), and burning sensation (5%). Lower and upper extremities were the most common areas involved in 93% and 69%, respectively. Mental health disorders were present in 79% of patients, with depression (58%) and anxiety (52%) being the most common. Atopic dermatitis was the most common skin comorbidity noted. Treatments used included cyclosporine, and NB-UVB, and MTX, which resulted in significant improvement of pruritus in 38%, 35%, and 31% of patients, respectively, at week 16.

CONCLUSIONS

PN is associated with increased risk of mental health disorders and other medical comorbidities. Cyclosporine, methotrexate, and NB-UVB therapy may be effective treatment options, however clinicians must consider the potential short- and long-term adverse effects of these treatments.

Disease burden and treatment satisfaction in patients with prurigo nodularis in Japan

Prurigo nodularis (PN) is a chronic inflammatory skin disorder with a high disease burden. In this cross-sectional, web-based survey, Global Questions (GQ), the Numerical Rating Scales (NRS) for pruritus, burning sensation and sleep disturbance, the Short-Form-8 (SF-8) Health Survey, Dermatology Life Quality Index (DLQI), Patient Health Questionnaire 9 (PHQ-9), Work Productivity and Activity Impairment (WPAI), and Treatment Satisfaction Questionnaire for Medication-9 (TSQM-9) scores were used to assess the current disease burden and treatment satisfaction among patients with PN in Japan. In total, 97 patients were included (55.7% male, median age 51 years, median duration of PN 36 months). Based on GQ scores, 35.1% of patients had mild disease, 50.5% moderate, and 14.4% severe disease. Disease burden increased as the severity of PN increased, as indicated by worsening of pruritus NRS scores and quality of life (DLQI, PHQ-9, WPAI presenteeism, work productivity loss, and activity impairment scores). Patients with comorbid atopic dermatitis (AD) also had more intense pruritus than those without AD. Mean ± standard deviation TSQM-9 scores for effectiveness, convenience, and global satisfaction were 54.7 ± 18.1%, 62.4 ± 15.2%, and 57.4 ± 15.9%, respectively. TSQM-9 scores were lowest in patients receiving the most intensive guideline-directed treatment (i.e., topical corticosteroids + systemic oral corticosteroids or cyclosporine), highlighting an unmet need for more effective treatment options for patients with PN. In summary, Japanese patients with PN reported increased disease burden and reduced treatment satisfaction with increased disease severity, despite the use of guideline-recommended therapies.

Characterization of Paediatric Prurigo Nodularis: A Multicentre Retrospective, Observational Study

Abstract is missing (Short communication)

New insight into prurigo nodularis: Proadrenomedullin N-terminal 20 peptide mediates mouse mast cell activation via Mrgprb2

BACKGROUND

Prurigo nodularis (PN) is a chronic inflammatory skin disorder that is characterized by extremely itchy nodules. Proadrenomedullin N-terminal 20 (PAMP) activates mast cell degranulation via Mas-related G protein-coupled receptor X2 (MRGPRX2), which is associated with pruritus in allergic contact dermatitis. However, the mechanisms underlying the action of PAMP and MRGPRX2 in PN remain unclear.

OBJECTIVE

To determine the role of PAMP-induced mast cell activation via MRGPRX2 (mouse homologous Mrgprb2) in PN.

METHODS

The expression of PAMP and the number of MRGPRX2-expressing mast cells in the skin biopsies of patients with PN, atopic dermatitis (AD), and healthy participants were analyzed using immunohistochemistry and immunofluorescence, respectively. The biphasic response of PAMP9-20 mediated by Mrgprb2 in mouse peritoneal mast cells (PMC) was validated in vitro using qRT-PCR, ELISA, flow cytometry, and siRNA techniques.

RESULTS

PAMP expression and the number of MRGPRX2+ mast cells in lesional PN skin, but not in AD, were elevated compared to healthy skin. PAMP9-20 mediates the immediate and delayed phase responses of PMC, such as degranulation, histamine and β-hexosaminidase release, and secretion of inflammatory factors such as CCL2, TNF-α, and GM-CSF. These effects were inhibited when Mrgprb2 expression was silenced. Silencing Mrgprb2 did not affect the biphasic response of PMC that was induced by IgE-FcεRI activation.

CONCLUSIONS

The results show that PAMP mediates mouse mast cell activation via Mrgprb2, which may be involved in the pathogenesis of PN. The PAMP/ Mrgprb2 pathway, independent of classical IgE signaling, could be developed as a candidate drug target for treating PN.

Single-cell profiling of prurigo nodularis demonstrates immune-stromal crosstalk driving profibrotic responses and reversal with nemolizumab

BACKGROUND

Prurigo nodularis (PN) is a chronic neuroimmune skin disease characterized by bilaterally distributed pruritic hyperkeratotic nodules on extremities and trunk. Neuroimmune dysregulation and chronic scratching are believed to both induce and maintain the characteristic lesions.

OBJECTIVES

This study sought to provide a comprehensive view of the molecular pathogenesis of PN at the single-cell level to identify and outline key pathologic processes and the cell types involved. Features that distinguish PN skin from the skin of patients with atopic dermatitis were of particular interest. We further aimed to determine the impact of the IL31RA antagonist, nemolizumab, and its specificity at the single-cell level.

METHODS

Single-cell RNA-sequencing of skin from 15 healthy donors and nonlesional and lesional skin from 6 patients each with PN and atopic dermatitis, combined with spatial-sequencing using the 10x Visium platform. Integration with bulk RNA-sequencing data from patients treated with nemolizumab.

RESULTS

This study demonstrates that PN is an inflammatory skin disease characterized by both keratinocyte proliferation and activation of profibrotic responses. This study also demonstrates that the COL11A1+ fibroblast subset is a major contributor to fibrosis and is predominantly found in the papillary dermis of PN skin. Activation of fibrotic responses is the main distinguishing feature between PN and atopic dermatitis skin. This study further shows the broad effect of nemolizumab on PN cell types, with a prominent effect driving COL11A1+ fibroblast and keratinocyte responses toward normal.

CONCLUSIONS

This study provides a high-resolution characterization of the cell types and cellular processes activated in PN skin, establishing PN as a chronic fibrotic inflammatory skin disease. It further demonstrates the broad effect of nemolizumab on pathological processes in PN skin.

Chronic Prurigo Including Prurigo Nodularis: New Insights and Treatments

Chronic prurigo (CPG) is a neuroinflammatory, fibrotic dermatosis that is defined by the presence of chronic pruritus (itch lasting longer than 6 weeks), scratch-associated pruriginous skin lesions and history of repeated scratching. Patients with CPG experience a significant psychological burden and a notable impairment in their quality of life. Chronic prurigo of nodular type (CNPG; synonym: prurigo nodularis) represents the most common subtype of CPG. As CNPG is representative for all CPG subtypes, we refer in this review to both CNPG and CPG. We provide an overview of the clinical characteristics and assessment of CPG, the burden of disease and the underlying pathophysiology including associated therapeutic targets. The information provided results from a PubMed search for the latest publications and a database search for current clinical trials (ClinicalTrials.gov, EU Clinical Trials Register [European Medicines Agency]; using the following terms or combinations of terms: 'chronic prurigo', 'prurigo', 'prurigo nodularis', 'pathophysiology', 'therapy', 'biologics', 'treatment'). Dupilumab is the first authorized systemic therapy by the European Medicines Agency (EMA) and the US Food and Drug Administration (FDA) for CNPG to date. Topical and systemic agents that are currently under investigation in clinical randomized, placebo-controlled phase II and III trials such as biologics (e.g., nemolizumab, vixarelimab/KPL-716, barzolvolimab/CDX-0159), small molecules (ruxolitinib cream, povorcitinib/INCB054707, abrocitinib) and the opioid modulator nalbuphine are highlighted. In the last past 15 years, several milestones have been reached regarding the disease understanding of CPG such as first transcriptomic analysis, first terminology, first guideline, and first therapy approval in 2022, which contributed to improved medical care of affected patients. The broad range of identified targets, current case observations and initiated trials offers the possibility of more drug approvals in the near future.

Clinical utility of peripheral blood laboratory testing in the diagnostic workup of prurigo nodularis: A multicenter cohort study

Background

Prurigo nodularis (PN) is a chronic inflammatory skin disease associated with several systemic comorbidities. However, there is lack of evidence supporting specific laboratory testing in the diagnostic workup of PN patients.

Objective

To characterize the frequency and severity of clinical laboratory abnormalities in PN patients compared to controls.

Methods

Cross-sectional study of adult patients between October, 2015 and August, 2021 using TriNetX, a global health records database encompassing over 74 million patients.

Results

A total of 12,157 PN patients were matched to 12,157 controls. Significantly, greater proportions of PN patients had moderate-to-severely decreased hemoglobin, elevated transaminases, decreased albumin, increased bilirubin, increased serum creatinine, decreased estimated glomerular filtration rate, higher hemoglobin A1c levels, and alterations in thyroid stimulating hormone.

Limitations

Our data identifies associated laboratory abnormalities in PN patients but is unable to support a causal relationship.

Conclusion

PN patients are more likely to have laboratory abnormalities on renal, hepatic, hematologic, endocrine, and metabolic laboratory testing, demonstrating a role for systemic testing in the diagnostic workup of PN patients.

A Polygenic Risk Score for Predicting Racial and Genetic Susceptibility to Prurigo Nodularis

Prurigo nodularis (PN) is an understudied inflammatory skin disease characterized by pruritic, hyperkeratotic nodules. Identifying the genetic factors underlying PN could help to better understand its etiology and guide the development of therapies. In this study, we developed a polygenic risk score that predicts a diagnosis of PN (OR = 1.41, P = 1.6 × 10-5) in two independent and continentally distinct populations. We also performed GWASs, which uncovered genetic variants associated with PN, including one near PLCB4 (rs6039266: OR = 3.15, P = 4.8 × 10-8) and others near TXNRD1 (rs34217906: OR = 1.71, P = 6.4 × 10-7; rs7134193: OR = 1.57, P = 1.1 × 10-6). Finally, we discovered that Black patients have over a two-times greater genetic risk of developing PN (OR = 2.63, P = 7.8 × 10-4). Combining the polygenic risk score and self-reported race together was significantly predictive of PN (OR = 1.32, P = 4.7 × 10-3). Strikingly, this association was more significant with race than after adjusting for genetic ancestry. Because race is a sociocultural construct and not a genetically bound category, our findings suggest that genetics, environmental influence, and social determinants of health likely affect the development of PN and may contribute to clinically observed racial disparities.

Clinical Characteristics of Lichen Amyloidosis Associated with Atopic Dermatitis: A Single Center, Retrospective Study

BACKGROUND

Lichen amyloidosis is a chronic pruritic skin disorder associated with atopic dermatitis, however, the pathogenetic link between these two conditions remains to be elucidated. Only limited research has been performed on patients diagnosed with both pruritic dermatological conditions.

OBJECTIVE

This study aimed to analyze the clinical features of lichen amyloidosis associated with atopic dermatitis.

METHODS

We conducted a matched case-control study of incident lichen amyloidosis with atopic dermatitis between March 2020 and February 2022. Among the 2,481 patients with atopic dermatitis, 20 patients diagnosed with lichen amyloidosis and atopic dermatitis were included as case patients, and 20 patients diagnosed with atopic dermatitis were enrolled as controls. The controls were matched to cases (1:1) by age and sex. We retrospectively reviewed the medical records of the patients.

RESULTS

The prevalence of lichen amyloidosis associated with atopic dermatitis was approximately 0.8%, with a male:female sex ratio of 2.33:1. The recorded onset of lichen amyloidosis associated with atopic dermatitis was more common in adult patients, with moderate-to-severe atopic dermatitis. Lichen amyloidosis lesions in patients with atopic dermatitis were most commonly found on the extremities, sparing the head and neck region. The presence of lichen amyloidosis had no significant impact on severity of atopic dermatitis.

CONCLUSION

In patients with lichen amyloidosis associated with atopic dermatitis, the clinical manifestations of lesions are similar to those of conventional lichen amyloidosis lesions in terms of morphology and regional distribution. Further research is required to elucidate the link between the pathogenesis of these two pruritic dermatological conditions.

Molecular mechanisms of pruritus in prurigo nodularis

Pruritus is the most common symptom of dermatological disorders, and prurigo nodularis (PN) is notorious for intractable and severe itching. Conventional treatments often yield disappointing outcomes, significantly affecting patients' quality of life and psychological well-being. The pathogenesis of PN is associated with a self-sustained "itch-scratch" vicious cycle. Recent investigations of PN-related itch have partially revealed the intricate interactions within the cutaneous neuroimmune network; however, the underlying mechanism remains undetermined. Itch mediators play a key role in pruritus amplification in PN and understanding their action mechanism will undoubtedly lead to the development of novel targeted antipruritic agents. In this review, we describe a series of pruritogens and receptors involved in mediating itching in PN, including cytokines, neuropeptides, extracellular matrix proteins, vasculogenic substances, ion channels, and intracellular signaling pathways. Moreover, we provide a prospective outlook on potential therapies based on existing findings.

Patient Perspectives on Living With Severe Prurigo Nodularis

Importance

Because of a paucity of qualitative research on prurigo nodularis (PN), the symptoms and impacts of PN that are most important to patients are poorly understood.

Objective

To explore patients' perspectives on their PN symptoms and to understand the impacts of the condition.

Design, Setting, and Participants

One-on-one qualitative telephone interviews were held with English-speaking US adults aged 18 years or older with a confirmed diagnosis of PN, severe pruritus, and moderate to severe sleep disturbance. Participants were recruited via patient associations, patient panels, and social media posts. Interviews took place between September 10, 2020, and March 16, 2021.

Main Outcomes and Measures

The main symptoms of PN and their impacts on quality of life were identified by content analysis of deidentified interview transcripts.

Results

A total of 21 adults with PN (mean [SD] age, 53.1 [11.8] years; 15 [71%] female; 2 African American or Black patients [10%], 1 Asian patient [5%], and 18 White patients [86%]; of these, 1 patient [ 5%] had Hispanic or Latino ethnicity) participated in the interviews. All participants reported itch, pain associated with PN, bleeding or scabbing, and dry skin. Other frequently reported symptoms included lumps or bumps (95%), having a crust on the skin (95%), burning (90%), stinging (90%), lesions or sores (86%), skin discoloration (86%), and raw skin (81%). Of the 17 participants who indicated what their worst symptoms were, 15 (88%) identified itching as the worst or 1 of the worst symptoms. The most frequently reported impacts of PN for quality of life were changes in sleep (100%), daily life (100%), feelings or mood (95%), relationships (95%), social life (81%), and work or school (71%). Overall, the worst impact of PN was its association with impaired feelings or mood.

Conclusions and Relevance

This qualitative study suggests the importance of itching, sleep disturbance, and other symptoms and impacts of PN. This information can be used to guide end point selection in clinical trials and to inform patient-centric decision-making in clinical practice.

Systemic Medication for the Treatment of Prurigo Nodularis-A Systematic Review

IMPORTANCE

Prurigo nodularis (PN) is a debilitating inflammatory skin disease characterized by red to violaceous pruritic lesions. The goal of therapy is to break the scratch-itch cycle. Treatment varies and often requires a multimodal approach to target both immune and neural mediated aspects of disease.

OBJECTIVES

To review the efficacy of systemic treatment used to treat PN.

EVIDENCE REVIEW

A systematic search of keywords and Medical Subject Headings was performed in Ovid MEDLINE, Embase, Scopus, and ClinicalTrials.gov. The first 200 results of an abbreviated search in Google Scholar were also included. PRISMA guidelines were followed and the review was registered on PROSPERO (CRD42023412012). GRADE criteria were used to assess articles for quality of evidence.

FINDINGS

The search resulted in 1153 articles; 382 were duplicates, 643 were irrelevant, 19 were not retrieved, 21 were abstract only, and 88 are included in this review. There were 24 studies on dupilumab, 16 on thalidomide, 8 on cyclosporin, 7 on methotrexate, 3 each on lenalidomide and aprepitant, 2 each on alitretinoin, apremilast, baricitinib, gabapentin, intravenous (IV) immunoglobulins, pregabalin, tofacitinib, and 1 each on amitriptyline, azathioprine, butorphanol, isoquercitin, IV dexamethasone-cyclophosphamide/ oral cyclophosphamide, ketotifen, metronidazole, montelukast, nalbuphine, nemolizumab, serolopitant, tacrolimus, and herose derma zima capsule.

CONCLUSIONS AND RELEVANCE

Dupilumab reduces pruritus and appearance of lesions and is associated with the fewest number of side effects. Thalidomide and pregabalin are also effective, but their long-term use is limited by muscle and nerve pain. Janus Kinase inhibitors may be beneficial, but large population studies are lacking.

Validation of the Peak Pruritus Numerical Rating Scale as a Patient-Reported Outcome Measure in Prurigo Nodularis

INTRODUCTION

Validated patient report tools for quantifying patient experiences of itch in prurigo nodularis (PN) are limited. This study aimed to evaluate the validity of the 11-point peak pruritus numerical rating scale (PP NRS) as a single-item patient-reported outcome (PRO) measure for assessing itch severity in PN.

METHODS

Content validity of the PP NRS was evaluated through qualitative interviews with adults with PN. The PP NRS was then psychometrically evaluated using data from a placebo-controlled trial of nemolizumab in adults with PN, during which patients completed the PP NRS daily. Meaningful within-patient change was estimated from the qualitative interviews and by anchor- and distribution-based analyses of trial data.

RESULTS

The interview participants (N = 21) all understood the PP NRS and reported itch as their worst symptom overall. The PP NRS showed good test-retest reliability and demonstrated convergent validity and known-groups validity. PP NRS scores improved more in patients classified as "improved" on other clinical outcome measures than in those classified as "worsened/unchanged". Triangulation of the different estimates identified a 2- to 5-point decrease in PP NRS score as a meaningful within-patient change threshold.

CONCLUSION

The PP NRS is a content-valid and reliable PRO measure for quantifying itch severity in adults with PN in clinical trials.

TRIAL REGISTRATION NUMBER

NCT03181503.

New insight into the role of fibroblasts in the epithelial immune microenvironment in the single-cell era

The skin is exposed to environmental challenges and contains heterogeneous cell populations such as epithelial cells, stromal cells, and skin-resident immune cells. As the most abundant type of stromal cells, fibroblasts have been historically considered silent observers in the immune responses of the cutaneous epithelial immune microenvironment (EIME), with little research conducted on their heterogeneity and immune-related functions. Single-cell RNA sequencing (scRNA-seq) and spatial transcriptomics (ST) have overcome the limitations of bulk RNA sequencing and help recognize the functional and spatial heterogeneity of fibroblasts, as well as their crosstalk with other types of cells in the cutaneous EIME. Recently, emerging single-cell sequencing data have demonstrated that fibroblasts notably participate in the immune responses of the EIME and impact the initiation and progression of inflammatory skin diseases. Here, we summarize the latest advances in the role of fibroblasts in the cutaneous EIME of inflammatory skin diseases and discuss the distinct functions and molecular mechanisms of activated fibroblasts in fibrotic skin diseases and non-fibrotic inflammatory skin diseases. This review help unveil the multiple roles of fibroblasts in the cutaneous EIME and offer new promising therapeutic strategies for the management of inflammatory skin diseases by targeting fibroblasts or the fibroblast-centered EIME.

Modulation of Neuroimmune and Epithelial Dysregulation in Patients With Moderate to Severe Prurigo Nodularis Treated With Nemolizumab

Importance

Prurigo nodularis (PN) is a debilitating skin disease characterized by intense pruritus and hyperkeratotic skin nodules. Nemolizumab, a monoclonal antibody targeting interleukin 31 receptor α, is a promising novel therapy for the treatment of moderate to severe PN. The biological mechanisms by which nemolizumab promotes improvement of itch and skin lesions in PN are unknown.

Objective

To characterize changes in plasma protein biomarkers associated with clinical response to nemolizumab in patients with PN.

Design, Setting, and Participants

This multicenter cohort study included patients recruited from Austria, France, Germany, Poland, and the US from a phase 2 clinical trial. Adults diagnosed with moderate to severe PN with severe pruritus for at least 6 months were included in the original trial. Patients in the nemolizumab group were included in the present study if they achieved at least a 4-point decrease in the Peak Pruritus Numerical Rating Scale (PP-NRS) from baseline to week 12 during nemolizumab treatment. Placebo controls did not experience a 4-point decrease in PP-NRS. Mass spectrometry with tandem mass tags to enrich skin-specific protein detection was used to characterize changes in plasma protein expression in nemolizumab and placebo groups. Data were collected from November 2, 2017, to September 26, 2018, and analyzed from December 6, 2019, to April 8, 2022.

Intervention

As part of the clinical trial, patients were treated with 3 doses of nemolizumab or placebo at 0, 4, and 8 weeks.

Main Outcomes and Measures

Changes in plasma and epidermal protein expression in nemolizumab-treated patients compared with the placebo group at 0, 4, and 12 weeks.

Results

Among the 38 patients included in the analysis (22 women and 16 men; mean [SD] age, 55.8 [15.8] years), enrichment analysis of canonical pathways, biological functions, and upstream regulators showed downregulation of terms involving inflammation (IL-6, acute-phase response, signal transducer and activator of transcription 3, and interferon γ), neural processes (synaptogenesis signaling and neuritogenesis), tissue remodeling and fibrosis (transforming growth factor β1 and endothelin-1), and epidermal differentiation (epithelial mesenchymal transition) in the plasma of nemolizumab group.

Conclusions and Relevance

In this cohort study, differences between nemolizumab and placebo groups included modulation of inflammatory signaling, neural development, and epithelial differentiation, suggesting a promising potential approach for clinical management of PN.

Single-cell RNA sequencing defines disease-specific differences between chronic nodular prurigo and atopic dermatitis

BACKGROUND

Chronic nodular prurigo (CNPG) is an inflammatory skin disease that is maintained by a chronic itch-scratch cycle likely rooted in neuroimmunological dysregulation. This condition may be associated with atopy in some patients, and there are now promising therapeutic results from blocking type 2 cytokines such as IL-4, IL-13, and IL-31.

OBJECTIVES

This study aimed to improve the understanding of pathomechanisms underlying CNPG as well as molecular relationships between CNPG and atopic dermatitis (AD).

METHODS

We profiled skin lesions from patients with CNPG in comparison with AD and healthy control individuals using single-cell RNA sequencing combined with T-cell receptor sequencing.

RESULTS

We found type 2 immune skewing in both CNPG and AD, as evidenced by CD4+ helper T cells expressing IL13. However, only AD harbored an additional, oligoclonally expanded CD8A+IL9R+IL13+ cytotoxic T-cell population, and immune activation pathways were highly upregulated in AD, but less so in CNPG. Conversely, CNPG showed signatures of extracellular matrix organization, collagen synthesis, and fibrosis, including a unique population of CXCL14-IL24+ secretory papillary fibroblasts. Besides known itch mediators such as IL31 and oncostatin M, we also detected increased levels of neuromedin B in fibroblasts of CNPG lesions compared with AD and HC, with neuromedin B receptors detectable on some nerve endings.

CONCLUSIONS

These data show that CNPG does not harbor the strong disease-specific immune activation pathways that are typically found in AD but is rather characterized by upregulated stromal remodeling mechanisms that might have a direct impact on itch fibers.

Cutaneous Squamous Cell Carcinoma Mimickers: Beware the Pruritic Papule on the Leg of an Older Female

Background Correctly identifying cutaneous squamous cell carcinoma (cSCC) mimickers can be both clinically and histopathologically challenging. We present a series of patients with biopsy-proven cSCCs for whom multiple surgeries were avoided by assessing the clinical situation, recognizing an alternative diagnosis that pathologically mimics cSCC, and prescribing appropriate therapy for the underlying condition. Methodology Seven female patients presented for treatment of biopsy-proven cSCC affecting the lower leg. After further investigation, we observed that these women shared similar characteristics, including age ranging from the 5th to the 9th decade, often experiencing stress, exhibiting associated pruritus with diverse causes, having few or no previous skin cancers, and generally showing minimal photodamage. Results In all cases, surgery was deferred and patients demonstrated complete clinical response to therapies directed toward an alternative diagnosis. Repeat biopsies of treated lesions revealed no evidence of cSCC. Conclusions Not all histologically diagnosed cases of cSCC should be treated with surgery, and each patient should be worked up thoroughly to evaluate for an alternative diagnosis. Possible clinical and histologic cSCC mimickers include allergic contact dermatitis (ACD), stasis dermatitis, hypertrophic lichen planus (LP), and drug eruption, among others. In the described population, pruritic papules on the lower leg should prompt further investigation to prevent the morbidity associated with unnecessary surgery.

Pretibial Pruritic Papular Dermatitis: A Case Report and Emphasis on Effective Treatment with Pentoxifylline

Pretibial pruritic papular dermatitis (PPPD) is a distinctive skin disorder in response to persistent pretibial manipulation. Clinically, it manifests as multiple discrete, pruritic, flesh-colored-to-erythematous papules and plaques confined to the pretibial area. The histological hallmark of PPPD comprises irregular epidermal psoriasiform hyperplasia with parakeratosis and spongiosis, dermal fibrosis, and lymphohistiocytic infiltration. Due to its rarity and underrecognition, the prevalence and standard treatment of the disease have yet to be well elucidated. Here, we present a case of PPPD in a 60-year-old female presenting with numerous pruritic, erythematous-to-brownish papules and plaques on bilateral pretibial areas for 1.5 years. The lesions were significantly improved after 1 month of additional treatment with oral pentoxifylline. In this report, we aim to raise awareness in recognizing PPPD since it manifests unique clinical, dermoscopic, and histological features, representing pretibial skin's response to chronic rubbing. In addition, we proposed a novel effective therapy for the disease using pentoxifylline.

The Sleep Disturbance Numerical Rating Scale: Content Validity, Psychometric Validation, and Meaningful Within-Patient Change in Prurigo Nodularis

INTRODUCTION

Sleep is often disturbed in patients with prurigo nodularis (PN). To address the lack of validated patient-reported outcome (PRO) measures for quantifying sleep disturbance in PN, we evaluated the Sleep Disturbance Numerical Rating Scale (SD NRS) as a single-item PRO measure for quantifying sleep disturbance in PN.

METHODS

Adults with PN participated in qualitative interviews, which included concept elicitation and cognitive debriefing of the SD NRS. The SD NRS was evaluated psychometrically using data from a phase 2 randomized trial in adults with PN (NCT03181503). Other PRO assessments included the Average Pruritus (AP) NRS, AP Verbal Rating Scale (VRS), peak pruritus (PP) NRS, PP VRS, and Dermatology Life Quality Index (DLQI). Reliability, validity, and responsiveness of the SD NRS were evaluated, and meaningful within-patient change was estimated from qualitative interview responses and quantitative trial data.

RESULTS

All interview participants (N = 21) experienced sleep disturbance and most (95%) understood the SD NRS as intended. The SD NRS demonstrated test-retest reliability based on intra-class correlation coefficients for itch-stable participants of 0.87 for the AP VRS and 0.76 for the PP VRS. At baseline, Spearman's rank-order correlation coefficients were moderate to strong (0.3-0.8) between the SD NRS and the AP NRS, AP VRS, PP NRS, PP VRS, and DLQI. Known-groups validity was demonstrated by higher (worse) SD NRS scores in participants with worse scores on the AP NRS, AP VRS, PP VRS, and DLQI. Improvements in SD NRS scores were greater in participants classified as "improved" versus "worsened/unchanged" on the anchor PROs. A 2- to 4-point decrease on the 11-point SD NRS scale was identified as a meaningful within-patient change.

CONCLUSION

The SD NRS is a well-defined, reliable, and valid PRO measure that can be used in daily practice and clinical trials to capture sleep disturbance in adults with PN.

Case Report: Prurigo nodularis-like linear IgA/IgG bullous dermatosis: a case report and literature review

Linear IgA/IgG bullous dermatosis (LAGBD) is a rare autoimmune subepidermal bullous disorder characterized by linear deposition of concurrent IgA and IgG autoantibodies along the basement membrane zone (BMZ). The clinical features of LAGBD can be diverse, including tense blisters, erosions, erythema, crusting and mucosa involvement, while papules or nodules are generally absent. In this study, we present a unique case of LAGBD, which showed prurigo nodularis-like clinical appearance on physical examination, linear deposition of IgG and C3 along the basement membrane zone (BMZ) in direct immunofluorescence (DIF), IgA autoantibodies against the 97-kDa and 120-kDa of BP180 and IgG autoantibodies against the 97-kDa of BP180 by immunoblotting (IB), while BP180 NC16a domain, BP230, and laminin 332 were negative by enzyme-linked immunosorbent assay (ELISA). After administration of minocycline, the skin lesions improved. We performed a literature review of LAGBD cases with heterogeneous autoantibodies and found clinical presentations of most cases resemble bullous pemphigoid (BP) and linear IgA bullous disease (LABD), which is consistent with previous reported findings. We aim to increase our understanding of this disorder and to enhance the importance of applying immunoblot analyses and other serological detection tools in clinic for precise diagnosis as well as accurate treatment strategy of various autoimmune bullous dermatoses.

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 .

The blood proteomic signature of prurigo nodularis reveals distinct inflammatory and neuropathic endotypes: A cluster analysis

BACKGROUND

Prurigo nodularis (PN) is an extremely pruritic, chronic inflammatory skin disease. Little is known about systemic inflammation in PN.

OBJECTIVE

To characterize plasma inflammatory biomarkers in patients with PN and investigate the presence of disease endotypes.

METHODS

In this cross-sectional study, Olink proteomic analysis was performed on plasma samples from patients with PN (n = 29) and healthy controls (n = 18).

RESULTS

Patients with PN had increased levels of 8 circulating biomarkers compared to controls, including tumor necrosis factor, C-X-C Motif Chemokine Ligand 9, interleukin-12B, and tumor necrosis factor receptor superfamily member 9 (P < .05). Two PN clusters were identified in cluster 1 (n = 13) and cluster 2 (n = 16). Cluster 2 had higher levels of 25 inflammatory markers than cluster 1. Cluster 1 had a greater percentage of patients with a history of myelopathy and spinal disc disease compared with cluster 2 (69% vs 25%, P = .03). Patients in cluster 2 were more likely to have a history of atopy (38% in cluster 2 vs 8% in cluster 1, P = .09).

LIMITATIONS

Small sample size precludes robust subgroup analyses.

CONCLUSION

This study provides evidence of neuroimmune-biased endotypes in PN and can aid clinicians in managing patients with PN that are nonresponsive to traditional therapies.

Skin Microbiome in Prurigo Nodularis

Prurigo nodularis (PN) is a chronic condition characterized by the presence of nodular lesions accompanied by intense pruritus. The disease has been linked to several infectious factors, but data on the direct presence of microorganisms in the lesions of PN are scarce. The aim of this study was to evaluate the diversity and composition of the bacterial microbiome in PN lesions by targeting the region V3-V4 of 16S rRNA. Skin swabs were obtained from active nodules in 24 patients with PN, inflammatory patches of 14 patients with atopic dermatitis (AD) and corresponding skin areas of 9 healthy volunteers (HV). After DNA extraction, the V3-V4 region of the bacterial 16S rRNA gene was amplified. Sequencing was performed using the Illumina platform on the MiSeq instrument. Operational taxonomic units (OTU) were identified. The identification of taxa was carried out using the Silva v.138 database. There was no statistically significant difference in the alpha-diversity (intra-sample diversity) between the PN, AD and HV groups. The beta-diversity (inter-sample diversity) showed statistically significant differences between the three groups on a global level and in paired analyses. Staphylococcus was significantly more abundant in samples from PN and AD patients than in controls. The difference was maintained across all taxonomic levels. The PN microbiome is highly similar to that of AD. It remains unclear whether the disturbed composition of the microbiome and the domination of Staphylococcus in PN lesions may be the trigger factor of pruritus and lead to the development of cutaneous changes or is a secondary phenomenon. Our preliminary results support the theory that the composition of the skin microbiome in PN is altered and justify further research on the role of the microbiome in this debilitating condition.

Dupilumab Therapy of Prurigo Nodularis: A Single-Center, Real-Life Observational Study

Prurigo nodularis (PN) is a chronic inflammatory skin disease characterized by severe itching accompanied by multiple nodules throughout the body. There is currently no effective drug-targeted treatment for PN. Dupilumab is a fully human monoclonal antibody which can suppress the Th2 inflammatory reaction. We aimed to assess the efficacy and safety of dupilumab in PN. There were 29 PN patients who received dupilumab treatment for four months. Serum total immunoglobulin E (Ig E), eosinophil counts, dermatology life quality index (DLQI), and numeric rating scale (NRS) were assessed on patients before and after treatment. We count the vaccination of novel coronavirus pneumonia (COVID-19) in patients and the impact on PN and treatment measures after vaccination. Plotting was performed using GraphPad Prism8, and the statistical analysis was performed using PASW Statistics18. The eosinophil counts in patients higher decreased to normal, and the Ig E levels gradually decreased and tended to normal levels after receiving dupilumab injection. The average DLQI score at the baseline was 23.93 ± 0.66 and decreased to 11.66 ± 0.55 ( $P<0.01$ ) and 1.83 ± 0.22 ( $P<0.01$ ) at 1-month and 6-monthfollow-up of treatment, respectively. The average NRS score at the baseline was 9.79 ± 0.08 and decreased to 3.52 ± 0.23 ( $P<0.01$ ) and 0.31 ± 0.15 ( $P<0.01$ ) at the 1-month and 6-monthfollow-up of treatment, respectively. Our study shows that dupilumab has achieved good efficacy in PN with few adverse reactions and high safety. We can recommend that patients follow the advice of specialists to be vaccinated and under the condition of stable disease, separated from dupilumab treatment for one week.

A real-world observational study of dupilumab treatment in adult patients with prurigo nodularis

BACKGROUND

Prurigo nodularis (PN) is a chronic inflammatory skin condition that has a significant unmet needs for effective treatment options.

OBJECTIVE

To assess the efficacy and safety of dupilumab in adult patients with PN refractory to traditional therapies.

METHODS

This ongoing, real-life study examined dupilumab treatment in 8 adult patients diagnosed with PN for at least 6 months. The included patients were prescribed 300 mg dupilumab biweekly for at least 16 weeks. Efficacy was the primary outcome by means of multiple standardized scale measurements while safety was also reported.

RESULTS

PN patients treated with dupilumab showed notable clinical improvement. After 16 weeks of dupilumab treatment, the mean Investigator Global Assessment (IGA) score reduced from 3.75 to 1.50. Patients mean Numerical Rating Scale Itch Intensity (NRSI), Dermatology Life Quality Index (DLQI), and Hospital Anxiety and Depression Scale (HADS) ratings reduced from 8.625, 15.13, and 14.50 to 1.563, 4.625, and 1.000 respectively. The majority of the patients (87.5%) reported dupilumab as effective while no adverse events have been reported.

STUDY LIMITATIONS

This study was limited to a small cohort of adult PN patients and a short-time observation period.

CONCLUSIONS

Dupilumab is effective and tolerable in adult PN patients with significant improvement in skin lesions, itching, and quality of life.

Serum Interleukin-13 and Caspase 8 are Elevated in Prurigo Nodularis

Abstract is missing (Short communication)

Generalized prurigo nodularis with dramatic response to dupilumab treatment: A case report

BACKGROUND

Prurigo nodularis (PN) is a chronic condition characterized by a papulonodular pruriginous eruption of unknown aetiology. Currently, there are no medications for PN that the United States Food and Drug Administration has approved, which leads to very variable practices in the prescription of off-label treatments. Treatment of PN is based on clinical experience rather than controlled trials. We present our case of generalized PN, in which we had a dramatic response with dupilumab.

CASE SUMMARY

A 58-year-old female patient was admitted to our clinic with severe itchy, erythematous nodular lesions that were widespread all over her body, especially on the legs and back. It was learned that the patient's complaints started 4 years ago, and there was a significant increase in the lesions in the last period. Dermatological examination revealed diffuse firm erythematous excoriated nodular lesions all over the body. In the blood tests of the patient, serum Immunoglobulin E (IgE) was measured at 9330 IU/mL. The patient was diagnosed with generalized prurigo nodularis together with clinical and histopathological findings. Due to severe clinical findings and the presence of comorbidities, dupilumab treatment was planned for the patient. In the follow-up 4 mo later, it was observed that all nodular lesions healed with postinflammatory hypopigmentation. The IgE value decreased to 1500 IU/mL after 4 mo of dupilumab treatment.

CONCLUSION

Dupilumab treatment stands out as an effective and safe systemic treatment agent among existing systemic treatments.

Recent Advances of Basophils in Pruritic Skin Diseases

Basophils are a rare type of granulocyte in peripheral blood. Owing to their accessibility in circulation and similarities to mast cells, basophils were considered a tool to gain insight into the function of mast cells. However, recent studies have uncovered that basophils have unique biology, specifically in activation, recruitment, and potential biomarkers. Accordingly, some previously unrecognized functions, particularly in neuroimmunology, have been found, suggesting a role of basophils in inflammatory and pruritic disorders. In this review, we aim to present an overview of basophil biology to show how basophils contribute to certain pruritic skin diseases.

Dupilumab for the treatment of prurigo nodularis: A systematic review

Background

Conventional treatment techniques have limited efficacy and more side effects in the treatment of prurigo nodularis. The better alternative treatment option for better outcomes of the disease is dupilumab.

Objective

The objective of this study was to systematically review dupilumab-related treatment outcomes in prurigo nodularis.

Methods

Several databases like Embase, PubMed, Web of Science, and Cochrane library were searched for data acquisition on October 8, 2022. Based on Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines, 24 publications were included in this study.

Results

After 4,12,16 and more than 16 weeks of dupilumab treatment, 8.3% (n=5/60), 34.4% (n=11/32), 3.6% (n=2/56), and 45.3% (n=29/64) of patients had complete remission, respectively. In addition, 85.0% (n=51/60), 59.4% (n=19/32), 83.9% (n=47/56), and 43.8% (n=28/64) had partial remission, respectively. Moreover, 6.7% (n=4/60), 6.3% (n=2/32), 12.5% (n=7/56), and 10.9% (n=7/64) showed no remission, respectively, and significant reduction of numeric rating scale itch intensity (from 9.0 to 4.9, 2.1, 2.8, 0.9) was attained. There were no serious adverse events observed during treatment, but the most common event observed was conjunctivitis (12.6%, n=15/119).

Conclusions

Dupilumab has definite effectiveness and safety in prurigo nodularis treatment.

Systematic review registration

https://www.crd.york.ac.uk/PROSPERO, identifier (CRD42022365802).

RNA sequencing reveals the transcriptome profile of the atopic prurigo nodularis with severe itching

Prurigo nodularis (PN), characterized by inevitable chronicity and severe pruritus, is most frequently associated with atopy compared with other origins. However, the skin transcriptomic profiling of PN arising from atopic dermatitis (AD), so-called atopic PN (APN), remains unclear. We sought to explore the cutaneous transcriptome of APN with severe pruritus and compare it with classic AD. RNA sequencing was performed on the lesional skin from 13 APN to 11 AD patients with severe pruritus (itch numerical rating scale score ≥ 7) and normal skin from 11 healthy subjects. Quantitative real-time polymerase chain reaction and immunochemistry were used for validation. We detected 1085 and 1984 differentially expressed genes (DEGs) in lesional APN skin and lesional AD skin versus normal skin, respectively. In total, 142 itch/inflammation-related DEGs were identified. Itch/inflammation-related DEGs, such as IL-6, IL-10, IL-13, oncostatin M, and IL-4 receptor, had elevated gene transcript levels in both diseases. The itch/inflammation-related DEGs that increased only in APN were mainly neuroactive molecules, while many inflammatory mediators such as T helper 22-related genes were found to be increased only in AD. Both disorders showed mixed Th1/Th2/Th17 polarisation and impaired skin barrier. In contrast to AD, M1/M2 macrophage activation, tumor necrosis factor production, fibrosis, revascularization and neural dysregulation are unique features of APN. The study findings broaden our understanding of the pathogenesis underlying APN, which provides insights into novel pathogenesis with potential therapeutic implications.