Real-World Prevalence of Prurigo Nodularis and Burden of Associated Diseases

Association between atopic dermatitis and prurigo nodularis: a systematic review and meta-analysis

Atopic dermatitis (AD) and prurigo nodularis (PN) are chronic dermatological conditions marked by severe itching and the presence of eczematous lesions such as papules and nodules. Both diseases can pose significant physical and psychological harm, leading to poor quality of life. Notably, AD and PN were clinically linked in the past, with suggestions by researchers that PN might be a distinct clinical phenotype of AD. However, the extent of their relationship had not been fully quantified until our recent investigations. Through a meticulous systematic review and meta-analysis adhering to the PRISMA guidelines, we extensively searched databases, including PubMed, EMBASE, Scopus, and the Cochrane Library, up to February 18, 2024. Our random effects meta-analysis presented a strikingly increased risk of AD in patients suffering from PN as opposed to control groups (pooled unadjusted odds ratio [OR], 16.85; 95% confidence interval [CI], 6.13-46.31; I2 = 100%). Correspondingly, an elevated prevalence of PN was identified in subjects with AD (2.00%; 95% CI, 1.62-2.37%). These findings underscore the close association between AD and PN, suggesting a multifaceted overlap and potential bi-directionality in developing these skin conditions. However, further comprehensive studies are essential to validate these associations and understand their precise clinical implications, with the ultimate goal of refining patient management strategies.

Prevalence, incidence and treatment patterns of prurigo nodularis in England: a retrospective database analysis

BACKGROUND

Prurigo nodularis (PN) is a pruritic skin disease characterized by multiple intensely itchy skin nodules in symmetrically distributed areas of the extremities. There are limited studies on the epidemiology and treatment pathways of PN, especially moderate-to-severe PN, from England.

OBJECTIVES

To assess the epidemiology and treatment pathways of mild and moderate-to-severe PN in England.

METHODS

This retrospective cohort study used data from the Clinical Practice Research Datalink and Hospital Episode Statistics in England. Adult patients (aged ≥ 18 years) with a PN-specific diagnosis code allocated any time between 1 April 2007 and 1 March 2019 (patient identification period) were selected. Patients were included if their first PN diagnostic code (index diagnosis date; IDD) was recorded during the identification period, with data available 6 months before and ≥ 12 months after the IDD. Patients were classified as having moderate-to-severe PN (MSPN) or mild PN (MiPN), based on the presence or absence of a prescription record, post-IDD, for either a systemic immunosuppressant or a gabapentinoid. Patients with MSPN and MiPN were matched 1 : 1 according to age, sex and IDD. Prevalence and incidence were calculated for each year from 2007 to 2019. Drugs prescribed post-IDD were analysed.

RESULTS

A total of 8933 patients (MSPN, n = 2498; MiPN, n = 6435) were included in the study; 2462 patients with MiPN and 2462 with MSPN were included for the comparative analysis. The presence of atopic dermatitis, asthma and eosinophilic oesophagitis were significantly higher (all P < 0.001) in patients with MSPN compared with those with MiPN. The overall prevalence of cases of PN increased during the study period. The incidence rate also showed a similar trend. The rates of prescription of potent and super-potent topical corticosteroids (TCS), topical calcineurin inhibitors, first- and second-generation antihistamines, oral and injectable systemic corticosteroids, methotrexate, antidepressants and tacrolimus were significantly higher (all P < 0.001) in patients with MSPN compared with those with MiPN.

CONCLUSIONS

The epidemiology of PN was consistent with that found in other European studies. Patients with MSPN received a significantly higher number of prescriptions for potent TCS and systemic drugs compared with patients with MiPN.

Current clinical practice of prurigo nodularis in Japan: A cross-sectional web-survey among dermatologists

Prurigo nodularis (PN) is a chronic inflammatory skin disease associated with intense pruritic nodules. The unclear patho-etiological mechanisms of PN cause difficulty in disease management; and there is a paucity of information on the current diagnosis and treatment options for PN in Japan. To describe the current management from a dermatologists' perspective we conducted a web-based survey (UMIN Clinical Trial Registry UMIN000047643) in 2022 among dermatologists from a Japanese commercially available physician panel, who had seen at least one patient with PN within the last 3 months. The survey included 117 dermatologists. The dermatologists diagnosed PN mainly by confirming clinical signs and patient interviews, while to assess the severity of PN, the number of pruritic nodules and the degree of itching were primarily utilized. Topical corticosteroids and antihistamines were the most used drugs, as recommended in the current guidelines on the diagnosis and treatment of prurigo. Dermatologists' treatment satisfaction decreased with increasing assumed severity of PN; almost 65% dermatologists were not satisfied with the treatment of severe PN. These results suggest the need of more effective medications and diagnostic tools for better management of PN in Japan.

Prurigo: review of its pathogenesis, diagnosis, and treatment

Prurigo is a reactive, hyperplastic skin condition characterized by pruritic papules, plaques, and/or nodules. The temporal classification includes acute/subacute and chronic disease (≥ 6 weeks), with different clinical variants, synonymies, and underlying etiological factors. The immunology of chronic prurigo shows similarities with atopic dermatitis due to the involvement of IL-4 and IL-13, IL-22, and IL-31. Treatment includes antihistamines, topical steroids, dupilumab, and JAK inhibitors. Several conditions manifest clinically as prurigo-like lesions, and the correct clinical diagnosis must precede correct treatment. Furthermore, chronic prurigos represent a recalcitrant and distressing dermatosis, and at least 50% of these patients have atopic diathesis, the treatment of which may induce adverse effects, especially in the elderly. The quality of life is significantly compromised, and topical treatments are often unable to control symptoms and skin lesions. Systemic immunosuppressants, immunobiologicals, and JAK inhibitors, despite the cost and potential adverse effects, may be necessary to achieve clinical improvement and quality of life. This manuscript reviews the main types of prurigo, associated diseases, their immunological bases, diagnosis, and treatment.

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.

Abrocitinib Monotherapy for Refractory Prurigo Nodularis: Report of Two Successful Cases

Prurigo nodularis (PN) is a debilitating chronic neuroimmunologic skin condition due to the intense pruritus and difficult to treat. The pruritogenic cytokines, particularly IL-4, IL-13, IL-22, IL-31, and oncostatin M (OSM), play a crucial role in the pathogenesis of PN, potentially involving the JAK1-STAT pathway. An oral JAK1 inhibitor, abrocitinib, is presently undergoing Phase 2 trials for the treatment of PN. We evaluated the efficacy of abrocitinib at a daily dosage of 100 mg in treating two patients with PN affecting both lower limbs: a 50-year-old male with a 16-year disease history and a 38-year-old female with over three years of disease history, both of whom had failed to respond to multiple conventional treatments. Both patients responded rapidly after one week of treatment and exhibited a marked improvement. Following eight weeks of therapy, near-complete resolution of both pruritus and lesions was achieved, and no adverse effects were reported. Additionally, there were no reported side effects during the initial four months of continued treatment. Abrocitinib is an effective targeted therapy for PN, offering a promising new option for refractory patients.

[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.

Efficacy and safety of nemolizumab and topical corticosteroids for prurigo nodularis: results from a randomized double-blind placebo-controlled phase II/III clinical study in patients aged ≥ 13 years

BACKGROUND

Prurigo nodularis (PN), a chronic inflammatory skin condition, adversely affects the quality of life of affected individuals. Current treatment options for PN in Japan are limited.

OBJECTIVES

To evaluate the optimal dose, efficacy and safety of long-term treatment with nemolizumab in patients with PN in Japan.

METHODS

In a 16-week double-blind phase II/III study, patients aged ≥ 13 years with PN were randomly assigned (1 : 1 : 1) to nemolizumab 30-mg, 60-mg or placebo groups, with concomitant topical corticosteroids, every 4 weeks. The primary efficacy endpoint was the percentage change in the weekly mean Peak Pruritus Numerical Rating Scale (PP-NRS) score (range 0-10, with higher scores indicating worse itching) from baseline to week 16. Secondary efficacy endpoints assessed the impact of treatment on pruritus, PN severity, sleep and quality of life.

RESULTS

At week 16, the least-squares mean percentage change from baseline in the PP-NRS score was -61.1% in the nemolizumab 30-mg group (n = 77), -56.0% in the 60-mg group (n = 76), and -18.6% in the placebo group (n = 76). Differences between both nemolizumab groups and placebo were significant; the difference between the 30-mg and placebo groups was -42.5% [95% confidence interval (CI) -51.9 to -33.1; P < 0.0001], and between the 60-mg and placebo groups was -37.4% (95% CI -46.7 to -28.1; P < 0.0001). Patients treated with nemolizumab also had greater improvements in the number and severity of prurigo nodules, and in sleep and quality of life compared with the placebo group. Both nemolizumab doses were well tolerated.

CONCLUSIONS

Improvements in PN were greater following nemolizumab treatment, despite continuation of topical corticosteroids in both groups.

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.

Single-Cell RNA Sequencing Reveals Dysregulated POSTN+WNT5A+ Fibroblast Subclusters in Prurigo Nodularis

Prurigo nodularis (PN) is an intensely pruritic, inflammatory skin disease with a poorly understood pathogenesis. We performed single-cell transcriptomic profiling of 28,695 lesional and nonlesional PN cells. Lesional PN has increased dysregulated fibroblasts (FBs) and myofibroblasts. FBs in lesional PN were shifted toward a cancer-associated FB-like phenotype, with POSTN+WNT5A+ cancer-associated FBs increased in PN and similarly so in squamous cell carcinoma. A multicenter cohort study revealed an increased risk of squamous cell carcinoma and cancer-associated FB-associated malignancies (breast and colorectal) in patients with PN. Systemic fibroproliferative diseases (renal sclerosis and idiopathic pulmonary fibrosis) were upregulated in patients with PN. Ligand-receptor analyses demonstrated an FB neuronal axis with FB-derived WNT5A and periostin interactions with neuronal receptors melanoma cell adhesion molecule and ITGAV. These findings identify a pathogenic and targetable POSTN+WNT5A+ FB subpopulation that may predispose cancer-associated FB-associated malignancies in patients with PN.

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: 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.

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.

A randomized, double-blinded, vehicle-controlled clinical trial of topical cryosim-1, a synthetic TRPM8 agonist, in prurigo nodularis

BACKGROUND

Prurigo nodularis (PN) is an intensively pruritic skin disease that negatively influences quality of life. Cryosim-1 (Intrinsic IB Spot) is a synthetic, selective transient receptor potential melastatin 8 agonist.

AIMS

To investigate the efficacy and safety of cryosim-1 in PN patients.

PATIENTS/METHODS

A randomized, double-blinded, placebo-controlled clinical trial including 30 patients was conducted. The numerical rating scale (NRS) of pruritus was evaluated before and 2 h after cryosim-1 application at every visit.

RESULTS

At week 8, the mean pruritus NRS before serum application (4.7 ± 0.4 treatment, 6.1 ± 0.5 placebo; p = 0.045) and 2 h after serum application (2.8 ± 0.4 treatment, 4.3 ± 0.5 placebo; p = 0.031) were significantly lower in the treatment group, and the mean NRS for sleep disorder was significantly lower in the treatment group (2.2 ± 0.5 treatment, 4.2 ± 0.8 placebo; p = 0.031). The mean satisfaction scales for pruritus improvement were significantly higher in the treatment group (7.2 ± 0.6) than in the placebo group (4.0 ± 0.9; p = 0.005). There was no difference in TEWL between the two groups, and no adverse reactions were reported.

CONCLUSIONS

Cryosim-1 is a safe and effective topical treatment for PN patients.

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.

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.

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.

Risk of incident sleep disorders in patients with prurigo nodularis: A population-level analysis using The Health Improvement Network

Background

Prurigo nodularis (PN) is a chronic inflammatory skin condition characterized by severely itchy and often painful bumps on the arms, legs, and trunk. It is unknown whether patients with PN have increased risk of developing sleep disorders.

Objective

To evaluate the association of PN with sleep disorders.

Methods

This retrospective, population-level, matched-cohort study was conducted using The Health Improvement Network. The study included 4193 patients with newly diagnosed PN and 4193 age, sex, and race/ethnicity-matched controls. A Cox regression model was used to assess the development of sleep disorders, including insomnia, sleep apnea, and restless legs syndrome, in patients with PN compared with control patients.

Results

Compared with controls, PN was associated with insomnia (adjusted hazard ratio [aHR] = 1.77; 95% CI = 1.48-2.12) and overall sleep disorder (aHR = 1.72; 95% CI = 1.46-2.02), but not with sleep apnea (aHR = 1.51; 95% CI = 0.93-2.44) or restless legs syndrome (aHR = 1.54; 95% CI = 0.92-2.57).

Limitations

As a retrospective cohort study, our analysis is subject to potential confounders not already included.

Conclusions

PN was associated with subsequent development of insomnia. Thus, clinicians should consider insomnia among patients with PN and develop strategies for treatment and prevention.

Incident Comorbidity, Resource Use, and All-Cause Mortality Associated with Prurigo Nodularis: A United Kingdom Retrospective Database Analysis

We described comorbidity, resource utilization, and mortality for patients with prurigo nodularis (PN) using data from the Clinical Practice Research Datalink. Patients with incident PN (2008-2018) were selected and matched to controls. Of 2,416 patients with PN, 2,409 (99.7%) were matched to controls. Prevalence of atopic dermatitis (relative risk [RR] = 2.571; 95% confidence interval [CI] = 2.356-2.806), depression (RR = 1.705; 95% CI = 1.566-1.856), anxiety (RR = 1.540; 95% CI = 1.407-1.686), coronary heart disease (RR = 1.575; 95% CI = 1.388-1.787), chronic kidney disease (RR = 1.529; 95% CI = 1.329-1.759), and type 2 diabetes mellitus (RR = 1.836; 95% CI = 1.597-2.111) was significantly higher for patients with PN. Subsequent risk of atopic dermatitis (hazard ratio = 6.58; 95% CI = 5.17- 8.37), depression (hazard ratio = 1.61; 95% CI = 1.30-1.99), and coronary heart disease (hazard ratio = 1.37; 95% CI = 1.09-1.74) were significantly increased. Resource utilization was increased in all settings: incidence rate ratio = 1.48 (95% CI = 1.47-1.49) for primary care, incident rate ratio = 1.80 (95% CI = 1.75-1.85) for inpatients, incident rate ratio = 2.15 (95% CI = 2.13-2.18) for outpatients, and incidence rate ratio = 1.32 (95% CI = 1.27-1.36) for accident and emergency. Respective cost ratios were 1.78 (95% CI = 1.67-1.90), 1.52 (95% CI = 1.20-1.94), 2.34 (95% CI = 2.13-2.58), and 1.55 (95% CI = 1.33-1.80). Total primary and secondary healthcare costs were £2,531 versus £1,333, a cost ratio of 1.62 (95% CI = 1.36-1.94). The adjusted hazard ratio for mortality was 1.37 (95% CI = 1.14-1.66). Patients with PN had significantly increased rates of comorbidity, healthcare resources utilization, and mortality compared with matched controls.

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.

[Chronic prurigo]

Chronic prurigo is a very debilitating skin condition characterized by the development of multiple pruriginous nodules, papules or plaques due to a prolonged scratching behavior as a result of chronic itch. Patients often experience anxiety, depression or sleep impairment leading to a substantial decrease in quality of life. Due to the complex pathophysiology and diversity in clinical presentation, managing chronic prurigo remains a challenge. Disease-specific guidelines provide appropriate diagnostic measures and recommend a step-wise therapeutic approach. With the increase of pharmaceutical interest in chronic prurigo, several innovative therapies including monoclonal antibodies and small molecules are currently being investigated for chronic prurigo. This continuing medical education (CME) article provides an overview on various aspects of chronic prurigo, especially on epidemiology, pathophysiology, clinical presentation, diagnostic and therapeutic approach, and innovate therapeutic options.

Zinc Oxide Patches Are a Highly Effective Treatment for Chronic Prurigo: A Randomized Split-Body Study

BACKGROUND

Chronic prurigo (CPG) presents with pruriginous lesions and reduced quality of life (QoL). Established treatment options are often unsatisfying. Little is known about the efficacy of topical occlusive treatments. Patients often report rapid relief of symptoms when using topical occlusive zinc oxide patches (ZOP). We, therefore, aimed to assess the efficacy of ZOP.

METHODS

In this randomized controlled split-body crossover study, 22 participants were analyzed, receiving three treatments sequentially: ZOP, topical betamethasone 17-valerate (topical glucocorticosteroids [TGCs]), and both ZOP and TGC combined (ZOP + TGC). Each intervention was applied to either the right or left side of the body for seven consecutive days. Outcomes were a count of active excoriated pruriginous lesions (APLs), itch, recurrence of APL, QoL, and treatment comfort. They were assessed through photographs and questionnaires: modified Prurigo Activity and Severity Score, modified Itchy Quality of Life Questionnaire, and Therapy Comfort Score.

RESULTS

We observed a significant reduction of 46% in APL count for ZOP (95% CI from 30% to 58%, p value: <0.0001). Similar reduction was seen for ZOP + TGC, and a lower reduction was seen for TGC alone (48% [95% CI from 33% to 60%, p value: <0.0001] vs. 26% [95% CI from 4% to 43%, p value: 0.02]). APL counts on the non-treated side remained stable. Significant reduction in itch was observed after all treatments, with the largest improvement for ZOP + TGC, followed by TGC and, lastly, ZOP alone (-2.3 units [95% CI from -3.5 to -1.1, p value: 0.00015] vs. -1.5 units [95% CI from -2.8 to -0.3, p value: 0.01 vs. -1.4 units [95% CI from -2.6 to -0.2, p value: 0.02]). QoL increased significantly after ZOP + TGC as well as after TGC (-8.3 units [95% CI from -13.6 to -3.1, p value: 0.0018] vs. -5.7 units [95% CI from -10.9 to -0.5, p value: 0.03]). A good subjective response concerning treatment comfort was observed.

CONCLUSION

ZOP are effective in reducing APL after 1 week of treatment. Adding TGC to ZOP did not add considerable benefit in reducing APL. All three treatments reduced itch and improved QoL, with the largest improvement shown by ZOP combined with TGC. Patients tolerated ZOP well and reported no adverse events. We therefore suggest ZOP combined with TGC as an effective, fast-acting, low-cost treatment for reducing APL and itch in patients with CPG.

Type 2 chronic inflammatory diseases: targets, therapies and unmet needs

Over the past two decades, significant progress in understanding of the pathogenesis of type 2 chronic inflammatory diseases has enabled the identification of compounds for more than 20 novel targets, which are approved or at various stages of development, finally facilitating a more targeted approach for the treatment of these disorders. Most of these newly identified pathogenic drivers of type 2 inflammation and their corresponding treatments are related to mast cells, eosinophils, T cells, B cells, epithelial cells and sensory nerves. Epithelial barrier defects and dysbiotic microbiomes represent exciting future drug targets for chronic type 2 inflammatory conditions. Here, we review common targets, current treatments and emerging therapies for the treatment of five major type 2 chronic inflammatory diseases - atopic dermatitis, chronic prurigo, chronic urticaria, asthma and chronic rhinosinusitis with nasal polyps - with a high need for targeted therapies. Unmet needs and future directions in the field are discussed.

Effectiveness of 0.1% mometasone furoate under hydrocolloid dressing versus 0.1% mometasone furoate in patients with lichen simplex chronicus

There was a lack of high-quality, evidence-based treatment for lichen simplex chronicus (LSC). Topical steroid under hydrocolloid dressing treatment was investigated mostly in observational studies without investigation of the cost-effectiveness and the methodology of application also varied without standardisation. To investigate the cost-effectiveness of topical steroid under hydrocolloid dressing in the treatment of moderate to severe lichen simplex chronicus (LSC). The study aimed to provide a clear methodology that was replicable. A single-blinded randomized controlled trial was carried out to compare the efficacy of 0.1% mometasone furoate cream with or without hydrocolloid dressing in patients suffering from moderate to severe LSC. Physician Global Assessment (PGA) score, Eczema Area and Severity Index (EASI) individual components score were assessed by a Dermatologist through clinical photos at week 0, 2, and 4. Pruritis Numerical Rating Scale (PNRS) was rated. Forty adult patients were recruited. The group with hydrocolloid dressing showed superior treatment efficacy. 20 out of 20 patients benefited from the hydrocolloid dressing with topical steroid while only 6 out of 20 patients benefited from topical steroid alone at week 2 regarding PGA. Similar result was obtained at week 4. Extra HK$ 132 was needed for each patient in hydrocolloid with topical steroid group. The number needed to treat (NNT) was 1.43 (95% CI: 1.42-1.44) at week 2 and 1.42 (95% CI: 1.41-1.44) at week 4 regarding PGA score improvement of ≥2. NNT analysis supported the cost-effectiveness of adjunctive hydrocolloid dressing usage as the first-line treatment in patients with moderate to severe LSC. This study added evidence to LSC treatment with a detailed and reproducible methodology.

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.

Efficacy and safety of vixarelimab, a human monoclonal oncostatin M receptor β antibody, in moderate-to-severe prurigo nodularis: a randomised, double-blind, placebo-controlled, phase 2a study

BACKGROUND

Prurigo nodularis is a chronic skin disease characterised by intensely pruritic, hyperkeratotic nodules. Vixarelimab, a human monoclonal antibody, binds to the beta subunit of the oncostatin M receptor, inhibiting signalling of both interleukin 31 and oncostatin M, two cytokine pathways that contribute to pruritus and nodule formation in prurigo nodularis.

METHODS

This double-blind, placebo-controlled, phase 2a trial was done at both private and academic dermatology outpatient research clinics across the United States and Canada (n = 40). Patient eligibility criteria included age 18-75 years, physician-documented diagnosis of prurigo nodularis minimum 6 months duration of prurigo nodularis, presence of at least 10 pruritic nodules approximately 0.5-2 cm in size on at least two different anatomical locations (excluding face and scalp) and involving the extremities, and presence of normal-appearing skin between nodules; atopic dermatitis as a comorbidity was exclusionary. Patients were required to have moderate-to-severe pruritus, defined as Worst Itch-Numeric Rating Scale (WI-NRS) score ≥7 at screening and LS-mean weekly WI-NRS score ≥5 for each of the 2 consecutive weeks immediately before randomisation. Participants were randomly assigned (1:1) to receive weekly subcutaneous vixarelimab 360 mg (720 mg loading dose) or placebo using stratification factors (sex and presence of atopy) and block size 4 through the IWRS system. Stratification by atopy status was based on the reported high prevalence of atopy in this population and the potential impact of atopy in the immunopathologic process in prurigo nodularis. Patients, investigators, study sponsor, and site staff were masked to study treatment. The primary efficacy endpoint was least squares (LS)-mean percent change from baseline (PCFB) at Week 8 in weekly average Worst Itch-Numeric Rating Scale (WI-NRS) score. The primary efficacy endpoint was analysed with ANCOVA including treatment as fixed effect, with baseline WI-NRS, and randomisation stratification factor as covariates. All randomised patients who had at least 1 dose of study drug or placebo were included in the Safety Analysis Set. This trial is registered at ClinicalTrials.gov, NCT03816891.

FINDINGS

Of 50 patients randomised between March 11, 2019 and January 31, 2020, 23 vixarelimab recipients and 26 placebo recipients comprised the modified intent-to-treat analysis population (baseline LS-mean [SD] WI-NRS score, 8.3 [1.05]). Outcomes at Week 8 for vixarelimab versus placebo included LS-mean PCFB in WI-NRS score, -50.6% versus -29.4% (LS-mean difference [95% CI], -21.2% [-40.82, -1.60]; p = 0.03); ≥4-point reduction in WI-NRS score, 52.2% (12/23) versus 30.8% (8/26) (p = 0.11); PN-IGA score of 0 or 1, 30.4% (7/23) versus 7.7% (2/26) (p = 0.03); LS-mean PCFB in pruritus VAS score, -54.4% versus -32.6% (p = 0.03); and LS-mean PCFB sleep loss reduction (improvement), -56.3% versus -30.0% (p = 0.02). No deaths, serious TEAEs, or TEAEs leading to dose interruption were reported. The percentage of vixarelimab recipients reporting any TEAE was 91.3% (21/23) versus 76.9% (20/26) of placebo recipients; drug-related TEAEs generally were similar between the two groups (vixarelimab, 43.5% [10/23]; placebo, 38.5% [10/26]).

INTERPRETATION

Vixarelimab demonstrated rapid reduction of pruritus and achievement of clear/almost clear skin in one-third of the patients by Week 8. Relief of itch and clearing of skin nodules represent two important potential therapeutic advances in the management of patients suffering from the debilitating disease Prurigo Nodularis.

FUNDING

Kiniksa Pharmaceuticals, Ltd.

Single-cell RNA sequencing reveals dysregulated fibroblast subclusters in prurigo nodularis

Prurigo nodularis (PN) is an intensely pruritic, chronic inflammatory skin disease that disproportionately affects black patients. However, the pathogenesis of PN is poorly understood. We performed single-cell transcriptomic profiling, ligand receptor analysis and cell trajectory analysis of 28,695 lesional and non-lesional PN skin cells to uncover disease-identifying cell compositions and genetic characteristics. We uncovered a dysregulated role for fibroblasts (FBs) and myofibroblasts as a key pathogenic element in PN, which were significantly increased in PN lesional skin. We defined seven unique subclusters of FBs in PN skin and observed a shift of PN lesional FBs towards a cancer-associated fibroblast (CAF)-like phenotype, with WNT5A+ CAFs increased in the skin of PN patients and similarly so in squamous cell carcinoma (SCC). A multicenter PN cohort study subsequently revealed an increased risk of SCC as well as additional CAF-associated malignancies in PN patients, including breast and colorectal cancers. Systemic fibroproliferative diseases were also upregulated in PN patients, including renal sclerosis and idiopathic pulmonary fibrosis. Ligand receptor analyses demonstrated increased FB1-derived WNT5A and periostin interactions with neuronal receptors MCAM and ITGAV, suggesting a fibroblast-neuronal axis in PN. Type I IFN responses in immune cells and increased angiogenesis/permeability in endothelial cells were also observed. As compared to atopic dermatitis (AD) and psoriasis (PSO) patients, increased mesenchymal dysregulation is unique to PN with an intermediate Th2/Th17 phenotype between atopic dermatitis and psoriasis. These findings identify a pathogenic role for CAFs in PN, including a novel targetable WNT5A+ fibroblast subpopulation and CAF-associated malignancies in PN patients.

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).

Chronic Nodular Prurigo: An Update on the Pathogenesis and Treatment

Chronic nodular prurigo (CNPG) is a recalcitrant chronic itchy disorder that affects the quality of life. It can be triggered by multiple etiologies, such as atopic dermatitis, diabetes, and chronic renal diseases. The mechanisms of CNPG are complicated and involved the interaction of the cutaneous, immune, and nervous systems. Diverse immune cells, including eosinophils, neutrophils, T cells, macrophages, and mast cells infiltrated the lesional skin of CNPG, which initiated the inflammatory cytokines and pruritogens release. In addition, the interaction between the immune cells and activated peripheral sensory nerve fibers by neurotransmitters caused neuroinflammation in the skin and intractable itch. This itch-scratch vicious cycle of CNPG results in disease exacerbation. CNPG is difficult to treat with traditional therapies. Recently, great advances have been made in the pathophysiology of both inflammation and pruritus transmission in CNPG. In this review, we summarize the updated mechanisms and novel therapies for CNPG.

Impact of Chronic Kidney Disease Severity on the Risk of Prurigo Nodularis: A Population-Based Cohort Study

While dialysis is linked with prurigo nodularis, little is known about the impact of non-dialysis chronic kidney disease on prurigo nodularis. The influence of chronic kidney disease on development of prurigo nodularis was measured using the Korean National Health Insurance and National Health Screening Program data, identifying 17,295,576 individuals without prior prurigo nodularis. Chronic kidney disease severity was determined by the estimated glomerular filtration rate (in ml/min/1.73 m²) calculated from serum creatinine, and proteinuria detected with urine dipstick. Prurigo nodularis incidence during follow-up was determined. Over a median follow-up period of 9.72 years, 58,599 individuals developed prurigo nodularis, with an incidence rate of 3.59 per 10,000 person-years. Among different variables, estimated glomerular filtration rate was the strongest risk factor for prurigo nodularis. Compared with estimated glomerular filtration rate ≥ 90, estimated glomerular filtration rate 15–29 (hazard ratio 1.31, 95% confidence interval 1.05–1.62) and end-stage renal disease (hazard ratio 1.46, 95% confidence interval 1.25–1.69) were associated with higher risks. The presence of proteinuria independently increased the risk of prurigo nodularis, increased risks associated with estimated glomerular filtration rate 15–29 and endstage renal disease, and caused risk associated with estimated glomerular filtration rate 30–59 to become significant. With differential impact of chronic kidney disease severity on the risk of prurigo nodularis, preservation of renal function would potentially translate into lower risk of prurigo nodularis.

Dupilumab for Chronic Prurigo in Different Backgrounds: A Case Series

Chronic prurigo (CPG) is a chronic inflammatory disease characterized by intense pruritus, and therapy is often challenging due to its unclear pathogenesis. Here, we report four patients with refractory CPG from different backgrounds who experienced failure of conventional therapy and were controlled with dupilumab, accompanied by a significant decrease in pruritus numerical rating scale, dermatology life quality index, and investigator global assessment, without adverse effects. Furthermore, dupilumab improved the condition of asthma in CPG patients along with an increase in asthma control test scores.

Modulation of the kappa and mu opioid axis for the treatment of chronic pruritus: A review of basic science and clinical implications

Introduction

Treating chronic pruritus is challenging for dermatologists due to the lack of therapeutic options. We review the effects of κ-opioid receptor (KOR) and μ-opioid receptor (MOR) in the modulation of itch, summarize evidence supporting the efficacy and safety of opioid receptor–targeting agents in chronic pruritus, and address clinical considerations.

Results

Preclinical studies have found neural pathways underlying detection, transmission, and modulation of itch signaling and spotlighted the importance of neuronal KOR and MOR in itch perception. Clinical reports suggest that opioid axis modulation may be the basis for the successful treatment of chronic itch. Several agents (MOR antagonist naltrexone; KOR agonists nalfurafine and difelikefalin; dual-acting KOR agonists/MOR antagonists butorphanol and nalbuphine) have been evaluated for treating chronic pruritus in case series, small studies, and clinical trials; nalbuphine has progressed through preliminary (phase II/III) studies in uremic pruritus and prurigo nodularis. The antipruritic efficacy of these agents has been observed across multiple disorders with disparate etiologies, suggesting the potential utility of this class to provide a unified approach to chronic pruritus treatment.

Conclusions

The relative safety of these agents, including a reduced potential for dependence versus MOR-agonist analgesics, should help overcome resistance to the use of opioid receptor–targeting agents in chronic pruritus treatment.

Immunotargets and Therapy for Prurigo Nodularis

Prurigo nodularis is a chronic inflammatory skin disease consisting of severely pruritic nodules that can be very debilitating for patients. The basis of this skin condition is immunological dysregulation and neural amplification, driven by T-lymphocytes, mast cells, eosinophilic granulocytes, macrophages, and cytokines mediating itchy processes. Further complicating this already taxing diagnosis is the lack of approved treatment and consensus on management; although there are off-label treatments utilized as therapy. Immunomodulators are the cornerstone of treatment for PN, and additional novel therapies targeting key players in the immunological cascade are currently undergoing investigation. In this review, we will highlight targets of the immune cascade and explore current immunomodulating treatments as well as immunotherapies on the horizon for the management of prurigo nodularis.

Epidemiology of prurigo nodularis in England: a retrospective database analysis

OBJECTIVES

Prurigo nodularis is a debilitating skin condition that is classified as rare by the Genetic and Rare Diseases Information Center (GARD) and National Organization for Rare Diseases (NORD). There are no estimates of the prevalence of prurigo nodularis in England. We aimed to address this data gap by describing the epidemiology of prurigo nodularis in a representative dataset derived from the English National Health Service.

METHODS

The study utilised data from the Clinical Practice Research Datalink linked to Hospital Episode Statistics inpatient data. Patients with a diagnosis of prurigo nodularis were selected by clinical code in the primary care or inpatient datasets. Case definition was based on a minimum of two distinct diagnoses to maximize specificity. Point prevalence was calculated for the midpoint of 2018 and incidence rates from 2008-2018 presented. For those classified as incident cases, demographic and clinical characteristics were reported. In sensitivity analyses the case definition was modified to relax the multiple diagnosis criteria and to restrict cases to those diagnosed within a maximum of four or ten years of the midpoint prevalence date.

RESULTS

11,656 patients within the dataset had at least one prurigo nodularis diagnosis. Following application of the relevant inclusion criteria 2,743 patients formed the point prevalent cohort; an estimated prevalence of 3.27 patients per 10,000 (95% CI 3.15-3.40). In sensitivity analyses the estimated prevalence ranged from 2.24 (2.14-2.34) to 6.98 (6.8-7.16). Incidence over the study period was 2.88 per 100,000 patient years. Comorbidity was relatively high in this population notably for atopic dermatitis (52.2%), depression (41.1%) and anxiety (35.4%).

CONCLUSION

This study supports the NORD/GARD classification of prurigo nodularis as a rare disease with a prevalence of 3.27 patients per 10,000 equating to 18,471 patients living with the disease in England in 2018. The relatively high prevalence of comorbidity observed for these patients may increase the complexity of management.

Itch: Epidemiology, clinical presentation, and diagnostic workup

Itch, or pruritus, is the uncomfortable sensation underlying the desire to scratch. Itch is a very common complaint in the general population that can result from dermatologic, systemic (eg, renal, hepatobiliary, endocrine), paraneoplastic, neuropathic, and psychogenic etiologies. Chronic itch is associated with significant sleep disturbances and profoundly reduces overall quality of life. Certain populations, including elderly and African Americans, are at increased risk of experiencing heightened burden of itch. Because of the variable clinical presentation and wide-ranging etiologies, itch presents a challenge for clinicians. The initial evaluation should include a complete blood count, with differential, hepatic, renal, and thyroid function testing along with diabetes screening. Further testing should be guided by history and physical examination findings. There should be a heightened concern for underlying malignancy in individuals older than 60 years of age who have a history of liver disease and diffuse itch less than 12 months of duration. For individuals with chronic pruritus of unknown origin, increased blood eosinophils may serve as a biomarker of T helper cell type 2 polarization and response to immunomodulator therapies. In this first part of a 2-part continuing medical education series, we describe the broader epidemiology and specific conditions associated with itch and the clinical presentation and diagnostic workup for patients with itch.

Epidemiology, Comorbidities, and Prescription Patterns of Korean Prurigo Nodularis Patients: A Multi-Institution Study

Prurigo nodularis (PN) is a chronic dermatosis typified by extraordinarily itchy nodules. However, little is known of the nature and extent of PN in Asian people. This study aimed to describe the epidemiology, comorbidities, and prescription pattern of PN in Koreans based on a large dermatology outpatient cohort. Patients with PN were identified from the Catholic Medical Center (CMC) clinical data warehouse. Anonymized data on age, sex, diagnostic codes, prescriptions, visitation dates, and other relevant parameters were collected. Pearson correlation analysis was used to calculate the correlation between PN prevalence and patient age. Conditional logistic regression modeling was adopted to measure the comorbidity risk of PN. A total of 3591 patients with PN were identified at the Catholic Medical Center Health System dermatology outpatient clinic in the period 2007–2020. A comparison of the study patients with age- and sex-matched controls (dermatology outpatients without PN) indicated that PN was associated with various comorbidities including chronic kidney disease (adjusted odds ratio (aOR), 1.48; 95% confidence interval (CI), 1.29–1.70), dyslipidemia (aOR, 1.88; 95% CI, 1.56–2.27), type 2 diabetes mellitus (aOR, 1.37; 95% CI, 1.22–1.54), arterial hypertension (aOR, 1.50; 95% CI, 1.30–1.73), autoimmune thyroiditis (aOR, 2.43; 95% CI, 1.42–4.16), non-Hodgkin’s lymphoma (aOR, 1.95; 95% CI, 1.23–3.07), and atopic dermatitis (aOR, 2.16, 95% CI, 1.91–2.45). Regarding prescription patterns, topical steroids were most favored, followed by topical calcineurin inhibitors; oral antihistamines were the most preferred systemic agent for PN. PN is a relatively rare but significant disease among Korean dermatology outpatients with a high comorbidity burden compared to dermatology outpatients without PN. There is great need for breakthroughs in PN treatment.