The burden in chronic prurigo: patients with chronic prurigo suffer more than patients with chronic pruritus on non-lesional skin: A comparative, retrospective, explorative statistical analysis of 4,484 patients in a real-world cohort

Dupilumab improves pruritus and skin lesions in patients with prurigo nodularis: Pooled results from 2 phase 3 trials (LIBERTY-PN PRIME and PRIME2)

Background

Phase 3 PRIME/PRIME2 trials independently demonstrated efficacy and an acceptable safety profile of dupilumab adults with moderate-to-severe prurigo nodularis.

Objective

To obtain a more precise estimate of onset and magnitude of treatment effect using PRIME/PRIME2 pooled data.

Methods

In PRIME/PRIME2, patients were randomized to dupilumab or placebo for 24 weeks. Pooled analysis assessed proportion of patients achieving clinically meaningful improvement in itch, clear/almost-clear skin, or both; at weeks 12 and 24; overall and by demographic subgroups and changes from baseline to week 24 in symptoms, signs, and quality of life.

Results

Patients receiving dupilumab (n = 153) vs placebo (n = 158) experienced significant improvements in all tested endpoints. At week 24, 90 (58.8%) dupilumab-treated vs 30 (19.0%) placebo-treated patients achieved clinically meaningful improvement in itch, 71 (46.4%) vs 27 (17.1%) clear/almost clear skin, and 54 (35.3%) vs 14 (8.9%) achieved both (P < .0001 for all). Treatment benefits were independent of baseline demographics. Safety to week 36 was generally consistent with the known dupilumab safety profile.

Limitations

On-treatment data limited to 24 weeks.

Conclusions

Pooled analysis confirmed improvements reported in individual trials and revealed earlier effect onset in itch and skin pain. Dupilumab treatment showed benefits across demographics.

[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.

Dermatological patients with itch report more stress, stigmatization experience, anxiety and depression compared to patients without itch: Results from a European multi-centre study

BACKGROUND

Itch as the most common symptom in dermatology has been shown to be related to psychological factors such as stress, anxiety and depression. Moreover, associations were found between perceived stigmatization and itch. However, studies investigating the differences between patients with dermatoses with and without itch regarding perceived stress, stigmatization, anxiety and depression are missing. Therefore, one of the aims of the second study of the European Society for Dermatology and Psychiatry (ESDaP study II) was to investigate these relationships in a large cohort of patients with different itchy dermatoses.

RESULTS

3399 patients with 14 different itchy dermatoses were recruited at 22 centres in 17 European countries. They filled in questionnaires to assess perceived stigmatization, stress, signs of clinically relevant anxiety or depression, itch-related quality of life, the overall health status, itch duration, frequency and intensity. The most significant association between the severity of itching and the perception of stress was observed among individuals with rosacea (correlation coefficient r = 0.314). Similarly, the strongest links between itch intensity and experiences of stigmatization, anxiety, and depression were found in patients with seborrheic dermatitis (correlation coefficients r = 0.317, r = 0.356, and r = 0.400, respectively). Utilizing a stepwise linear regression analysis, it was determined that within the entire patient cohort, 9.3% of the variation in itch intensity could be accounted for by factors including gender, levels of anxiety, depression, and perceived stigmatization. Females and individuals with elevated anxiety, depression, and perceived stigmatization scores reported more pronounced itch intensities compared to those with contrary attributes.

CONCLUSION

This study underscores the connection between experiencing itch and its intensity and the psychological strain it places on individuals. Consequently, psychological interventions should encompass both addressing the itch itself and the interconnected psychological factors. In specific cases, it becomes imperative for dermatologists to direct individuals towards suitable healthcare resources to undergo further psychological assessment.

Estimating meaningful change thresholds for Skin Pain-Numeric Rating Scale, Sleep-Numeric Rating Scale and Dermatology Life Quality Index in patients with prurigo nodularis

BACKGROUND

Prurigo nodularis (PN) is characterized by intensely itchy nodules/lesions and skin pain, which can have a substantial impact on health-related quality of life (HRQoL). Treatment benefits on such symptoms and impacts are best assessed in trials using patient-reported outcome (PROs) instruments such as Skin Pain Numerical Rating Scale (NRS), Sleep-NRS and Dermatology Life Quality Index (DLQI). However, no guidance exists for interpreting meaningful changes in scores using these PROs in patients with PN.

OBJECTIVES

The main objective was to derive within-patient (responder definition) and between-group improvement thresholds for interpreting Skin Pain-NRS, Sleep-NRS and DLQI total scores in patients with PN. The measurement properties of the three PROs were also evaluated.

METHODS

Intention-to-treat (ITT), blinded and pooled data were used from the Phase 3 PRIME (NCT04183335) and PRIME2 (NCT04202679) studies evaluating the efficacy of dupilumab in adult patients with PN. Anchor- and distribution-based methods were applied to derive responder definition and between-group thresholds for Skin Pain-NRS, Sleep-NRS and DLQI. Data were additionally used to examine the instrument measurement properties, including reliability, validity and responsiveness.

RESULTS

A total of 311 patients (mean age 49.5 years, 65.3% female) were included in the pooled ITT population. The within-patient improvement threshold for Skin Pain-NRS was estimated as 4.0 points, 2.0 points for Sleep-NRS and 9.0 points for DLQI total score. A 1.5-point improvement in Skin Pain-NRS scores, 1.0-point in Sleep-NRS and 4.0-point in DLQI indicated a between-group meaningful change. Adequate to good psychometric properties were demonstrated for all three instruments.

CONCLUSIONS

The results of this study can aid interpretation of Skin Pain-NRS, Sleep-NRS and DLQI scores in patients with PN in both clinical trials and clinical practice to better understand and treat PN-related skin pain and the impact of PN on sleep quality and HRQoL.

Phenotyping peripheral neuropathies with and without pruritus: a cross-sectional multicenter study

ABSTRACT

Pruritus often escapes physicians' attention in patients with peripheral neuropathy (PNP). Here we aimed to characterize neuropathic pruritus in a cohort of 191 patients with PNP (large, mixed, or small fiber) and 57 control subjects with deep phenotyping in a multicenter cross-sectional observational study at 3 German sites. All participants underwent thorough neurological examination, nerve conduction studies, quantitative sensory testing, and skin biopsies to assess intraepidermal nerve fiber density. Patients filled in a set of questionnaires assessing the characteristics of pruritus and pain, the presence of depression and anxiety, and quality of life. Based on the severity of pruritus and pain, patients were grouped into 4 groups: "pruritus," "pain," "pruritus and pain," and "no pruritus/no pain." Although 11% (21/191) of patients reported pruritus as their only symptom, further 34.6% (66/191) reported pruritus and pain. Patients with pain (with or without pruritus) were more affected by anxiety, depression, and reduced quality of life than control subjects. Patients with pruritus (with and without pain) had increases in cold detection threshold, showing Aδ-fiber dysfunction. The pruritus group had lower intraepidermal nerve fiber density at the thigh, concomitant with a more proximal distribution of symptoms compared with the other PNP groups. Stratification of patients with PNP by using cross-sectional datasets and multinominal logistic regression analysis revealed distinct patterns for the patient groups. Together, our study sheds light on the presence of neuropathic pruritus in patients with PNP and its relationship with neuropathic pain, outlines the sensory and structural abnormalities associated with neuropathic pruritus, and highlights its impact on anxiety levels.

Chronische Prurigo

Die chronische Prurigo (CPG) ist eine neuroinflammatorische Dermatose, die durch langanhaltenden Pruritus von mehr als 6 Wochen, pruriginösen Hautläsionen und wiederholtem Kratzen gekennzeichnet ist. Patienten mit CPG leiden unter erheblichen psychischen Belastungen und deutlich spürbarer Beeinträchtigung ihrer Lebensqualität. Der am häufigsten vorkommende Subtyp der CPG ist die chronisch noduläre Prurigo (CNPG; auch Prurigo nodularis genannt).

Neben den klinischen Merkmalen der CPG und der Krankheitslast bietet dieser CME‐Artikel einen Überblick über die bedeutenden Fortschritte im Verständnis der Pathophysiologie, einschließlich der damit verbundenen therapeutischen Optionen der CPG. Dupilumab ist die erste zugelassene Therapie für die moderate und schwere CNPG, die bisher von der Europäischen Arzneimittelagentur (EMA) und der US‐amerikanischen Food & Drug Administration (FDA) zugelassen wurde. Des Weiteren werden weitere Wirkstoffe hervorgehoben, die derzeit in klinischen, randomisierten, placebokontrollierten Phase‐II‐ und Phase‐III‐Studien untersucht werden. Dazu gehören Biologika wie Nemolizumab (Anti‐IL‐31‐RA‐mAk), Vixarelimab/KPL‐716 (Anti‐Oncostatin‐M Rezeptor β‐mAk) und Barzolvolimab/CDX‐0159 (Anti‐KIT‐mAK), Januskinase‐Inhibitoren wie Povorcitinib/INCB054707 und Abrocitinib sowie Opiodmodulatoren wie Nalbuphin.

Chronic Prurigo

Chronic prurigo (CPG) is a neuroinflammatory dermatosis characterized by prolonged pruritus lasting more than 6 weeks, pruriginous skin lesions, and repeated scratching. Patients with CPG suffer significantly from psychological distress and a marked impairment in their quality of life. The most common subtype of CPG is chronic nodular prurigo (CNPG, also called prurigo nodularis). In addition to the clinical features of CPG and the burden of disease, this CME article provides an overview of the significant advances in understanding the pathophysiology, including the associated therapeutic options for CPG. Dupilumab is the first approved therapy for moderate and severe CNPG to date from the European Medicines Agency (EMA) and the US Food & Drug Administration (FDA). It also highlights other agents currently being studied in Phase II and Phase III clinical, randomized, placebo-controlled trials. These include biologics such as nemolizumab (anti-IL-31-RA-mAb), vixarelimab/KPL-716 (anti-Oncostatin-M receptor β-mAb), and barzolvolimab/CDX-0159 (anti-KIT-mAb), as well as Janus kinase inhibitors such as povorcitinib/INCB054707 and abrocitinib, and opioid modulators such as nalbuphine.

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.

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.

[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.

Phase 3 Trial of Nemolizumab in Patients with Prurigo Nodularis

BACKGROUND

Prurigo nodularis is a chronic, debilitating, and severely pruritic neuroimmunologic skin disease. Nemolizumab, an interleukin-31 receptor alpha antagonist, down-regulates key pathways in the pathogenesis of prurigo nodularis.

METHODS

In this phase 3, double-blind, multicenter, randomized trial, we assigned adults with moderate-to-severe prurigo nodularis to receive an initial 60-mg dose of nemolizumab followed by subcutaneous injections of 30 mg or 60 mg (depending on baseline weight) every 4 weeks for 16 weeks or matching placebo. The primary end points were an itch response (a reduction of ≥4 points on the Peak Pruritus Numerical Rating Scale [PP-NRS; scores range from 0 to 10, with higher scores indicating more severe itch]) and an Investigator's Global Assessment (IGA) response (a score of 0 [clear] or 1 [almost clear] on the IGA [scores range from 0 to 4] and a reduction from baseline to week 16 of ≥2 points). There were five key secondary end points.

RESULTS

A total of 274 patients underwent randomization; 183 were assigned to the nemolizumab group, and 91 to the placebo group. Treatment efficacy was shown with respect to both primary end points at week 16; a greater percentage of patients in the nemolizumab group than in the placebo group had an itch response (56.3% vs. 20.9%; strata-adjusted difference, 37.4 percentage points; 95% confidence interval [CI], 26.3 to 48.5), and a greater percentage in the nemolizumab group had an IGA response (37.7% vs. 11.0%; strata-adjusted difference, 28.5 percentage points; 95% CI, 18.8 to 38.2) (P<0.001 for both comparisons). Benefits were observed for the five key secondary end points: itch response at week 4 (41.0% vs. 7.7%), PP-NRS score of less than 2 at week 4 (19.7% vs. 2.2%) and week 16 (35.0% vs. 7.7%), and an improvement of 4 or more points on the sleep disturbance numerical rating scale (range, 0 [no sleep loss] to 10 [unable to sleep at all]) at week 4 (37.2% vs. 9.9%) and week 16 (51.9% vs. 20.9%) (P<0.001 for all comparisons). The most common individual adverse events were headache (6.6% vs. 4.4%) and atopic dermatitis (5.5% vs. 0%).

CONCLUSIONS

Nemolizumab monotherapy significantly reduced the signs and symptoms of prurigo nodularis. (Funded by Galderma; ClinicalTrials.gov number, NCT04501679; EudraCT number, 2019-004789-17.).

Clinical aspects and management of chronic itch

Chronic pruritus (CP) (ie, itch that persists for more than 6 weeks) poses significant challenges to patients' health and quality of life. It is a common reason for visits to dermatologists and general practitioners and can be caused by a range of conditions, including systemic diseases such as chronic kidney disease or liver diseases, malignancies, neuropathic conditions, and dermatoses such as atopic dermatitis. CP often does not develop in parallel with the course of the disease and can become an entity of its own, which must be treated with antipruritic drugs, even if the underlying cause is already under therapy. Depending on the etiology of CP, different pathways in the pathogenesis have been analyzed recently, following which new treatments have been developed and tested in randomized controlled trials. This article discusses the recent results of these studies and highlights how best to manage health care for patients with CP.

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 .

Cost-effectiveness and Quality of Specialized and Routine Care in a German Cohort of Patients with Chronic Pruritus

Chronic pruritus is a prevalent interdisciplinary symptom with a strong influence on health-related quality of life. Patients need extensive diagnostics and long-term treatment. This retrospective and prospective cohort study compared routine and university-based specialized care in terms of cost-effectiveness and patient benefit. Direct medical and non-medical costs and patient-reported outcomes (PRO; pruritus intensity, quality of life, treatment needs and benefits) were assessed. Data analyses were conducted using descriptive methods and non-parametric statistical tests. A total of 300 adult patients (54.3% female) participated in the study. Six months after the treatment start in a specialized German pruritus care unit, the total costs were significantly reduced (mean total costs 686 € vs 433 € per patient per half year (total cohort); p <  0.001; mean out-of-pocket costs 198 € vs 124 € per half year (total cohort), p <  0.001). Pruritus intensity (numerical rating  scale 5.3 vs 3.7, p < 0.001), quality of life (Dermatology Life Quality Index 8.9 vs 5.7, p < 0.001) and patient benefit (Patient Benefit Index Pruritus 1.2 vs 2.1, p < 0.001) improved significantly (total  cohort). The results of this study show, that treatment of chronic pruritus patients in a specialized itch centre leads to an improvement in patient  benefit and reduces the economic burden at the same time.

Introduction of a Specific Dermatological Rehabilitation Programme for Patients with Chronic Pruritus: A Pilot Study

Chronic pruritus is a common symptom, associated with several severe medical conditions, great psychological burden, and reduced quality of life. It also poses socio-economic challenges concerning patients' work loss and healthcare costs. In Germany, medical rehabilitation programmes represent an integral part of the medical care of patients with chronic inflammatory skin diseases. However, such programmes play only a rudimentary role in the treatment of other dermatological diseases, such as dermatological oncology, genetic skin diseases, and chronic pruritus. Therefore, a specific antipruritic dermatological rehabilitation programme was developed in cooperation between the Department of Dermatology of the Medical Rehabilitation Center Bad Bentheim and the Center for Chronic Pruritus of the University Hospital of Muenster, Germany. This prospective study compared short-term patient-reported outcomes (n = 121) at the beginning and end of the rehabilitation programme. The majority of subjects had chronic pruritus on primary diseased, inflamed skin. Significant improvements in pruritus intensity (p ≤ 0.001), quality of life (p ≤ 0.001), anxiety symptoms (p ≤ 0.001) and depression (p ≤ 0.001), as well as an overall patient-relevant benefit (Patient Benefit Index 2.6 ± 1.06) and treatment-related patients' satisfaction, were shown. This suggests that implementation of this standardized rehabilitation programme for treatment of patients with chronic pruritus was successful.

Nemolizumab efficacy in prurigo nodularis: onset of action on itch and sleep disturbances

BACKGROUND

Patients with prurigo nodularis (PN) have multiple itchy nodules, impaired quality of life and sleep deprivation. Prurigo nodularis patients have a high burden of disease, primarily due to the intensity of the itch. It is reasonable to expect that rapid relief of itch - and associated improvement of sleep - are highly valued clinical outcomes for patients. Nemolizumab is an IL-31A-receptor inhibitor that modulates the neuroimmune response with reported positive efficacy and safety data in a phase 2 study of PN.

OBJECTIVES

To evaluate the onset of action of nemolizumab on itch and sleep disturbances.

METHODS

Post hoc analysis of a phase 2 trial of nemolizumab 0.5 mg/kg SC vs. placebo in patients (n = 70) with moderate-to-severe PN (≥20 nodules) and severe pruritus (NRS ≥ 7). Time to significant reduction was assessed for peak pruritus (PP) and sleep disturbance (SD) using numerical rating scales (NRS), also assessed was scratching time during sleep.

RESULTS

Nemolizumab significantly reduced itch vs. placebo within 48 h (PP NRS -19.5% vs. -5.8%, respectively, P = 0.014). Significant difference between nemolizumab and placebo in reducing itch by ≥4 on PP NRS was achieved at Day 3 (23.5% vs. 0%, P < 0.001). A significant difference in SD NRS was reported by Day 4 (-24.0% vs. -4.3% placebo, P = 0.012). In addition, there was a separation between groups in SD responders (decrease of ≥4 points) in favour of nemolizumab by Day 2 (8.8% vs. 0%, P = 0.037). Sleep continued improving through Week 4, when there was a -56.0% reduction in SD NRS vs. -22.9% placebo (P < 0.001). Actigraphy data showed improvement in scratch/sleep duration for nemolizumab vs. placebo, respectively, by Week 1 (-32.15 vs. +28.15 min/h, P = 0.001).

CONCLUSION

Nemolizumab has a rapid and robust onset of action in PN with itch reduction and improvement of sleep within 48 h.

[Update on the treatment of chronic prurigo]

Chronic prurigo is an inflammatory dermatosis defined by the presence of chronic pruritus and single to multiple symmetrically distributed pruriginous lesions such as nodules, papules, and plaques. Various dermatological, systemic, neurological, and/or psychiatric diseases are associated with chronic prurigo. The care of these patients is very complex due to the multifactorial character and also because of the sometimes very pronounced consequences such as an impairment of quality of life with sleep disorders. Furthermore, there are no approved therapies. The current guideline-based treatment recommendations include topical application of steroids, capsaicin, calcineurin inhibitors, phototherapy, and systemic use of gabapentinoids, μ‑opioid receptor antagonists, immunosuppressants, or dupilumab. Results from randomized controlled trials and case series on new therapies including biologics (e.g., nemolizumab) and Janus kinase inhibitors are promising. This article provides an overview of currently available treatment options and discusses the latest data on the efficacy of future therapies.

The emerging role of the neuroimmune cytokine interleukin-31 in chronic inflammatory skin diseases

Chronic inflammatory skin diseases pose significant challenges for both patients and clinicians worldwide. Atopic dermatitis (AD), the most common of these diseases, affects up to 8% of the adult population depending on geographic location and demographic group, while prurigo nodularis (PN) is a less common disease that causes significant burden. In these inflammatory skin conditions, pruritus is a cardinal symptom. Interleukin 31 (IL-31), described as a neuroimmune modulator, has been shown to have a prominent role in both inflammation and itch. IL-31 acts through a receptor complex consisting of IL-31 receptor α (IL-31RA) and oncostatin M receptor β (OSMRβ). IL-31 is produced by a variety of cells, including type 2 helper T cells, and IL-31 signaling can activate three important pathways: JAK/STAT, P13K/AKT, and ERK/MAPK. IL-31 is elevated in AD and PN, and is thought to induce chemokine genes CCL1, CCL17, and CCL22. The chemokines recruit T cells to affected skin, where more IL-31 is secreted. The IL-31 receptor complex is also abundant in dorsal root ganglia in human tissue, home of primary sensory neurons and the distal source of "itch sensations". IL-31 and its receptor complex have an important role in chronic inflammatory diseases, including AD and PN, and blocking the IL-31/IL-31RA signaling may represent an important new therapeutic approach for these diseases, which continue to have significant unmet medical needs.

Worst Itch Numerical Rating Scale for Prurigo Nodularis: A Psychometric Evaluation

BACKGROUND

Study TR03 evaluated the safety and efficacy of nalbuphine ER for prurigo nodularis (PN) (NCT02174419).

OBJECTIVE

We conducted supplementary analyses to assess the psychometric properties of the Worst Itch Numeric Rating Scale (WI-NRS), the TR03 primary endpoint.

METHODS

Study TR03 was a double-blind, placebo-controlled, phase 2 trial in PN patients with documented scores ≥5 on the WI-NRS (0 [no itch]-10 [worst itch imaginable]) on ≥5 of 7 days before baseline. Using TR03 data, the WI-NRS's psychometric properties, including reliability, validity, and ability to detect change, were evaluated. A responder threshold was estimated to facilitate interpretation of WI-NRS score changes.

RESULTS

Among 62 treated patients, improvements in mean [SD] (median) WI-NRS scores were observed between baseline (8.2 [1.21] (8.1)) and Week 10 (5.8 [2.43] (6.0)). The WI-NRS had an intraclass correlation coefficient of 0.96 (95% confidence interval, 0.93-0.98) in 42 patients who had stable Itch verbal rating scale (VRS) scores from Week 9-10, supporting strong test-retest reliability. Construct validity was supported, with strong correlations at Week 10 with Average Itch NRS (r=0.87) and Itch VRS single-day/weekly mean scores (r=0.81/0.89) and moderate correlations with ItchyQoL^TM total/domain scores (r=0.41-0.43). The WI-NRS discriminated between predefined severity subgroups based on the Itch VRS and detected changes in itching severity (effect-size estimate: -2.05; standardized response mean: -1.21). An anchor-based threshold based on a two-category improvement in the single-day Itch VRS suggests a responder threshold of ≥3.8 points (~40% improvement).

CONCLUSIONS

The WI-NRS demonstrates good measurement properties, supporting its use in evaluating treatment change in PN.

Itch in Adult Population with Type 2 Diabetes Mellitus: Clinical Profile, Pathogenesis and Disease-Related Burden in a Cross-Sectional Study

BACKGROUND

Despite growing interest in itch, data regarding itch in type 2 diabetes mellitus (DM2) are still limited, and mostly based on outdated studies. This study aimed to evaluate the clinical characteristics of itch in the adult population with DM2 and explore potential underlying causes.

METHODS

The study group consisted of 109 adult patients with DM2. Standardized questionnaires were completed in order to assess the itch intensity [Numerical Rating Scale (three days, 24hours) (NRS)] and the Four-item Itch Questionnaire (4IIQ) and to assess the psychological impact of itch [ItchyQoL, Six-Item Stigmatization Scale (6-ISS), Hospital Anxiety and Depression Scale (HADS)]. Skin dryness was evaluated clinically and by non-invasive assessment of epidermis moisturizing. Neuropathy was assessed using the clinical Katzenwadel neuropathy scale.

RESULTS

Itch occurred in 35.8% of adult patients with DM2, with NRSmax three days 6.31 ± 2.16 and 8.1 ± 3.5 points in 4IIQ. Itchy patients have had significantly higher FPG levels compared with the non-itchy population (p = 0.01). Patients with itch had a significantly higher possibility of neuropathy compared with non-itchy subjects (p < 0.01). Skin xerosis was significantly more advanced in patients with itch compared to those without (p < 0.01). The mean ItchyQol score was assessed as 41.2 ± 13.4 points, indicating mild life quality impairment and correlated positively with itch intensity. Itchy subjects had significantly higher scores in both anxiety and depression dimensions of HADS (in each p < 0.01).

CONCLUSIONS

We suggest that the primary cause of itch is prolonged poor diabetes control with altered glucose and insulin levels, subsequently causing skin dryness and neuropathy in long-lasting DM2.

Clinical characteristics and disease burden in prurigo nodularis

BACKGROUND

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

AIM

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

METHODS

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

RESULTS

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

CONCLUSIONS

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