Prurigo nodularis: Epidemiology and clinical features

Prurigo nodularis and the microbiome

Prurigo nodularis (PN) is a chronic skin condition that profoundly impacts quality of life. Histopathological studies of itchy hyperkeratotic nodules show dense infiltrates of T lymphocytes, mast cells, and eosinophils. A robust inflammatory response is implicated, coupled with key changes in neuronal plasticity that affect nerve fiber architecture and function. The microbial community in PN lesions exhibits a distinct composition, marked by decreased α-diversity and a prominent increase in Staphylococcus aureus (S aureus). This alteration appears to contribute to the disease's pathophysiology, causing further disruption of the skin barrier, immune dysregulation, and neuronal plasticity. There is ample evidence that virulence factors of S aureus promote Th2, Th17, and Th22 cytokine production, which are key to PN. In addition, S aureus V8 protease (Endoproteinase Glu-C) has recently been identified to trigger robust itch by activating protease-activated receptor 1 (PAR1) on sensory neurons. This review underscores the complex interplay between the altered microbiome and the itch-scratch cycle of PN, providing insights into potential therapeutics targeting the skin microbiome. A multidisciplinary approach is crucial for providing relief to individuals suffering from this skin condition.

Incidence and prevalence of prurigo nodularis and associated comorbidities in Denmark from 1998 to 2021

BACKGROUND

Prurigo nodularis (PN) is a chronic skin condition characterized by intense itching from nodular skin lesions. Despite its impact on patients' quality of life, limited data exist on its epidemiology.

OBJECTIVES

To estimate the incidence and prevalence of hospital-diagnosed PN and to explore the burden of associated comorbidities.

METHODS

A national register-based study in Denmark was conducted using data from Danish national health registers to determine the incidence and prevalence of PN diagnosed in hospitals from 1998 to 2021 and to explore the occurrence of comorbidities.

RESULTS

In total, we identified 1209 individuals diagnosed with PN. The mean age of onset was 45 years, with a female predominance of 58% (696/1209). The prevalence of PN increased over the studied period, reaching 14.1 per 100 000 individuals by 2021. Comorbidities such as chronic kidney disease had higher odds ratios preceding the diagnosis of PN, whereas the odds ratios for atopic dermatitis, mood disorders and depressive disorders increased following the onset of PN.

CONCLUSION

The findings indicate a significant association between PN and various comorbidities, emphasizing the need for multidisciplinary care. The increase in prevalence suggests a growing burden of disease. Although the study may underestimate the true prevalence of PN because of reliance on hospital records, it reveals a rising rate prevalence of PN and associated comorbidities in Denmark. The observed high prevalence of mental health problems in individuals with PN should be a focus of concern for the treating physicians.

Kyrle disease: a systematic review of clinical features, diagnostic approaches, dermatoscopic insights, systemic associations, and therapeutic strategies

Kyrle disease (KD) is a rare dermatologic condition characterized by hyperkeratotic papules with central keratotic plugs, often associated with systemic conditions such as diabetes and chronic kidney disease. Due to its clinical overlap with other dermatologic disorders, KD is frequently misdiagnosed. Diagnosis primarily relies on characteristic histopathological findings, with dermoscopy serving as a valuable adjunct for clinical assessment. This systematic review highlights KD's clinical features, systemic associations, dermoscopy findings, differential diagnosis, and current treatment approaches. While some therapies have shown promise, the lack of standardized management underscores the need for further research. By consolidating the existing literature, this systematic review emphasizes the importance of a multidisciplinary approach in managing KD and calls for future studies to establish standardized diagnostic and therapeutic protocols to improve patient outcomes.

Functional magnetic resonance imaging in prurigo nodularis: A call to study neural sensitization phenomena

Prurigo nodularis is a chronic pruritic, inflammatory skin condition characterized by nodular skin lesions in a typical distribution pattern caused by various dermatologic and/or nondermatologic conditions. In recent years, significant advances have been made in the understanding of the cutaneous pathophysiology of prurigo nodularis, resulting in novel treatment options such as interleukin-4, -13, -17, and -31 or Janus kinase inhibitors. Many aspects of the neurophysiology are largely unknown, including the processing in the central structural and functional network involved in prurigo nodularis. Functional neuroimaging allows noninvasive assessment of brain function and structure. Due to its high spatial resolution and temporal precision, functional magnetic resonance imaging has proven to be a suitable method for exploring neural mechanisms and assessing pharmacologic effects in dermatologic research. In this systematic review, the current knowledge of functional magnetic resonance imaging in the context of prurigo nodularis and its centrally active treatment options is summarized.

Current Status of Prurigo Nodularis in Japan: A Retrospective Study Using a Health Insurance Claims Database

Background/Objectives: Prurigo nodularis (PN) is associated with considerable disease burden. Limited information exists about the epidemiology, treatment patterns, and impact of PN. This retrospective study used Japanese health insurance claims data to investigate the prevalence and incidence of PN from 2006 to 2021. Methods: A cross-sectional study design was used to estimate prevalence and incidence longitudinally; a cohort design was used to assess comorbidities, treatment patterns, and healthcare resource utilization (HCRU). Results: Over the study period, data from 297,545 to 10,081,414 individuals were available annually; in 2020, 1946 individuals were diagnosed with PN. The prevalence and incidence of PN showed little variation over the study period; in 2021, the prevalence was 41 per 100,000 persons. Although there was a tendency for a higher prevalence of PN in childhood, the prevalence and incidence were similar in other age groups and were slightly higher in females. Inflammatory skin diseases and atopic diathesis were common comorbidities. The most prescribed treatments for adults with PN were topical steroids (78%), oral antihistamines (68%), and moisturizers (54%). Oral steroids, macrolides, and psychotropics were prescribed to >10% of patients. Individuals with PN who also had atopic dermatitis (AD) received higher cumulative doses of stronger potency topical steroids, local steroid injections, and oral steroids than those without concomitant AD. Additionally, HCRU was higher in individuals with AD. Conclusions: Although patients are usually treated according to the guidelines, there is an unmet need for more effective treatments for PN due to the frequent use of intensive and late-line treatments.

A comprehensive bibliometric analysis of prurigo nodularis literature (1951-2024): Key contributors, trends, and thematic evolution

This study provides a comprehensive bibliometric analysis of prurigo nodularis (PN) literature, identifying influential studies, key contributors, and emerging trends to understand the evolution of research and guide future investigations. A total of 499 contributions published between 1951 and October 2024, containing the term "prurigo nodularis" in their abstracts, were analyzed. Keyword analysis was conducted to determine the main themes across these publications. Additionally, the top 100 most cited articles on PN from 1979 to 2023 were examined, involving 51 journals. Metrics such as mean total citations per contribution (MeanTCperArt) and mean total citations per year (MeanTCperYear) were calculated for these top 100 articles. The analysis of the top 100 most cited articles revealed contributions from 453 authors. The number of publications, citations, h-index, g-index, m-index, hg composite, and Q2 index were calculated for each author. We have illustrated the dynamics of top authors, universities, and countries, as well as their respective collaboration networks. The thematic evolution of PN research was assessed using coword analysis, followed by a systematic discussion of the findings. This bibliometric analysis provides a comprehensive overview of the key contributors and research trends in PN literature, offering valuable insights for guiding future investigations.

Efficacy and Safety of Nemolizumab in Patients With Prurigo Nodularis: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

This meta-analysis evaluated the efficacy and safety of nemolizumab in treating prurigo nodularis through a systematic review of randomized controlled trials. A comprehensive literature search was conducted across multiple databases, including PubMed, Embase, Cochrane Library, and Web of Science, identifying relevant studies until January 5th 2025. Four randomized controlled trials involving 859 participants were included in the final analysis. The primary outcomes assessed were itching response measured by the Worst Itch Numeric Rating Scale (WI-NRS) and Investigator's Global Assessment (IGA) success. Nemolizumab demonstrated significant improvement in itch response compared to control, with a risk ratio of 3.52 (95% CI: 2.48 to 5.02, p < 0.00001) and low heterogeneity (I² = 28%). Similarly, IGA success rates were notably higher in the nemolizumab group, with a risk ratio of 4.40 (95% CI: 2.86 to 6.75, p < 0.00001) and low heterogeneity (I² = 11%). While adverse events were slightly more frequent in the nemolizumab group, the difference was not statistically significant (RR: 1.11, 95% CI: 0.99 to 1.24). The analysis was limited by the small number of included trials, relatively short follow-up periods, and lack of subgroup analysis. Despite these limitations, the findings suggest that nemolizumab is an effective and well-tolerated treatment for prurigo nodularis. Further research with longer follow-up periods and larger, more diverse patient populations is recommended to establish the long-term efficacy and safety profile of nemolizumab in treating this condition.

Healthcare Resource Utilization and Economic Burden of Prurigo Nodularis in the United States

INTRODUCTION

The impacts of prurigo nodularis (PN) on healthcare resource utilization (HCRU) and associated costs are unclear.

METHODS

This retrospective, cross-sectional claims analysis (IQVIA PharMetrics® Plus) compared HCRU and costs over 1 year in adults with PN versus matched controls (region, payer type, age, sex, year) from 2016 to 2019, and also in patients with PN receiving advanced versus localized/no therapy. For patients with data in multiple calendar years, 1 year was randomly selected. Outcomes were compared by chi-square tests, t tests, or negative binomial tests.

RESULTS

We matched 16,888 patients with PN with 16,888 controls. Most comorbidities (mental health, metabolic conditions, type 2 inflammatory diseases) appeared more frequently in patients with PN versus controls. HCRU was significantly (P < 0.001) higher for patients with PN versus controls, including mean (standard deviation, SD) number of outpatient visits (17.0 [15.5] vs 8.1 [10.7]) and proportion of patients with hospitalizations (9.3% vs 5.9%). Mean (SD) total costs were significantly (P < 0.001) greater for patients with PN versus controls ($18,315 [$66,476] vs $8451 [$30,982]).

CONCLUSIONS

Patients with PN receiving advanced therapy had higher HCRU and costs versus localized/no therapy. Patients with PN (particularly those receiving advanced therapies) incurred higher all-cause HCRU burden and associated costs than matched controls. Enhanced feature (slides, video, animation) (MP4 12313 KB).

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.

Two Cases of Prurigo Nodularis in Hematologic Malignancies: Hodgkin Lymphoma and Waldenström Macroglobulinemia

Prurigo nodularis (PN) is a chronic inflammatory skin disorder marked by intense itching and firm, pruritic nodules, often linked to dermatologic, autoimmune, or systemic conditions, including malignancies such as hematologic cancers. We present two cases illustrating PN as a potential cutaneous manifestation of hematologic malignancies: a 48-year-old male with a history of psoriasis and persistent pruritus misdiagnosed as scabies, later found to have Hodgkin lymphoma, and an 86-year-old female with fatigue, anemia, and erythematous lesions diagnosed with Waldenström macroglobulinemia. These cases underscore the importance of recognizing PN as a symptom of underlying malignancy, enabling earlier diagnosis and treatment to improve outcomes.

Effectiveness and Safety of Dupilumab for Prurigo Nodularis in China: A Multicentric and Observational Study

BACKGROUND

The efficacy and safety of dupilumab in patients with refractory prurigo nodularis (PN) is well established in clinical trials, but there is a lack of multicenter data regarding its effectiveness and safety in real-world settings.

METHODS

Patients with moderate-to-severe PN who initiated dupilumab treatment between July 2023 and January 2024, with a follow-up period of at least 16 weeks at 10 hospitals in China were included. We used peak pruritus numeric rating scale (PP-NRS), investigator global assessment (IGA) for PN, and dermatology life quality index for adults or children (DLQI/CDLQI) to assess disease control status and quality of life impairment, and monitored adverse events to assess the safety.

RESULTS

A total of 73 PN patients (33 female, 40 male; mean age 45.9 ± 21.5 years) were included. A clinically meaningful improvement of ≥ 4 points in PP-NRS (PP-NRS4) was achieved in 84.9% of patients at Week 12. The percentage of patients achieving IGA 0/1 significantly increasing from 0% to 37.0% and 46.6% at Week 12 and 16, respectively. Patient-reported quality of life outcomes showed substantial improvement, with decreasing from 16.6 ± 6.8 at baseline to 7.2 ± 4.9 at Week 12, 6.4 ± 4.5 at Week 16. The safety profile of dupilumab was favorable, with one patient reporting dry eyes.

CONCLUSION

Dupilumab can effectively improve the pruritus, nodular lesions and quality of life for PN in real-world settings.

Efficacy and safety of narrowband ultraviolet B phototherapy for prurigo nodularis: a tertiary center experience

BACKGROUND

Prurigo nodularis is a chronic pruritic dermatosis and narrowband-UVB (NB-UVB) phototherapy is considered an effective and safe treatment option in patients with multiple comorbidities.

OBJECTIVE

In this study, the authors aimed to evaluate the efficacy and safety of NB-UVB phototherapy in the management of prurigo nodularis and to compare response rates according to lesions localization.

METHODS

Thirty prurigo nodularis patients who had been treated with NB-UVB phototherapy were included in this study. The data for this study were retrieved retrospectively from patient follow-up forms in the phototherapy unit.

RESULTS

NB-UVB phototherapy led to a complete response (CR) in 24 (80%) patients while partial response (PR) was achieved in 6 (20%) patients. Regarding prurigo nodularis localization, the CR rate was statistically higher in those with diffuse and central involvement (p < 0.05). Erythema and/or pruritus were observed in 4 (13.3%) patients with prurigo nodularis.

STUDY LIMITATIONS

This study is limited because it is single-centered and has a retrospective design.

CONCLUSIONS

NB-UVB phototherapy is an effective and safe treatment option for prurigo nodularis patients especially those with multiple comorbidities and using several medications. Patients with diffuse and central involvement may respond better to phototherapy than those with peripheral involvement.

Elevated C-reactive protein levels and cardiovascular risk in prurigo nodularis patients with sleep disturbance: a multi-center cohort study

Patients with prurigo nodularis (PN) present with pruritus which may lead to sleep disturbances and systemic comorbidities. The objective of our study was to determine the risk of sleep disorders in PN and its association with systemic inflammation and adverse cardiovascular outcomes. We conducted a retrospective population-level cohort using a global health records database to analyze the development of sleep disorders, C-reactive protein (CRP) levels, and risk of cardiovascular disease and mortality in PN compared to controls. PN patients had increased risk of general sleep disorders (RR 1.47, 95%CI 1.42-1.52, obstructive sleep apnea (1.61, 1.54-1.69), insomnia (1.37, 1.29-1.45), hypersomnia (1.47, 1.32-1.64), and restless legs syndrome (1.45, 1.28-1.65). Additionally, PN with sleep disorders had higher CRP levels than PN without sleep disorders (16.2 mg/L vs. 10.6 mg/L). PN patients with sleep disorders were more likely to develop cardiovascular comorbidities, including type 2 diabetes mellitus (RR 2.45, 95%CI 2.25-2.66), metabolic syndrome (4.16, 3.31-5.22), myocardial infarction (2.87, 2.52-3.22), venous thromboembolism (2.93, 2.55-3.39), and greater mortality (HR 1.47, 95%CI 1.34-1.62) compared to PN patients without sleep disorders. Our findings suggest that PN patients are at greater risk of developing various sleep disorders that are associated with adverse cardiovascular outcomes.

Consensus on the Diagnostic Algorithm for Chronic Nodular Prurigo

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

[Translated article] Consensus on the Diagnostic Algorithm for Chronic Nodular Prurigo

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

Responder analysis using clinically meaningful thresholds: Post hoc analyses from randomized dupilumab clinical trials in patients with prurigo nodularis

BACKGROUND

Prurigo nodularis (PN) is an intensely pruritic disease characterized by itchy nodules on the trunk/extremities; it is often accompanied by skin pain and sleep disruption with negative impacts on the quality of life (QoL). The patient-reported outcome (PRO) instruments, Worst Itch-Numeric Rating Scale (WI-NRS), Skin Pain-NRS, Sleep-NRS and Dermatology Life Quality Index (DLQI) have been psychometrically validated and the clinically meaningful within-patient improvement thresholds (responder definition) have been established through data pooled from the two Phase-3 trials (PRIME, NCT04183335 and PRIME2, NCT04202679) of dupilumab in adults with PN uncontrolled on topical therapies.

OBJECTIVES

To estimate the proportion of dupilumab-treated patients (vs. placebo) achieving clinically meaningful improvement in itch, skin pain, sleep and QoL, either alone or in combination, from the data pooled from PRIME and PRIME2 trials.

METHODS

The patient-level data pooled from the two Phase-3 trials (N = 311) were used for this post hoc analysis. Thresholds of clinically meaningful within-patient improvement in PRO instrument scores from baseline at Week 24 used for defining responders were 4 (WI-NRS and Skin Pain-NRS), 2 (Sleep-NRS) and 9 points (DLQI). The proportion of dupilumab-treated patients, versus placebo, achieving the thresholds, and the time taken to achieve the thresholds were evaluated for the individual and combination of PROs.

RESULTS

Responder rates were significantly higher with dupilumab, versus placebo at Week 24 for WI-NRS (58.8% vs. 19.0%, p < 0.0001), Skin Pain-NRS (49.7% vs. 20.9%, p < 0.0001), Sleep-NRS (42.5% vs. 23.4%, p < 0.0001) and DLQI (64.7% vs. 22.8%, p < 0.0001). Proportion of patients achieving simultaneous improvement in symptoms and QoL (24.8% vs. 6.3%, p < 0.0001) were significantly higher in dupilumab-treated patients versus placebo. The time needed for achieving clinically meaningful improvement in symptoms were significantly lower in dupilumab-treated patients, versus placebo.

CONCLUSIONS

Significantly greater proportion of dupilumab-treated patients with PN, versus placebo, demonstrated clinically meaningful improvements in PRO measures of symptoms and QoL.

Healthcare resource utilization and related cost among hospitalized patients with prurigo nodularis: a retrospective cohort study using Italian health claims data

BACKGROUND

Prurigo nodularis (PN) is a chronic, inflammatory skin disease characterized by intense itch. Little evidence exists on the burden of PN in Italy. This real-world analysis aimed to investigate the healthcare resource consumption and related direct costs of patients hospitalized for PN.

METHODS

The analysis utilized the administrative databases of healthcare units that cover approximately 12 million inhabitants across Italy. Adult patients were included by ICD-9-CM=698.3 (lichen simplex chronicus; neurodermatitis circumscripta; PN) as proxy of PN diagnosis, from 01/2010 to 09/2021, and had 1 year of data availability before (baseline) and after (follow-up) hospitalization (index date). These patients were 1:2 matched by age, sex, and index date (year) to adults without such hospitalization in the baseline period (matched non-PN controls).

RESULTS

The analysis comprised 295 PN-hospitalized patients, matched with 590 non-PN individuals (mean age 63.2 years, 43.7% female). At baseline, patients had a greater comorbidity burden than non-PN controls, including higher prevalence of hypertension (56.6% vs. 36.6%, respectively), dyslipidemia (26.4% vs. 18.0%), diabetes (24.4% vs. 12.5%) and mental health conditions (14.9% vs. 7.8%). During 1-year follow-up, PN-hospitalized patients had significantly higher resource consumption than matched controls, in terms of mean number of prescriptions most commonly prescribed in PN patients (5.1 vs. 1.9, P<0.001), other drugs (11.7 vs. 6.5, P<0.001), all-cause hospitalization (1.4 vs. 0.1, P<0.001) and outpatient services (5.4 vs. 2.5, P<0.001). Mean annual all-cause healthcare costs for patients over 1-year follow-up were € 3847 total (€ 875 drugs, € 2652 hospitalization, € 320 outpatient services), higher than those for the matched controls, of € 711 total (P<0.001) (€ 353 drugs, € 228 hospitalization, € 130 outpatient services).

CONCLUSIONS

Patients hospitalized for PN had a higher comorbidity burden at baseline and greater healthcare resource consumption during 1-year follow-up compared to matched controls, with a 5.4-fold increase in all-cause healthcare costs, indicating substantial clinical burden and remaining unmet need in these patients.

Treatment With Upadacitinib in Refractory Prurigo Nodularis: A Prospective Cohort Study

Prurigo nodularis (PN) is a chronic neuroinflammatory dermatosis with severe pruritus that has limited efficacy in various conventional treatments. This study investigated the outcomes of upadacitinib treatment in patients with refractory PN. A prospective study was conducted to screen for potential chronic infections prior to treatment. Upadacitinib was administered at a daily dose of 15 mg for 24 weeks, and the treatment response was assessed using the itch Numeric Rating Scale (NRS), investigator's Global Assessment (IGA), and Dermatology Life Quality Index (DLQI). Adverse events were monitored at each visit. Ten patients, with an average age of 48.8 years, were included in the study. All participants were treated with systemic cyclosporine before receiving upadacitinib, which yielded limited responses. At baseline, the mean prurigo severity scores assessed using the IGA, DLQI, and itch NRS were 3.4, 17.8, and 8.1, respectively; after 24 weeks of treatment, these scores significantly reduced to 1.0, 0.6, and 0.8, respectively. No severe adverse effects were observed. In conclusion, upadacitinib could be considered an alternative therapeutic option with good tolerability for refractory PN.

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.

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

Importance

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

Objective

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

Design, Setting, and Participants

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

Intervention

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

Main Outcomes and Measures

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

Results

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

Conclusions and Relevance

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

Trial Registration

ClinicalTrials.gov Identifier: NCT05038982.

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.

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.

Ex Vivo Confocal Laser Scanning Microscopy in Rare Skin Diseases

While ex vivo confocal laser scanning microscopy has previously demonstrated its utility in most common skin diseases, its use in the assessment of dermatological entities with lower incidence remains unexplored in most cases. We therefore aimed to evaluate the diagnostic efficacy of some rare skin tumors as well as a few inflammatory skin diseases, that have not yet been studied in ex vivo confocal laser scanning microscopy. A total of 50 tissue samples comprising 10 healthy controls, 10 basal cell carcinoma, 10 squamous cell carcinoma, and 20 rare skin conditions were imaged using the newest generation ex vivo confocal microscopy (Vivascope 2500 M-G4, Vivascope GmbH, Munich, Germany). Three blinded investigators were asked to identify characteristic features of rare skin disorders and distinguish them from more common skin diseases in the ex vivo confocal microscopy images. Our findings present the capability of ex vivo confocal microscopy to display distinctive morphologic patterns in common and rare skin diseases. As might be expected, we found a strong correlation between imaging experience and diagnostic accuracy. While the imaging inexperienced dermatohistopathologist reached 60% concordance, the imaging-trained dermatologist obtained 88% agreement with dermatohistopathology. The imaging-trained dermatohistopathologist achieved concordance up to 92% with gold-standard dermatohistopathology. This study highlights the potential of ex vivo confocal laser scanning microscopy as a promising adjunct to conventional dermatohistopathology for the early and precise identification of rare dermatological disorders.

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

BACKGROUND

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

METHODS

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

FINDINGS

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

INTERPRETATION

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

FUNDING

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

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

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

A systematic review of interleukin-31 inhibitors in the treatment of prurigo nodularis

BACKGROUND

Prurigo nodularis (PN) is a neuroimmunological skin disease. Severe itching is the most challenging symptom which affects patients' quality of life. T helper 2-derived cytokines, such as interleukin-31 and oncostatin M (OSM), play a crucial role in PN pathogenesis. Nemolizumab and vixarelimab are two biologics acting as IL-31 inhibitors. Vixarelimab also suppresses the OSM activity. This systematic review evaluates the efficacy and safety of nemolizumab and vixarelimab in PN management.

METHODS

A systematic search was conducted in PubMed/Medline, Ovid Embase, and Web of Science up to September 17th, 2023. Clinical trials and cohort studies published in English were included.

RESULTS

Among a total of 96 relevant records, five were included. The results of four studies with 452 patients using nemolizumab showed that a significantly higher percentage of patients treated with nemolizumab demonstrated a reduction in peak pruritus numerical rating scale (PP-NRS) and investigator's global assessment along with improved sleep disturbance (SD) and quality of life than the placebo group. Moreover, one study administered vixarelimab to 49 PN patients, and their finding illustrated a higher rate of subjects who received vixarelimab experienced ≥ 4-point diminution in worst itch NRS, visual analog scale, healing of representative lesions, and SD quality compared to the placebo group.

CONCLUSIONS

IL-31 inhibitors suggest distinct advantages in improving pruritus, sleep quality, and overall quality of life in subjects with moderate-to-severe PN. Further clinical studies are recommended to compare the effectiveness of these biologics to other therapeutic choices.

Evaluation of the histopathological spectrum of skin biopsies in patients with chronic kidney disease: A single-center experience

BACKGROUND AND AIM

Patients with chronic kidney disease (CKD), particularly those with end-stage renal disease (ESRD), frequently experience skin problems. Here, we present and discuss the histopathology results of skin biopsies performed on renal patients at our facility.

MATERIALS AND METHODS

We retrospectively reviewed all histopathological reports and slides of skin biopsies taken from CKD patients for the last 5 years at the Pathology Department of King Saud University Medical City, King Saud University in Riyadh.

DESIGN

This is a retrospective cross-sectional study.

RESULTS

Patients were 19 (43.2%) males and 25 (56.8%) females, with a mean age of 53.4 19.8 years. Diabetic nephropathy, hypertensive nephropathy, and lupus nephritis were the three most common kidney pathologies (59.1%, 11.4%, and 11.4%, respectively). Seventeen patients (38.5%) were receiving hemodialysis. Acquired perforating collagenosis (APC), which was observed in 16 (36.4%) of our patients, was the most prevalent skin pathology, followed by bullous drug reactions in nine (20.5%), leukocytoclastic vasculitis (LCV) in eight (18.2%), calciphylaxis in six (13.6%), and prurigo nodularis in five (11.4%) patients. Erythematous plaques and papules were the most prevalent skin conditions at the time of presentation in 12 patients (27.3%), followed by pruritus in six (13.6%) and ulcerations in six (13.6%) patients. Collected data were analyzed using the Statistical Package for Social Sciences (SPSS) version 26.0.

CONCLUSION

A spectrum of skin conditions may be seen in CKD patients. The quality of life of CKD patients will be significantly improved by identifying and managing these conditions. Pathologists' familiarity with this spectrum is important, as a correct histopathologic diagnosis will lead to a better outcome.

A critical review of dupilumab for adult patients with prurigo nodularis

INTRODUCTION

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

AREAS COVERED

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

EXPERT OPINION

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

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

BACKGROUND

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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

Abstract is missing (Short communication)

Systemic Complications of Primary Biliary Cholangitis

Chronic cholestasis is the hallmark clinical feature of primary biliary cholangitis. In addition to progressive liver damage, chronic cholestasis can lead to serious complications, many of which occur outside the liver. Bile acids are ligands for nuclear hormone receptors, and alterations in their concentration disrupt normal functioning of numerous different cell types. This article discusses the clinical presentation, pathophysiology, and management of pruritus (itching), fatigue, osteoporosis, hyperlipidemia, fat-soluble vitamin deficiencies, malignancies, cardiac dysfunction, bacterial cholangitis, cholemic (bile cast) nephropathy, and Sicca syndrome.

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

BACKGROUND

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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

BACKGROUND

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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.

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

BACKGROUND

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

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.