Prurigo Nodularis Mechanisms and Current Management Options.

Prurigo nodularis (PN) manifests with highly pruritic lesions that negatively impact patient quality of life. Due to the variability in manifestation, hypertrophic lichen planus, pemphigoid nodularis, and neurotic excoriations tend to mimic PN. The pathophysiology of PN is believed to be due to interactions in the neural and immune pathways causing the release of proinflammatory and pruritogenic cytokines. Dermatologic and systemic conditions, including atopic dermatitis and chronic kidney disease, accompany PN diagnoses. Patients with moderate to severe or recalcitrant PN may benefit from dupilumab, the first medication approved by the US Food and Drug Administration (FDA) to treat PN. Here, we provide an updated review of PN with a focus on its pathophysiology, histologic findings, and current treatment options.

[Prurigo pigmentosa: Case report of a German adolescent]. / Prurigo pigmentosa: Fallbericht eines deutschen Jugendlichen.

Prurigo pigmentosa is an inflammatory dermatosis that rarely occurs in Europe and mostly affects young women. Here, we describe the typical clinical and dermoscopic criteria so that therapy can be initiated as early as possible. The 17-year-old patient presented here shows that this disease can also be observed in Western Europe and in men, and that doxycycline is a very effective treatment option.

Worst Itch Numeric Rating Scale for Prurigo Nodularis: A Secondary Analysis of 2 Randomized Clinical Trials.

Importance: Prurigo nodularis (PN) is a debilitating skin disease characterized by the hallmark symptom of chronic itch; the intensity of itch in PN was assessed using the Worst Itch Numeric Rating Scale (WI-NRS) to evaluate the primary efficacy end point of 2 recent phase 3 studies of dupilumab treatment for PN. Objective: To validate the psychometric properties and to determine the clinically meaningful improvement threshold for WI-NRS in patients with moderate to severe PN. Design, Setting, and Participants: In this secondary analysis of the PRIME and PRIME2 trials, content validity of WI-NRS was assessed through in-depth patient interviews. Psychometric assessments used pooled data from masked, intention-to-treat (ITT) patients with PN from randomized, double-masked, and placebo-controlled studies. Psychometric assessments included test-retest reliability, construct validity, known-groups validity, and sensitivity to change in adult patients with moderate-to-severe PN. Thresholds for meaningful within-patient improvement in the WI-NRS score were determined using anchor and distribution-based approaches. Data were analyzed after completion of each study, December 2019 to November 2021 for PRIME and January 2020 to August 2021 for PRIME2. Exposures: Dupilumab (300 mg) or placebo subcutaneously every 2 weeks for 24 weeks. Main outcomes and measures: WI-NRS score at specified time points up to 24 weeks after randomization. Results: A total of 20 patients were included across the 2 studies (mean [SD] age, 49.3 [17.2] years; 11 female [55%]); 311 patients were included in the pooled intention-to-treat analysis (mean [SD] age, 49.5 [16.1] years; 203 female [65.3%]). The WI-NRS questions (20 of 20 patients), recall period (19 of 20 patients), and response scale (20 of 20 patients) were easy to understand and relevant for patients with PN. Adequate test-retest reliability was observed between screening and baseline (intraclass correlation coefficient = 0.72, using Patient Global Impression of Severity [PGIS] to define stable patients). Convergent and discriminant validity was supported by moderate to strong correlations (absolute r range = 0.34-0.73) with other conceptually related measures and weaker correlations (absolute r range = 0.06-0.32) with less-related measures, respectively. WI-NRS was sensitive to change, as demonstrated by differences in change from baseline among groups (per PGIS change and PGI of Change [PGIC]). Using anchor-based approach with PGIS and PGIC, the clinically meaningful improvement threshold was 4 points (range, 3.0-4.5), which was also supported by distribution-based methods. Conclusion and Relevance: This study found that WI-NRS may be a fit-for-purpose instrument to support efficacy end points measuring the intensity of itching in adults with PN. Trial Registration: NCT04183335 (PRIME) and NCT04202679 (PRIME2).

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.

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 ß-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.

Deciphering the enigma of itch sensation: insights and impact from a readability study.

BACKGROUND: Itch terminology is ambiguous. How itch was described in online materials and how terminology influenced the readability of these materials was previously unknown. MATERIALS AND METHODS: Two groups of search terms, itch and prurigo, were translated into five of the most prevalent European Union (EU) languages. The itch group consisted of "itch" and "pruritus." The prurigo group consisted of "prurigo," "prurigo nodularis," and "chronic prurigo". Then, a search of the terms in each language was queried in the Google search engine in the private mode of the Internet browser. The first 50 results generated were assessed for suitability. Patient education was the primary objective of the materials provided, with no barriers or advertisements included. In cases where the terms yielded identical outcomes, any duplicated materials were omitted from the analysis. When translating search terms within a group led to just one shared transcription, the results were attributed to the search term with the most similar syntax. The Lix score was utilized to assess readability. RESULTS: 314 articles in English, German, Italian, French, and Spanish were evaluated. The term "pruritus" was the most commonly used description for the sensation of itching, with 142 (45%) articles included. Overall, the mean Lix score was 54 ± 9, classifying all articles as hard to comprehend. Articles in the itch group had significantly (P < 0.001) lower mean Lix score (52 ± 9) than materials in the prurigo group (56 ± 10). CONCLUSIONS: Despite being more accessible to conceptualize, skin conditions such as prurigo had lower readability compared to information about the itch itself. The distinction between "itch" and "pruritus" was unclear.

Prurigo: review of its pathogenesis, diagnosis, and treatment.

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

A case of bullous pemphigoid following administration of anti-IL-31 receptor A antibody.

Bullous pemphigoid (BP), an autoimmune bullous dermatosis, occurs predominantly in older individuals. Nemolizumab, a humanized monoclonal antibody against the interleukin (IL)-31 receptor A, is used to treat severe atopic dermatitis (AD) in Japan. However, it can cause several adverse events, such as exacerbation of AD, erythema, and eosinophilia. Herein, we describe a case of prurigo-type AD developing BP after nemolizumab administration. A 62-year-old man with prurigo-type AD and asthma presented with serious, refractory itching. After nemolizumab injection, his pruritus was relieved for 2 days. However, on day 3, erythema with blisters and erosions suddenly appeared throughout his body. Pathological examination showed typical BP and the patient's serum anti-BP180-NC16a antibody level was 882.5 U/mL. Oral prednisolone (PSL) was initiated and nemolizumab was never used again. Despite high-dose PSL, new blisters continued to develop, with a rapid elevation of anti-BP180-NC16a antibodies to 6930 U/mL. Adding high-dose cyclosporine and intravenous gamma globulin reduced new blister formation after 9 weeks, and PSL and cyclosporine were gradually tapered. Dupilumab, an anti-IL-4 receptor antibody, was initiated after 16 weeks, resulting in continued remission without PSL and cyclosporine. The sudden occurrence of BP in this case suggested that the patient had occult BP before the nemolizumab initiation and that nemolizumab exacerbated BP and made it overt. Blocking the IL-31 pathway may exacerbate inflammation in AD or BP, resulting in the acceleration of blister formation. This may be countered by blocking the IL-4/13 pathway with dupilumab. To our knowledge, this is the first case of nemolizumab-exacerbated BP.

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.

Development and Validation of a Patient-Reported Outcome Measure to Assess Disease Control in Chronic Prurigo.

Importance: Chronic prurigo (CPG), including prurigo nodularis, is a difficult disease to treat and considerably affects patients' quality of life. Helping patients obtain control of CPG is a major treatment goal. Objective: To develop and validate the Prurigo Control Test (PCT), a tool for assessing disease control in CPG, and to identify a cutoff value for controlled disease to aid treatment decisions. Design, Setting, and Participants: This qualitative study followed the current recommendations for patient-reported outcome measure development in the generation and validation of the PCT. The final PCT was obtained after item generation, followed by reduction and selection, and was then tested for internal consistency and test-retest reliability, convergent validity, known-group validity, screening accuracy, and banding. The item-generation phase resulted in an unselected list of 69 potential PCT items. Impact analysis, interitem correlation, and review for content (face) validity resulted in final set of 5 PCT items. The validation study was performed among patients across 2 expert centers in Germany. Data were analyzed from February 2017 to November 2019. Main Outcomes and Measures: A 5-item PCT with a recall period of 2 weeks was developed. A cutoff value of 10 points or higher was determined as suitable for identifying patients with well-controlled vs poorly controlled CPG. Results: Of the 95 patients included in the validation study, the median (range) age was 63 (19-87) years, 50 patients (53%) were women, and the median (range) disease duration was 72 (9-774) months. The validation study yielded good internal consistency reliability (Cronbach α, 0.86) and a high degree of convergent validity. The PCT demonstrated good known-group validity and could discriminate between patients who differed in prurigo control. Test-retest reliability was high, and the intraclass correlation coefficient was 0.94, indicating excellent reproducibility. Conclusions and Relevance: This qualitative study showed that the PCT is able to assess disease control in patients with CPG. Its retrospective approach, brevity, and simple scoring likely make the PCT suitable for clinical practice and trials.

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.

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.

Molecular mechanisms of pruritus in prurigo nodularis.

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