Position Statement: Linear prurigo is a subtype of chronic prurigo

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.

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.

Chronic Nodular Prurigo: An Update on the Pathogenesis and Treatment

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

Autoreactive Peripheral Blood T Helper Cell Responses in Bullous Pemphigoid and Elderly Patients With Pruritic Disorders

Bullous pemphigoid (BP) is a prototypic autoimmune disorder of the elderly, characterized by serum IgG autoantibodies, namely anti-BP180 and anti-BP230, directed against components of the basal membrane zone that lead to sub-epidermal loss of adhesion. Pruritus may be indicative of a pre-clinical stage of BP, since a subset of these patients shows serum IgG autoantibodies against BP230 and/or BP180 while chronic pruritus is increasingly common in the elderly population and is associated with a variety of dermatoses. Clinical and experimental evidence further suggests that pruritus of the elderly may be linked to autoimmunity with loss of self-tolerance against cutaneous autoantigens. Thus, the objective of this study was to determine autoreactive T cell responses against BP180 in elderly patients in comparison to patients with BP. A total of 22 elderly patients with pruritic disorders, 34 patients with bullous or non-bullous BP and 34 age-matched healthy controls were included in this study. The level of anti-BP180 and anti-BP230 IgG serum autoantibodies, Bullous Pemphigoid Disease Area Index (BPDAI), and pruritus severity were assessed for all patients and controls. For characterization of the autoreactive T cell response, peripheral blood mononuclear cells were stimulated ex vivo with recombinant BP180 proteins (NH2- and COOH-terminal domains) and the frequencies of BP180-specific T cells producing interferon-γ, interleukin (IL)-5 or IL-17 were subsequently determined by ELISpot assay. Patients with BP showed a mixed Th1/Th2 response against BP180 while autoreactive Th1 cells were identified in a minor subset of elderly patients with pruritic disorders. Furthermore, our T cell characterization revealed that therapeutic application of topical clobetasol propionate ointment in BP patients significantly reduced peripheral blood BP180-specific T cells, along with clinically improved symptoms, strongly suggesting a systemic immunosuppressive effect of this treatment.

Chronic nodular prurigo: clinical profile and burden. A European cross-sectional study

BACKGROUND

Chronic nodular prurigo (CNPG) is a condition characterized by chronic itch, a prolonged scratching behaviour and the presence of pruriginous nodules. A comprehensive understanding of this condition, especially regarding its clinical characteristics and impact on quality of life is still lacking.

OBJECTIVES

Aim of this pan-European multicentre cross-sectional study was to establish the clinical profile of CNPG, including its associated burden.

METHODS

Fifteen centres from 12 European countries recruited CNPG patients presenting at the centre or using the centres' own databases. Patients were asked to complete a questionnaire in paper or electronic format. Demography, current co-morbidities, underlying disease, itch intensity, additional sensory symptoms, quality of life, highest burden and emotional experience of itch were assessed.

RESULTS

A total of 509 patients (210 male, median age: 64 years [52; 72]) were enrolled. Of these, 406 reported itch and CNPG lesions in the previous 7 days and qualified to complete the whole questionnaire. We recorded moderate to severe worst itch intensity scores in the previous 24 h. Scores were higher in patients with lower educational levels and those coming from Eastern or Southern Europe. Most patients experience itch often or always (71%) and report that their everyday life is negatively affected (53%). Itch intensity was considered to be the most burdensome aspect of the disease by 49% of the patients, followed by the visibility of skin lesions (21%) and bleeding of lesions (21%). The majority of patients was unaware of an underlying condition contributing to CNPG (64%), while psychiatric diseases were the conditions most often mentioned in association with CNPG (19%).

CONCLUSIONS

This multicentre cross-sectional study shows that itch is the dominant symptom in CNPG and reveals that the profile of the disease is similar throughout Europe.

Is there still a role for UV therapy in itch treatment?

Itching is a frequent and greatly distressing symptom related to many skin and systemic diseases. New insights into the pathophysiology of itchy skin and potentially involved mediators have increased the interest in and development of new treatments that specifically act on targets involved in the transmission and perception of itching. Phototherapy has long been known and used as an effective treatment for various kinds of chronic itching. However, despite its well-known beneficial effects, the mechanisms behind the antipruritic effect of phototherapy are less well-known. In addition, phototherapy requires the use of expensive equipment in dermatology offices, patients must undergo repeated treatments and no large, randomized, controlled trials have yet supported the antipruritic effect of UV. Therefore, phototherapy is rarely recommended as a treatment method for chronic pruritic diseases or only used as a last recourse. However, the wide range of pruritic conditions that can be successfully treated with phototherapy, together with its low acute side effects, extremely low frequency of interactions with other medications, possibilities to combine phototherapy with other treatment modalities and the fact that patients of almost all ages-from childhood to old age, including women during pregnancy or lactation-can be treated make UV therapy advantageous over other treatments of chronic pruritus. Thus, despite the development of new targeted therapies against pruritus, UV therapy is neither outdated nor the 'last recourse', but should be considered early on in the treatment of chronic pruritus.