An update on genetic basis of generalized pustular psoriasis (Review)

Update on Generalized Pustular Psoriasis

Generalized pustular psoriasis (GPP) is a rare but severe inflammatory skin disease characterized by the eruption of widespread sterile pustules, often accompanied by systemic inflammation. Although GPP can coexist with plaque psoriasis, it is increasingly recognized as a distinct entity with unique clinicopathological, immunologic, and genetic features. The dysregulated IL-36 pathway, including mutations in the IL36RN gene, is implicated in GPP pathogenesis, providing a molecular basis for targeted therapies. Diagnosing GPP requires a comprehensive evaluation, including clinical presentation, potential triggers, patient history, histopathologic findings, and laboratory results. Disease severity must be assessed through both cutaneous symptoms and systemic involvement, as GPP flares can lead to life-threatening complications such as sepsis and multi-organ failure. Historically, GPP treatment primarily relied on therapies approved for plaque psoriasis, despite their limited specificity for this condition. Recent advances in understanding the molecular mechanisms of GPP, particularly the central role of interleukin-36 pathway, have led to the development of targeted therapies for this rare condition. Currently, spesolimab is the only therapy specifically approved for treating GPP flares in adolescents and adults, in both Europe and the United States of America. However, the management of GPP remains complex and challenging. This narrative review provides an overview of the epidemiology, pathophysiology, clinical features, comorbidities, and evolving therapeutic strategies for GPP.

Epidemiology of generalized pustular psoriasis in Germany: Analyzing factors influencing prevalence estimates health insurance data

BACKGROUND AND OBJECTIVES

Generalized pustular psoriasis (GPP) is a rare, chronic, potentially life-threatening skin disease. We aimed to establish criteria to accurately approximate GPP prevalence in Germany.

METHODS

A retrospective analysis of the WIG2 health claims database (1/1/2016-31/12/2020) was conducted. Patients aged ≥ 12 years continuously enrolled in their statutory health insurance with one inpatient or confirmed outpatient diagnosis code for GPP (International Classification of Diseases, 10th Revision [ICD-10] L40.1) were included. Scenarios with increasingly strict criteria were used to identify the GPP population.

RESULTS

From 2016-2020, 5,236 potential GPP cases were identified based on a recorded GPP diagnosis. The scenario of ≥ 1 GPP diagnosis yielded the highest prevalence (336-390 patients/million) followed by > 1 GPP diagnosis in ≥ 2 quarters (189-288 patients/million); scenarios resulting in the lowest prevalence were diagnosis in ≥ 2 quarters AND two independent diagnoses (17-28/million) and diagnosis in ≥ 2 quarters AND two independent diagnoses or diagnosis by a specialist AND potential flare (58-61 patients/million).

CONCLUSIONS

This study suggests that diagnosis in ≥ 2 quarters by a specialist or two independent physicians may be the most clinically robust and reliable criteria for estimating GPP prevalence; therefore, 50-100 patients/million may represent a reasonable prevalence estimate range for Germany.

Considerations for defining and diagnosing generalized pustular psoriasis

Generalized pustular psoriasis (GPP) is a rare, chronic skin disease, characterized by widespread pustules and erythema, often accompanied with systemic signs and symptoms. GPP flares occur episodically but may be protracted. Left untreated, GPP can be life-threatening. Despite being first reported over 100 years ago, definitions and diagnostic criteria for GPP have been inconsistent and varied due, in part, to its rarity and a limited understanding of its pathogenesis. As such, many patients with GPP face delays in diagnosis and subsequent treatment. This manuscript aims to increase the recognition of GPP and provide foundational considerations to aid in the definition and diagnosis of this disease.

Spesolimab Reduces Inflammation in Generalized Pustular Psoriasis: Molecular Characterization of Flare Treatment in EFFISAYIL 1

EFFISAYIL 1 was a randomized, placebo-controlled study of spesolimab, an anti-IL-36 receptor antibody, in patients presenting with a generalized pustular psoriasis flare. Treatment with spesolimab led to more rapid pustular and skin clearance versus treatment with placebo in approximately half of the patients. In this study, we present histologic, transcriptomic, and proteomic analyses of lesional and nonlesional skin and whole-blood samples collected from EFFISAYIL 1. Treatment with spesolimab led to a transition toward a nonlesional profile, with a downregulation of gene expressions in the skin of IL-36 transcripts (IL36α, IL36β, IL36γ) and those associated with neutrophil recruitment (CXCL1, CXCL6, CXCL8), proinflammatory cytokines (IL6, IL19, IL20), and skin inflammation (DEFB4A, S100A7, S100A8). Changes were manifest at week 1 and sustained to week 8. At the systemic level, reductions in serum biomarkers of inflammation (IL-17, IL-8, IL-6) were sustained until 12 weeks after spesolimab treatment. Considerable overlap was observed in the spesolimab-induced changes in gene and protein expressions from skin and blood samples, demonstrating the molecular basis of the effects of spesolimab on controlling local and systemic inflammation. Data are consistent with the mode of action of spesolimab, whereby inhibition of the IL-36 pathway leads to subsequent reductions in the key local and systemic pathologic events associated with generalized pustular psoriasis flares.

Dissolving microneedle synergistic rocaglamide-loaded liposome to regulate abnormal neutrophils for anti-psoriasis

Psoriasis seriously affects the physical and mental health of patients. Rocaglamide (RocA), derived from Aglaia odorata, exhibits potent pharmacological activities. Although its efficacy in psoriasis is unclear, RocA could be a promising therapeutic drug. In this work, RocA showed a good therapeutic effect in psoriasis mice induced by imiquimod, and subsequent TMT-based proteomics analysis verified that the effect of RocA was related to IL-1 family cytokines. Furthermore, a RocA-loaded liposome (RocA@Lipo) was developed and encapsulated in the tip-layer of microneedles (MNs) to construct a MN-based nano drug delivery system (RocA@Lipo-MNs). In vitro HaCaT cell assays demonstrated that RocA@Lipo enhanced the cytotoxicity and cell uptake of RocA. In vivo, RocA@Lipo-MNs outperformed other RocA formulations in inhibiting psoriasis epidermal thickening and spleen enlargement. Immunohistochemical, ELISA, western blot, and PCR experiments further proved that RocA@Lipo-MNs could inhibit neutrophil infiltration in the skin, revealing that the anti-psoriasis mechanism of RocA was deemed to inhibit the binding of IL-1α and IL-1R1 to regulate the activation of MAPK and NF-κB pathways. Thus, the production of inflammatory factors and neutrophil chemokines was reduced, which was associated with apoptosis inhibition. Importantly, RocA@Lipo-MNs significantly improved the transdermal properties of RocA and exhibited good skin and blood safety. This work provides new ideas for the clinical application of RocA and the treatment options for psoriasis.

Real-Life Analysis of Therapeutic Management and Its Correlation with the Dermatology Life Quality Index Score in 108 Patients with Pustular Psoriasis: An Italian Monocenter Study

INTRODUCTION

Pustular psoriasis (PP) is a rare life-threatening skin disease with negatively impact on quality of life (QoL). Clinically, it may be systemic (generalized pustular psoriasis [GPP]) or localized on palms and soles (palmoplantar pustulosis [PPP]). It is not rare to observe plaque psoriasis associated with GPP.

OBJECTIVES

We explored the therapies used for PP and their correlation with patient QoL scores, through a cross-sectional study using retrospective data from a monocentric database in the period 2017-2021.

METHODS

Patient characteristics were summarized using descriptive statistics and treatment predictors of QoL were identified by multiple regression analysis. Among 108 patients with PP, 57.4% had GPP + PSO whereas 42.6% had PPP. The therapeutic management is based on systemic conventional treatments and biological therapies in both GPP and PPP.

RESULTS

GPP + PSO patients with an impaired QoL (DLQI≥10) were associated with biological therapy including certolizumab (odds ratio [OR]=2.38), etanercept (OR=2.25), secukinumab (OR=2.03) or ustekinumab (OR=2.79) whereas, PPP patients were positively associated with secukinumab (OR=2.85) or apremilast (OR 4.28, 95%-CI 0.56-9.62).

CONCLUSIONS

Currently, systemic conventional therapy remains the therapeutic fulcrum of PP management. A great effect on QoL, especially for GPP+PSO, was assessed regardless the ongoing treatment and only newer biologic options were able to somehow positively impact.

Biologics for generalized pustular psoriasis: a systematic review and single-arm meta-analysis

Introduction

Generalized pustular psoriasis (GPP) is a rare and potentially life-threatening auto-inflammatory disease. Currently, there are no consensus-based guidelines or universally accepted treatments. Biologics represent a potential therapeutic option. This study systematically assessed the efficacy and safety of biologics in GPP.

Methods

Relevant studies from three databases were systematically searched until June 28, 2024. Statistical information, including the single-arm proportion rate of the outcomes and 95% confidence intervals (CIs), was analyzed to determine treatment effects. Heterogeneity was assessed using I² values, and subgroup analyses were performed based on drug targets and treatment durations. Data were quantitatively synthesized using a random-effects meta-analysis. Analyses were performed using R statistical software version 4.4.0.

Results

A total of 329 patients from 16 studies were included. The proportion of responders treated with IL-36 inhibitors and IL-17 inhibitors is higher than those treated with TNF-α inhibitors and IL-23 inhibitors. IL-36 inhibitors appear to achieve the highest response rates between 4 and 8 weeks, while IL-17 inhibitors, TNF-alpha inhibitors, and IL-23 inhibitors show a gradual increase in response rates up to 12 weeks. IL-36 inhibitors achieve a 40% (95% CI: 27%-54%) GPPASI75 response rate and a 55% (95% CI: 41%-68%) GPPGA (0,1) response rate within 2 weeks, significantly outperforming other biologics. The recurrence rates of GPP within 52 weeks, ranked from highest to lowest, are: IL-36 inhibitors (21% [95% CI: 9%-28%]), TNF-alpha inhibitors (20% [95% CI: 2%-46%]), IL-17 inhibitors (15% [95% CI: 1%-37%]), and IL-23 inhibitors (5% [95% CI: 0%-29%]). Additionally, 6% (95% CI: 1%-11%) of patients experienced severe adverse events.

Discussion

This meta-analysis highlights the efficacy and safety of biologics in patients with GPP, offering valuable evidence to guide future clinical practice. IL-36 inhibitors show a faster and more substantial clinical response in GPP compared to other biologics. Further research is necessary to assess their role in specific subpopulations and to evaluate their potential long-term effects on flare prevention.

Comparative Efficacy and Safety of Ustekinumab and Secukinumab in the Treatment of Generalized Pustular Psoriasis: A 48-Week Retrospective Cohort Study with Genetic Background Analysis

Purpose

Recent studies have shown that novel biologics may provide significant clinical benefits for patients with generalized pustular psoriasis (GPP). Ustekinumab and secukinumab have been approved in Japan for GPP treatment in adult patients. However, the differences in efficacy and safety of these two drugs in GPP are not known.

Aim

Based on the genetic background, we aimed to compare the efficacy and safety of secukinumab and ustekinumab in patients with GPP.

Methods

Patients with moderate to severe GPP who were treated with ustekinumab/secukinumab at our department from July 2019 to May 2022 were included in this study and followed up for 48 weeks. The difference in efficacy between ustekinumab and secukinumab was evaluated by assessing changes in body temperature, laboratory indices, recovery of skin lesions, and changes in quality of life. Additionally, we collected patients' saliva for genotyping and explored the effect of CARD14 genetic mutations on clinical efficacy.

Results

A total of 65 patients (32 adults and 33 children) with moderate to severe GPP were included in this study. 31 patients received ustekinumab therapy, and 34 patients were treated with secukinumab. Secukinumab demonstrated superiority to ustekinumab, as evidenced by a higher GPPASI 90 response at week 2. Additionally, the efficacy of ustekinumab and secukinumab was found to be independent of the presence of the CARD14 mutation.

Conclusion

Secukinumab is superior to ustekinumab in rapidly clearing the skin and improving health-related quality of life. Moreover, the responses to ustekinumab/secukinumab in patients were not influenced by CARD14 gene mutations.

Promising strategies in natural products treatments of psoriasis-update

Psoriasis is a chronic, relapsing, inflammatory skin disease and has been increasing year by year. It is linked to other serious illnesses, such as psoriatic arthritis, cardiometabolic syndrome, and depression, resulting in a notable decrease in the quality of life for patients. Existing therapies merely alleviate symptoms, rather than providing a cure. An in-depth under-standing of the pathogenesis of psoriasis is helpful to discover new therapeutic targets and develop effective novel therapeutic agents, so it has important clinical significance. This article reviews the new progress in the study of pathogenesis and natural products of psoriasis in recent years. These natural products were summarized, mainly classified as terpenoids, polyphenols and alkaloids. However, the translation of experimental results to the clinic takes a long way to go.

Clinical Characteristics and Disease Burden of Patients with Moderate-to-Severe Generalized Pustular Psoriasis Flares in Taiwan

INTRODUCTION

Generalized pustular psoriasis (GPP) is a rare and severe psoriasis subtype characterized by the rapid onset of coalescing sterile pustules over broad body areas and systemic inflammation. Data on its clinical course and outcomes in Taiwan are limited. We evaluated the clinical profile and outcomes of patients with GPP flares in Taiwan.

METHODS

This retrospective analysis included adult patients with moderate-to-severe GPP flares occurring in January 2008-December 2021. Data were extracted from medical charts and electronic health records in the Chang Gung Research Database. Statistical analyses were performed using SAS for Windows (version 9.4). Multivariate Poisson regression models were built to investigate different predictors of GPP flare rate.

RESULTS

Thirty-four patients with 81 moderate-to-severe GPP flares were identified. Of the 14 patients undergoing genetic analysis, 10 (71.4%) had an IL36RN mutation. Patients' mean age at the index GPP flare was 47.1 ± 16.5 years; 58.0% of the flares were severe, while 42.0% were moderate. Overall, 96.3% of GPP flares were treated with at least one systemic therapy, acitretin being the most prescribed (85.2%), followed by cyclosporine (45.7%) and methotrexate (18.5%). After treatment, the proportion of flares responding positively increased from 0% on day 2 to 6.2% by week 12. Patients were newly diagnosed with psoriasis (23.5%), hypertension (20.6%), diabetes mellitus (14.7%), psoriatic arthritis (2.9%), malignant tumor (8.8%), and depression/anxiety (2.9%) after enrollment. Complications occurring within 12 weeks of GPP flares included arthritis (25.9% of the flares), skin infection (8.6%), and other infections (2.5%). No fatalities were reported. In the multivariate model, former smokers, patients with hepatic disease, and patients with psoriatic arthritis had an increased GPP rate ratio (RR) of 13.33 (95% confidence interval, CI, 2.87-61.78), 14.08 (95% CI 3.04-65.29), and 34.84 (95% CI 4.77- 254.42), respectively. Contrarily, obese and rheumatoid arthritis patients had a lower GPP rate ratio of 0.21 (95% CI 0.08-0.54) and 0.07 (95% CI 0.006-0.78), respectively.

CONCLUSIONS

Our findings highlight the complexity of GPP flare presentations and the need for individualized, patient-centered management approaches and continued research to improve affected individuals' care and outcomes.

A Non-Interventional, Multicenter Study to Characterize the Socio-Demographics, Clinical Characteristics, and Management of Generalized Pustular Psoriasis Patients in Spain: IMPULSE Study

INTRODUCTION

Generalized pustular psoriasis (GPP) is a chronic, rare, and potentially life-threatening skin condition characterized by flares comprising widespread sterile pustules and systemic inflammation. Both the rarity and heterogeneity of the disease have made GPP classification and standardization of clinical criteria challenging. Before the approval of spesolimab (IL-36R antibody) in 2022, there were no approved treatments in the USA or Europe for GPP flares. Treatment for GPP has amounted to off-label use of medicines approved to treat plaque psoriasis. Our aim was to describe the sociodemographics, clinical characteristics, and treatment patterns of patients with GPP in Spain.

METHODS

Non-interventional, descriptive, multi-center, retrospective chart review of patients diagnosed with GPP in Spain.

RESULTS

56 patients (50% women) were included, with a mean (standard deviation, SD) age at diagnosis of 53.7 (20.5) and a mean (SD) time of follow-up of 3.7 (3.1) years. In 80% of patients, GPP diagnosis was associated with a flare and 67.3% had known risk factors for GPP (such as previous diagnosis or family history of plaque psoriasis, comorbidities, smoking or stress). Hypertension and plaque psoriasis were the most frequent comorbidities (44.6% each). The number of GPP flares per patient-year was 0.55 with (range 0-4) a mean (SD) body surface area involvement of 21.3% (19.1). The most frequent manifestations of GPP flares were pustules (88.5%), erythema (76.9%), and scaling (76.9%). Additionally, 65.4% of patients had plaque psoriasis, 53.8% had unspecified skin lesions, and 30.8% experienced pain. The treatments used for GPP flares were off-label conventional systemic drugs (75%), mostly corticosteroids, cyclosporine, and acitretin. In the periods between flares, off-label biologics were used in 56.5% of patients. During the study period, 9 patients (16.1%) had at least one complication and 5 of them required hospitalization.

CONCLUSION

This is the first multicenter study in Spanish GPP patients. Most patients were in their fifties, with personal or family history of plaque psoriasis, stress, smoking and a wide range of comorbidities and complications. Even though the number of flares per patient/year was 0.55, there was variability between patients. Both off-label conventional systemics and off-label biologics were used for flare management without a clear treatment pattern.

New and Emerging Treatments for Generalized Pustular Psoriasis: Focus on IL-36 Receptor Inhibitors

Generalized Pustular Psoriasis (GPP) is a rare and severe subtype of psoriasis that significantly impacts patients' quality of life. Until recently, no specific treatment modalities were available, and treatment for GPP followed the guidelines for the treatment of plaque psoriasis, consisting of conventional treatments, such as retinoids, methotrexate, and even biologics, which although effective in some cases, may be associated with significant side effects, necessitating more effective and safe options. The pathophysiology of Generalized Pustular Psoriasis is complex and not fully understood, but there is some overlap with the pathogenesis of Plaque Psoriasis. In GPP, the innate immune system seems to play a more significant role, with the interleukin (IL)-36 pathway being fundamentally involved. Spesolimab and imsidolimab, two recently developed therapeutic agents, target the IL-36 inflammatory pathway by binding to the IL-36 receptor (IL-36R). Both biologics have already been evaluated in phase 1 and 2 clinical trials and have shown promising results in terms of safety and efficacy. IL-36 receptor inhibitors demonstrated great efficacy and good safety profile in the management of patients with GPP, demonstrating their potential to emerge as a leading treatment option. This review aims to explore and summarize the current scientific literature on the most recently developed treatments for GPP.

Combination of secukinumab and acitretin for generalized pustular psoriasis: A case report and review of literature

Generalized pustular psoriasis (GPP) is characterized by painful and occasionally disfiguring cutaneous manifestations with sepsis-like systemic symptoms, and is a rare severe variant of psoriasis. Currently, there is no standard treatment for GPP. Here, we report a case of a female patient with ankylosing spondylitis (AS) and mild scalp psoriasis, who developed GPP and alopecia following three courses of adalimumab therapy. The patient's condition gradually improved following cessation of adalimumab and treatment with secukinumab and acitretin. After eight weeks of treatment, the patient achieved almost complete clearance of her psoriasis, her alopecia improved, and her AS was relieved. Therefore, we believe that a combination of secukinumab with acitretin may be a rational approach for the treatment of severe GPP.

Targeted review of IL36RN mutations in patients with generalised pustular psoriasis

Background

Generalised pustular psoriasis (GPP) is a rare and chronic skin disease historically treated with therapies that were originally intended to treat plaque psoriasis (PsO). However, GPP and plaque PsO have distinct pathogeneses and clinical courses.

Objectives

This study aimed to further characterise the unique genetic background of GPP by summarising evidence on the frequency and type of IL36RN gene mutation, a gene that normally suppresses proinflammatory responses, in patients with GPP compared to patients with GPP and plaque PsO, and patients with plaque PsO only.

Methods and Results

A targeted literature review was conducted to identify studies reporting IL36RN mutations and/or HLA-Cw6 allele frequency in patients with GPP. Meta-analyses showed a significantly higher rate of IL36RN mutations in the GPP-only population compared to the GPP + plaque PsO population (OR 3.51; 95% CI 2.29, 5.38). Monoallelic mutations of IL36RN were found in up to 33.3%, and biallelic mutations in up to 73.2% of patients with GPP (GPP-only and GPP + plaque PsO), in contrast with mono- and biallelic frequencies of only 0%-11.9% and 0%, respectively, in patients with plaque PsO only. Mean age-of-onset ranged from 5.9 to 48.9 years old, with most studies reporting a GPP age-of-onset between 20 and 40 years old. Twenty-one mutations were identified in the biallelic state and three in monoallelic. The most reported mutations were c.115 + 6T > C (p. Arg10ArgfsX1) (18 studies); c.227 C > T (p.Pro76Leu) (10 studies); and c.338 C > T (p.Ser113Leu) (8 studies). Mutations varied depending on geography and ethnicity, with the most frequently reported mutation predominantly reported in East Asian studies and international studies that included Asian patients. Rates of HLA-Cw6, the risk allele most strongly associated with plaque PsO, were 0%-28.6% for patients with GPP, similar to rates in the general population (10.5%-20%).

Conclusion

Considering the differences between GPP and plaque PsO in aetiology and disease symptoms, effective, GPP-specific treatment options are needed, and recent research suggests that blockade of IL-36 signalling may be an effective target for treatment of GPP.

Acquired diffuse palmoplantar erythema with keratoderma in Chinese patients with pustular psoriasis: A predictor for IL36 receptor antagonist c.115+6T>C mutation?

Several studies have suggested that mutation of the interleukin 36 receptor antagonist gene (IL36RN) is related to generalized pustular psoriasis (GPP), and the presence of IL36RN mutation may affect the clinical manifestations and treatment responses. However, genetic testing is not routinely available in clinical practice for the diagnosis of GPP. Previously, GPP patients with acrodermatitis continua of Hallopeau (ACH) were found to have a high percentage of carrying IL36RN mutation. In this study, we reported six patients with pustular psoriasis presenting as diffuse palmoplantar erythema with keratoderma among 60 patients who carried IL36RN mutation. ACH was present in five patients and five patients had acute flare of GPP. This unique presentation may serve as a predictor for IL36RN mutation in patients with pustular psoriasis, similar to ACH.

Increased neutrophil-derived IL-17A identified in generalized pustular psoriasis

Generalized pustular psoriasis (GPP) is considered to be a distinct clinical entity from psoriasis vulgaris (PV), with different clinical and histological manifestations. The pathogenesis of GPP has not been thoroughly elucidated, especially in those patients lacking interleukin (IL)36RN. In present study, we performed RNA sequence analysis on skin lesions from 10 GPP patients (4 with and 6 without IL36RN mutation) and 10 PV patients without IL36RN mutation. Compared with PV, significantly overexpressed genes in GPP patients were enriched in IL-17 signalling pathway (MMP1, MMP3, DEFB4A and DEFB4B, etc.) and associated with neutrophil infiltration (MMP1, MMP3, ANXA and SERPINB, etc.). GPP with IL36RN mutations evidenced WNT11 upregulation and IL36RN downregulation in comparison to those GPP without IL36RN mutations. The expression of IL-17A/IL-36 in skin or serum and the origin of IL-17A in skin were also investigated. IL-17A expression in skin was significantly higher in GPP than PV patients, whereas, there were no differences in skin IL-36α/IL-36γ/IL-36RA or serum IL-17A/IL-36α/IL-36γ between GPP than PV. Besides, double immunofluorescence staining of MPO/IL-17A or CD3/IL-17A further confirmed that the majority of IL-17A in GPP skin was derived from neutrophils, but not T cells. These data emphasized the role of neutrophil-derived IL-17A in the pathogenesis of GPP with or without IL36RN mutations. Targeting neutrophil-derived IL-17A might be a promising treatment for GPP.

Pustular psoriasis: A distinct aetiopathogenic and clinical entity

Pustular psoriasis is a distinct subset of psoriasis that presents with involvement of the skin in the form of sterile pustules along with systemic manifestations. Though it has been conventionally grouped under the umbrella of psoriasis, recent research has shed light on its pathogenetic mechanisms associated with the IL-36 pathway, which is distinct from conventional psoriasis. Pustular psoriasis in itself is a heterogeneous entity consisting of various subtypes, including generalised, localised, acute, and chronic forms. There is confusion regarding its current classification as entities like deficiency of IL-36 antagonist (DITRA) which are closely related to pustular psoriasis both in their pathogenetic mechanism and its clinical manifestations, are not included under pustular psoriasis. Entities like palmoplantar pustulosis, which presents with similar clinical features but is pathogenetically distinct from other forms of pustular psoriasis, are included under this condition. Management of pustular psoriasis depends upon its severity; while some of the localised variants can be managed with topical therapy alone, the generalised variants like Von Zumbusch disease and impetigo herpetiformis may need intensive care unit admission and tailor-made treatment protocols. The advent of newer biologics and better insight into the pathogenesis of pustular psoriasis has opened the way for newer therapies, including tumour necrosis factor-alpha inhibitors, interleukin-1 inhibitors, interleukin-17 inhibitors, and granulocyte monocyte apheresis. It continues to be an enigma whether pustular psoriasis is actually a variant of psoriasis or an entirely different disease entity, though we feel that it is an entirely different disease process.

Spesolimab for the Treatment of Generalized Pustular Psoriasis

Generalized pustular psoriasis (GPP) is a rare but severe skin inflammatory disorder characterized by the eruption of widespread sterile neutrophilic pustules, often accompanied by systemic inflammation. Given its life-threatening potential, GPP requires prompt accurate diagnosis and effective treatment, but its rarity and relapsing-remitting nature pose challenges in performing large-scale randomized controlled clinical trials. Established international guidelines are currently lacking and management guidance often follows that for plaque psoriasis. However, while it can co-exist with plaque psoriasis and has traditionally been classified as a most severe form of psoriasis, GPP is now recognized as a distinct entity, with its own clinicopathological, autoinflammatory, immunologic and genetic features. Research conducted over the past decade revealed that an imbalance of interleukin (IL)-36 signaling favoring the proinflammatory activity is the central driver of the pathogenesis of GPP, thereby laying the groundwork for the development of targeted therapies for the disease. This article reviews the evidence thus far on spesolimab, a selective humanized antibody against the IL-36 receptor that was recently licensed in Europe and the United States for the treatment of GPP flares in adults. In phase II, randomized controlled clinical trials, spesolimab led to rapid and effective skin clearance in patients experiencing a GPP flare and demonstrated superiority to placebo in preventing flares for up to 48 weeks with maintenance treatment, with reassuring safety and tolerability profiles. Spesolimab is considered to be a first-in-class medication establishing itself as the standard of care for the treatment of GPP flares, thus changing the paradigm of the management of GPP to a new era of scientifically- and evidence-based targeted therapy for this distinctive disease.

Knowledge Mapping and Research Hotspots of Generalized Pustular Psoriasis: A Bibliometric Analysis from 2003 to 2023

Background

Generalised pustular psoriasis (GPP) is a chronic inflammatory skin disease. We aimed to visualize the research hotspots and trends of GPP using bibliometric analysis to enhance our comprehension of the future advancements in both basic science and clinical research.

Methods

Relevant publications from July 2003 to July 2023 were obtained from the Web of Science Core Collection on July 12, 2023. The analysis of countries, institutions, authors, references, and keywords associated with this subject was conducted through the utilisation of CiteSpace 6.2.R4, VOSviewer 1.6.18, and Microsoft Excel 2019.

Results

A total of 578 papers were analyzed, authored by 2758 researchers from 191 countries/regions and 1868 institutions, published in 174 academic journals. There was an overall upward trajectory in the volume of annual publications, accompanied by a gradual intensification of research interest in GPP. The United States, UDICE-French Research Universities, and Akiyama M of Nagoya University were the most productive and influential country, institution, and author, respectively. The Journal of Dermatology ranked first with the highest publications, and the Journal of the American Academy of Dermatology received the most citations. High-frequency keywords included "generalized pustular psoriasis", "psoriasis, interleukin-36", "plaque psoriasis", "skin-disease", and "antagonist deficiency". Recent research focuses have included "safety", "secukinumab", "spesolimab", "ap1s3 mutations", and "interleukin-36". Burst detection analysis of keywords showed that "moderate", "ixekizumab treatment", "mutations", "efficacy", and "safety" are current research frontiers in this field.

Conclusion

This bibliometric analysis delineated the landmark publications in GPP that have defined current research hotspots and development trends, notably the applications, efficacy, and safety of biological agents. Future research endeavors are warranted to explore other biological therapeutic options for both acute GPP and the long-term management of chronic GPP.

The role of the interleukin-36 axis in generalized pustular psoriasis: a review of the mechanism of action of spesolimab

Generalized pustular psoriasis (GPP) is a rare, chronic, inflammatory skin disorder characterized by recurrent flares associated with skin erythema, desquamation, and widespread superficial sterile pustules, which may be severe ("lakes of pus"). Systemic symptoms are often present, including malaise, fever, and skin pain. In GPP, innate immune responses are driven by abnormal activation of the interleukin (IL)-36-chemokine-neutrophil axis and excessive neutrophil infiltration. This review highlights the IL-36 pathway in the context of the IL-1 superfamily and describes how unopposed IL-36 signaling can lead to the development of GPP. Targeted inhibition of the IL-36 receptor (IL-36R) is an attractive therapeutic strategy in the treatment of GPP, including flare prevention and sustained disease control. Spesolimab is a first-in-class, humanized, monoclonal antibody that binds specifically to the IL-36R and antagonizes IL-36 signaling. Spesolimab was approved by the US Food and Drug Administration in September 2022 to treat GPP flares in adults and was subsequently approved for GPP flare treatment in other countries across the world. Anti-IL-36R therapy, such as spesolimab, can mitigate flares and address flare prevention in GPP, presumably through rebalancing IL-36 signaling and modulating the pro-inflammatory response of the downstream effectors.

A narrative review of the socioeconomic burden associated with generalised pustular psoriasis

Generalised pustular psoriasis (GPP) is a rare, chronic and life-threatening inflammatory skin disease characterised by widespread eruption of sterile pustules. With the approval of a GPP flare treatment in several countries occurring only recently, the socioeconomic burden associated with GPP is not well established. To highlight current evidence for patient burden, healthcare resource utilization (HCRU) and costs associated with GPP. Patient burden results from serious complications including sepsis and cardiorespiratory failure causing hospitalization and death. HCRU is driven by high hospitalization rates and treatment costs. The mean duration of a GPP hospital stay ranges from 10 to 16 days. A quarter of patients require intensive care, and the mean intensive care stay is 18 days. In comparison to patients with plaque psoriasis (PsO), patients with GPP have: a 64% higher score on the Charlson Comorbidity Index; higher hospitalization rates (≤36.3% vs. ≤23.3%); lower overall quality of life, and higher symptom scores for pain, itch, fatigue, anxiety and depression; direct costs associated with treatment 1.3- to 4.5-fold higher; higher rates of disabled work status (20.0% vs. 7.6%); and increased presenteeism (i.e. worse impairment at work), impaired daily activities, and medically related absenteeism. Current medical management and drug treatment utilising non-GPP-specific therapies impose a significant patient and direct economic burden. GPP also imposes an indirect economic burden by increasing work productivity impairment and medically related absenteeism. This high level of socioeconomic burden reinforces the need for new therapies with proven efficacy in the treatment of GPP.

Transcriptomic responses of peripheral blood mononuclear cells to cyclosporin and etanercept in a female infant with juvenile generalized pustular psoriasis

Generalized pustular psoriasis (GPP) is a rare but severe form of psoriasis. An early onset of the diseases is correlated with mutations among IL36RN, CARD14, AP1S3, MPO and SERPINA3 genes. Systemic biological agents including anti-TNF-α, anti-IL-17, anti-IL-12/IL-23, anti-IL1R, anti-IL1β and anti-IL-36R act as novel treatment methods for GPP. Herein we report a female infant clinically diagnosed with GPP since she was 10-month-old. Results of whole-exome sequencing (WES) and Sanger sequencing revealed a reported heterozygous IL36RN (c.115+6T>C) and another reported heterozygous SERPINA3 frame-shifting variant (c.1247_1248del). Initial cyclosporin treatment for the patient led to a partial remission of the symptoms. However, the patient reached nearly total remission of pustules and erythema after anti-TNF-α inhibitor etanercept treatment. Results of further RNA sequencing (RNA-seq) done on peripheral blood mononuclear cells correlated with the clinical responses, showing that cyclosporin suppressed a portion of the neutrophil-related genes, while most genes associated with neutrophil activation, neutrophil-mediated immunity and degranulation were downregulated by the subsequent etanercept treatment. We report this case to demonstrate WES and RNA-seq in combination could come in handy in reaching a precise diagnosis and in evaluating or even predicting the molecular alterations underlying clinical treatment effectiveness.

Current management of generalized pustular psoriasis

Generalized pustular psoriasis (GPP) is a rare subset of psoriasis involving episodes of sterile pustules accompanied by inflammation and, often, systemic involvement. The inflammatory nature of GPP has potential for severe multisystem complications including high-output cardiac failure, infections, digestive system issues, and disfiguring or lethal acute flare episodes. The disease tends to have higher prevalence in females and Asians. The IL-1/IL-36 inflammatory pathway is a critical facet of GPP's pathology. Genetic mutations that are associated with GPP include modifications of Interleukin 36 Receptor Antagonist (IL36RN), Caspase Recruitment Domain Family Member 14 (CARD14), Adaptor Related Protein Complex 1 Subunit Sigma 3 (AP1S3), Myeloperoxidase (MPO) and Serpin Peptidase Inhibitor Clade A Member 3 (SERPINA3) genes. Treatment guidelines for GPP are not well-entrenched. Currently, only one GPP-specific treatment, the interleukin-36 receptor antagonist (IL-36Ra) spesolimab, has been approved for use in the United States. Additional anti-IL-36 pathway therapies are currently being developed. Other treatment options include other biologic therapies such as IL-17 inhibitors, IL-23 inhibitors and TNFα inhibitors. Non-biologic therapeutic options include retinoids, cyclosporine and methotrexate. Treatment options differ throughout the world; most countries utilize retinoids, cyclosporine and methotrexate as first-line non-biologic options. China and United Kingdom have no GPP-specific biologic therapies approved for use, while several biologic therapies are approved for use in Japan. This review aims to serve as an update on the current global management of GPP while also including relevant aspects of disease pathogenesis, diagnosis, clinical presentation, histopathology, aetiology and epidemiology.

Pathophysiology of generalized pustular psoriasis

Psoriasis is a chronic, immune-mediated skin disease that affects over 3% of adults in the United States. Psoriasis can present in several clinical forms. Of these, generalized pustular psoriasis is an acute, severe form, associated with increased morbidity and mortality. Unlike the more common plaque psoriasis, which is thought to feature dysregulation of the adaptive immune system, generalized pustular psoriasis reflects heightened autoinflammatory responses. Recent advances in genetic and immunological studies highlight a key role of the IL-36 immune axis in the pathogenesis of generalized pustular psoriasis. In this article, we review the psoriatic subtypes and discuss diagnostic criteria of generalized pustular psoriasis, discuss several newly identified genetic variants associated with pustular disease in the skin, and discuss how these mutations shed light on pustular disease mechanisms. Furthermore, we gather insights from recent transcriptomic studies that similarly implicate a pathogenic role of the IL-36 immune axis in generalized pustular psoriasis.

Clinical profile of patients with acute generalized pustular psoriasis with and without IL36RN mutations in multi-ethnic Johor Bahru, Malaysia

Generalized Pustular psoriasis (GPP), a rare and potentially life-threatening auto-inflammatory disease, is associated with IL36RN mutations. Here, we analyse the prevalence of IL36RN mutations in our multi-ethnic GPP cohort and assess differences in the clinical profile of patients with (IL36RN-positive) and without (IL36RN-negative) mutations. IL36RN mutations were present in 17.7% of 137 GPP patients (29.7% of Chinese cases, 17.3% of Malay cases, but 0% of Indian patients). 92% of these individuals carried the c.115 + 6 T > C mutation. Male: female ratio was 1:2.3. Females predominate in both groups with no significant difference between IL36RN-positive and IL36RN-negative individuals. The overall mean age (±SD) at disease onset for GPP was 37.6 ± 17.2 years, but disease onset was significantly earlier in IL36RN-positive vs IL36RN-negative cases (mean age:30.6 ± 18.92 vs. 39.2 ± 16.49 years, p = 0.027). IL36RN-positive patients were less likely to have associated plaque psoriasis (52.4% vs. 83.5%, p-value = 0.002). There was no difference in the common clinical and laboratory manifestations or triggers of GPP between IL36RN-positive and -negative patients, except for geographic tongue which was significantly more common in IL36RN-positive patients (41.7% vs. 11.9%, p-value = 0.002). Annual flare rate was significantly higher in IL36RN-positive compared to IL36RN-negative (mean ± SD of 1.92 ± 1.32 vs. 1.46 ± 0.90, p = 0.041) cases. However, no significant difference in the rate of hospitalization and length of hospital stay was observed between the two groups. These observations demonstrate that IL36RN disease alleles occur with varying frequencies among Asian populations and are associated with a severe, early-onset clinical phenotype.

Genetics of Generalized Pustular Psoriasis: Current Understanding and Implications for Future Therapeutics

Psoriasis is a chronic inflammatory skin disease characterized by the appearance of clearly demarcated erythematous and scaly plaques. It can be divided into various types, including plaque, nail, guttate, inverse, and pustular psoriasis. Plaque psoriasis is the most commonly occurring type, though there is another rare but severe pustular autoinflammatory skin disease called generalized pustular psoriasis (GPP), which manifests with acute episodes of pustulation and systemic symptoms. Though the etiopathogenesis of psoriasis is not yet fully understood, a growing body of literature has demonstrated that both genetic and environmental factors play a role. The discovery of genetic mutations associated with GPP has shed light on our comprehension of the mechanisms of the disease, promoting the development of targeted therapies. This review will summarize genetic determinants as known and provide an update on the current and potential treatments for GPP. The pathogenesis and clinical presentation of the disease are also included for a comprehensive discussion.

[Psoriasis in children and adolescents : Short update and guideline-based treatment]

Psoriasis is nowadays regarded as a multifactorial, inflammatory, immune-mediated systemic condition with predominant involvement of the skin. It starts in about one third of cases in childhood and adolescence and is often accompanied by marked impairment of the quality of life of sufferers and their parents. Aside from genetic disposition, trigger factors such as streptococcal infections are notably involved in manifestation and in exacerbations. The harmful role of comorbidities even in the young, particularly of obesity, has been well documented. Treatment options have considerably improved following the approval of five biologic agents in childhood but are still insufficiently used. The present article gives a short overview of current knowledge and the recommendations of the updated German guideline. Besides frequent types, unusual presentations such as pustular psoriasis, psoriasis dermatitis, and paradoxical psoriasis induced by tumor necrosis factor alpha (TNF-α) inhibitors are addressed.

Newly revealed variants of SERPINA3 in generalized pustular psoriasis attenuate inhibition of ACT on cathepsin G

Generalized pustular psoriasis (GPP) is an autoinflammatory skin disease whose pathogenesis has not yet been fully elucidated. Alpha-1-antichymotrypsin(ACT) is a protein encoded by the SERPINA3 gene and an inhibitor of cathepsin G. One study of a European sample suggested that the loss of ACT function caused by SERPINA3 mutation is implicated in GPP. However, the role of SERPINA3 in the pathogenesis of GPP in other ethnic populations is unclear. To explore this, seventy children with GPP were performed next-generation sequencing to identify rare variants in the SERPINA3 gene. Bioinformatic analysis and functional tests were used to determine the effects of the variants, and a comprehensive analysis was performed to determine the pathogenicity of the variants and whether they are associated with GPP. One rare deletion and three rare missense variants were identified in the SERPINA3 gene in GPP. The deletion variant c.1246_1247del was found to result in a mutant protein with an extension of 10 amino acids and a C-terminal of 20 amino acids that was completely different from the wild-type. This mutant was found to impede secretion of ACT, thus failing to function as an inhibitor of cathepsin G. Two missense variants were found to reduce the ability of ACT to inhibit cathepsin G enzymatic activity. The association analysis suggested that the deletion variant is associated with GPP. This study identified four rare novel mutations of SERPINA3 and demonstrated that three of these mutations result in loss of function, contributing to the pathogenesis of pediatric-onset GPP in the Asian population.

Identification of the BTN3A3 gene as a molecule implicated in generalized pustular psoriasis in a Chinese population

The discovery of pathogenic variants provided biological insight into the role of host genetic factors in generalized pustular psoriasis (GPP). However, not all those affected by GPP carry mutations in the reported genes. To comprehensively explore the molecular pathogenesis of GPP, whole-exome sequencing was performed and two loci were identified with exome-wide significance via single variant association analysis: rs148755083 in the IL36RN gene (P_combined = 1.19 × 10^-18, OR = 8.26) and HLA-C*06:02 within the MHC region (P_combined = 8.38 × 10^-12, OR = 2.98). Gene burden testing revealed that BTN3A3 correlated with GPP (P_combined = 1.14 × 10^-10, OR = 5.59). Subtype analysis showed that IL36RN and BTN3A3 were both significantly associated with GPP alone and GPP with psoriasis vulgaris (PV), while a correlation with HLA-C*06:02 was only observed in GPP with PV. Functional analysis revealed that BTN3A3 regulated cell proliferation and inflammatory balance in GPP. In particular, loss of function of BTN3A3 activated NF-κB and promoted the production of inflammatory cytokines by inhibiting IL-36Ra expression to disturb the IL-1/IL-36 inflammatory axis and enhance the TNF-α-mediated pathway. Our findings identify BTN3A3 as, to our knowledge, a previously unreported pathogenic determinant, expanding our understanding of the genetic basis of GPP.

Prevalence, comorbidities and mortality of generalized pustular psoriasis: A literature review

Generalized pustular psoriasis (GPP) is a rare auto-inflammatory skin disease characterised by acute episodes of sterile pustule formation. Diagnosis and treatment of the disease have historically been complicated by a lack of awareness, and no consistent global definition or clinical coding standards. Now acknowledged as a distinct clinical entity with a recognised genetic component, GPP can take a serious and life-threatening course due to systemic inflammatory complications and its association with various comorbidities. As with other rare diseases, there are significant challenges to understanding the epidemiology of GPP, notably a small patient population, non-standardised study methodologies and ethnic differences in its presentation. A clearer understanding of GPP is therefore required for clinicians to better manage patients with this rare condition. In this review article, we present an overview of the available data on GPP prevalence estimates in key demographics and report the frequency of genetic mutations associated with the disease. We detail the incidence of known comorbidities and summarise the data on mortality and assigned causes of death. Lastly, we discuss the various factors that impact the collection, interpretation and comparison of these data.

Generalized Pustular Psoriasis: A Review on Clinical Characteristics, Diagnosis, and Treatment

Generalized pustular psoriasis (GPP) is a rare, chronic, and severe inflammatory skin disorder characterized by sudden eruption of sterile pustules, often accompanied by systemic inflammation. GPP flares can be life-threatening if untreated, owing to potential serious complications such as sepsis and cardiovascular failure. Diagnosis and clinical measurement of disease severity in GPP are often difficult. Lack of standardized criteria in the international guidelines and the heterogeneity of cutaneous and extracutaneous symptoms make the diagnosis of GPP difficult. Clinical criteria for description and diagnosis of pustular conditions, including GPP, are variable and there is no specific agreement on commonly sustained concepts. Differentiation of GPP from other similar conditions/diseases is important and requires careful assessments. The evidence that supports current topical or systemic therapies is largely based on case reports and small studies. Some biologic agents that target key cytokines involved in the activation of inflammatory pathways have been used as treatments for GPP. Recently, spesolimab, an IL-36R antagonist, has been approved in the USA and Japan for the treatment of GPP flares in adults, but there are no currently approved treatments for GPP in Europe. The IL-36 pathway has recently emerged as a central axis driving the pathogenic inflammatory mechanisms of GPP. Biologic agents that inhibit the IL-36 pathway have shown efficacy and safety in patients with GPP, addressing a generally considered unmet medical need.

[Psoriasis in children and adolescents]

Psoriasis is nowadays regarded as a multifactorial, inflammatory, immune-mediated systemic condition with predominant involvement of the skin. It starts in about one third of cases in childhood and adolescence and is often accompanied by marked impairment of the quality of life of sufferers and their parents. Aside from genetic disposition, trigger factors such as streptococcal infections are notably involved in manifestation and in exacerbations. The harmful role of comorbidities even in the young, particularly of obesity, has been well documented. Treatment options have considerably improved following the approval of five biologic agents in childhood but are still insufficiently used. The present article gives a short overview of current knowledge and the recommendations of the updated German guideline. Besides frequent types, unusual presentations such as pustular psoriasis, psoriasis dermatitis, and paradoxical psoriasis induced by tumor necrosis factor alpha (TNF-α) inhibitors are addressed.

Pustular psoriasis with a focus on generalized pustular psoriasis: classification and diagnostic criteria. An Italian expert consensus

Generalized pustular psoriasis (GPP) is a severe and life-threatening systemic disease associated with significant morbidity and mortality. Recent progress has been made in understanding the pathogenetic pathways involved in GPP and an intricate interaction between innate and adaptive immune mechanisms has been suggested. Despite formal consensus guidelines on pustular psoriasis currently available in the literature, the definitions and classifications of GPP used across studies were inconsistent. Consequently, there are no unified criteria that can be universally adopted for precise diagnosis, classification and effective treatment of GPP patients with new targeted drugs. The aim of this review was to collect all the main evidence on available diagnostic criteria for GPP and to establish recommendations in order to promote a better stratification and therapeutic management of this severe and heterogeneous disease.

A Review of the Clinical Trial Landscape in Psoriasis: An Update for Clinicians

As our understanding of the pathogenesis of psoriasis has evolved over the past two decades, so has the number of treatment options. The introduction of biologic agents targeting specific cytokines in the interleukin (IL)-23/IL-17 pathway has proven successful in promoting skin clearance among patients. However, their use is often limited owing to cost, parenteral administration, and possible reduced efficacy over time. Topical therapies have also seen limited advancement, with agents such as corticosteroids and vitamin D derivatives remaining the mainstay of treatment, despite side effects limiting their long-term use. New therapeutic agents are needed to improve disease management for patients. In this review, we summarize pipeline and recently approved therapies undergoing clinical trials for psoriasis during a 12-month search period (30 June 2021 to 30 June 2022) using ClinicalTrials.gov. New-generation biologics and oral small molecules in phase II or III development were included, and pivotal data identified through various search modalities (PubMed, conference presentations, etc.) evaluating each drug candidate will be discussed. Topical therapies will also be discussed in line with recent US Food and Drug Administration approvals. As new therapies continue to enter the treatment landscape, long-term data and comparative trials will be needed to better understand their place among existing therapeutic agents.

An analysis of psoriasis hospitalisation in Thailand

Psoriasis hospitalisation is not frequently reported. The objective of this study was to determine (1) the clinical, laboratory and treatment features of patients with psoriasis hospitalised due to flare-up and (2) other causes of admission of patients with psoriasis. We retrospectively reviewed data on 48 patients admitted due to psoriasis flare-up and 1908 patients with psoriasis admitted due to concomitant illnesses or comorbidities. The study period was 2005-2021. The latter group was compared with 821,804 patients without psoriasis admitted during the period. Of the 48 cases, 37.5% had erythroderma, and 62.5% had generalised pustular psoriasis (GPP). Women (68.8%) predominated, especially in the GPP group (76.7%). The mean age of admission with erythroderma (44.8 years) was higher than for GPP (32.1 years). Infection was the main trigger for psoriasis flare-up (46%). Abnormalities in liver function tests were found in 33.3% of the cases. These abnormalities usually subsided 1-2 months after skin improvement (83.4%). Acitretin was the most prescribed drug for GPP (81.4%), whereas topical treatment alone (50%) was the most frequent erythroderma therapy. Intensive care was needed by 9.3% of patients with GPP. In the psoriasis group admitted due to concomitant illnesses or comorbidities, admission due to digestive and infectious causes was significantly higher for psoriasis patients. Our study showed that trend of psoriasis admission due to disease flare-up was not significantly changed even in the era of biologics. We believed that patient education on avoiding the common precipitating factors of psoriasis flare-up and good self-care is mandatory to reduce the risk of hospitalisation.

Generalized pustular psoriasis is a disease distinct from psoriasis vulgaris: evidence and expert opinion

INTRODUCTION

Generalized pustular psoriasis (GPP) is a rare, severe, clinically heterogeneous disease characterized by flares of widespread, noninfectious, macroscopically visible pustules that occur with or without systemic inflammation, and are associated with significant morbidity and mortality. Historically, GPP has been classified as a variant of psoriasis vulgaris (PV, or plaque psoriasis); however, accumulating evidence indicates that these are distinct conditions, requiring different treatment approaches.

AREAS COVERED

In this perspective article we review evidence that supports the classification of GPP as distinct from PV.

EXPERT OPINION

The histopathologic and clinical appearance of GPP is distinct from that of PV and fundamental differences exist between the two conditions in terms of genetic causes and expression-related mechanisms of disease development. GPP results from dysregulation of the innate immune system, with disruption of the interleukin (IL)-36 inflammatory pathway, induction of inflammatory keratinocyte responses, and recruitment of neutrophils. PV is driven by the adaptive immune system, with a key role played by IL-17. Considering GPP as a separate disease will enable greater focus on its specific pathogenesis and the needs of patients. Many treatments for PV have insufficient efficacy in GPP and a therapeutic approach developed specifically for GPP might lead to better patient outcomes.

Generalized pustular psoriasis: the new era of treatment with IL-36 receptor inhibitors

Generalized pustular psoriasis (GPP) is a rare yet severe variant of psoriasis, characterized by the eruption of superficial sterile pustules that appear suddenly and widely distributed, potentially life-threatening. It more commonly presents through recurrent acute flares triggered by stress, corticosteroid withdrawals, pregnancy, or infections. The pathogenesis of this disease is yet to be fully understood. Nevertheless, studies have suggested an important role of an IL-1 subfamily of cytokines, due to an imbalance of the IL-36 axis favoring of pro-inflammatory activity. The therapeutic intervention for this condition is still a challenge as its rarity and scarce available information contribute to the absence of specific treatment. Current options stand on small, open-label trials or follows standard treatment for plaque psoriasis. Spesolimab and imsidolimab are two IL-36 receptor inhibitors which completed phase 1 and 2 trials with a good efficacy and safety profile in the treatment of this disease, including in the fast control of its acute flares. The most common adverse events reported with spesolimab were mild to moderate infections, and imsidolimab was well tolerated. GPP clinical trials remain to have their small sample size as a major limitation, but IL-36 receptor inhibitors are promising therapeutic options currently under investigation.

Generalized pustular psoriasis: overview of the status quo and results of a panel discussion

Generalized pustular psoriasis (GPP) is a rare, severe, potentially life-threatening, autoinflammatory, neutrophilic skin disease that may be accompanied by fever and leukocytosis. This paper describes the current state of knowledge on GPP in terms of classification, (differential) diagnosis and prevalence. We present a comparison of the genetics and pathoimmunology of GPP and psoriasis vulgaris with the central mechanisms of autoimmunology and autoinflammation. The currently available therapeutic options, expert recommendations for therapy, and data from early clinical trials investigating targeted therapies will be summarized. We present the results of our discussion with 13 experts for psoriasis vulgaris and GPP and give an integrated overview of indication and therapy based on our personal experience and present an outlook on further research questions. Collectively, this article highlights the high unmet need in GPP, as there exists no satisfactory method of diagnosis or treatment to date and new treatment options will be of great therapeutic benefit to those affected.

Treatment Options and Goals for Patients with Generalized Pustular Psoriasis

Generalized pustular psoriasis (GPP) is a rare, severe neutrophilic skin disorder characterized by sudden widespread eruption of superficial sterile pustules with or without systemic inflammation. GPP flares can be life-threatening if untreated due to potential severe complications such as cardiovascular failure and serious infections. Currently, there are no GPP-specific therapies approved in the USA or Europe. Retinoids, cyclosporine, and methotrexate are the most commonly used non-biologic therapies for GPP. The evidence that supports the currently available treatment options is mainly based on case reports and small, open-label, single-arm studies. However, recent advances in our understanding of the pathogenic mechanisms of GPP and the identification of gene mutations linked to the disease have paved the way for the development of specific targeted therapies that selectively suppress the autoinflammatory and autoimmune mechanisms induced during GPP flares. Several biologic agents that target key cytokines involved in the activation of inflammatory pathways, such as tumor necrosis factor-α blockers and interleukin (IL)-17, IL-23, and IL-12 inhibitors, have emerged as potential treatments for GPP, with several being approved in Japan. The evidence supporting the efficacy of these agents is mainly derived from small, uncontrolled trials. A notable recent advance is the discovery of IL36RN mutations and the central role of IL-36 receptor ligands in the pathogenesis of GPP, which has defined key therapeutic targets for the disease. Biologic agents that target the IL-36 pathway have demonstrated promising efficacy in patients with GPP, marking the beginning of a new era of targeted therapy for GPP.