Association between mutation of interleukin 36 receptor antagonist and generalized pustular psoriasis: A PRISMA-compliant systematic review and meta-analysis

Literature review and expert opinion on diagnosis and current management of generalized pustular psoriasis

INTRODUCTION

Generalized pustular psoriasis (GPP) is a rare, chronic, systemic, autoinflammatory disease characterized by the eruption of sterile pustules, often accompanied by more general symptoms, such as fever, fatigue, and a burning sensation in the skin. GPP can be potentially life-threatening, if untreated, as it can lead to complications, such as sepsis and heart failure.

AREAS COVERED

In this literature review and expert opinion article, we provide an overview of the epidemiology, pathogenesis, clinical presentation, diagnosis, and treatment of GPP. Eleven dermatologists representing seven different Italian regions considered relevant evidence in the literature to discuss the current diagnosis and treatment of GPP. The expert panel of dermatologists identified several weaknesses in the current clinical management of GPP.

EXPERT OPINION

There is an inconsistent definition and classification of the disease across the literature, which can lead to misdiagnosis and delay in disease treatment. Furthermore, there are no international and standardized clinical guidelines on disease management, especially in Europe. There is a profound need for the development of novel therapeutic agents with sustained efficacy to decrease the impact of the comorbidities and mortality associated with GPP, prevent the onset of complications, and support the unmet needs of these patients.

Prevalence, incidence, mortality and healthcare resource use for generalized pustular psoriasis, palmoplantar pustulosis and plaque psoriasis in England: a population-based cohort study

BACKGROUND

Generalized pustular psoriasis (GPP) and palmoplantar pustulosis (PPP) are chronic inflammatory skin conditions. Accumulating evidence shows that GPP and PPP have different characteristics to plaque psoriasis and are distinct clinical entities.

OBJECTIVES

To assess the epidemiology, comorbidities, mortality and healthcare use for patients in England with GPP and PPP versus those with plaque psoriasis.

METHODS

We carried out a cohort study involving analyses of longitudinal electronic health record data in the Clinical Practice Research Datalink Aurum database and linked hospital and mortality data between 2008 and 2019. The primary study outcome was the incidence and prevalence rates of GPP, PPP and plaque psoriasis in England. Secondary outcomes included survival rates and healthcare resource use (HCRU) by disease type.

RESULTS

We identified 373 patients with GPP, 1828 with PPP and 224 223 with plaque psoriasis. Mean (SD) age was 55.9 (18.6) years for patients with GPP, 51.5 (16.4) years for those with PPP and 48.5 (19.1) years for those with plaque psoriasis; 62.5% and 65.9% of patients with GPP and PPP, respectively, were women, vs. 49.4% of those with plaque psoriasis. About half of patients were overweight or obese at baseline (GPP 48.6%, PPP 56.0%, plaque psoriasis 45.9%). The incidence rates for GPP, PPP and plaque psoriasis were 0.25 [95% confidence interval (CI) 0.21-0.28], 2.01 (95% CI 1.92-2.11) and 103.2 (95% CI 102.5-103.9) per 100 000 person-years, respectively. From 2008 to 2019, the prevalence rates per 100 000 persons ranged from 1.61 to 3.0 for GPP, from 1.1 to 18.7 for PPP and from 1771.0 to 1903.8 for plaque psoriasis. Survival rates were lower for patients with GPP, particularly those who were > 55 years of age and those with a history of one or more comorbidities in each cohort. HCRU was lower in the cohort with plaque psoriasis and highest in the cohort with GPP, particularly among those who had more than one GPP flare.

CONCLUSIONS

Our results provide further evidence that, in England, GPP is a distinct disease with different epidemiology, lower survival and higher HCRU than plaque psoriasis.

Whole exome sequencing identifies genetic markers of enterovirus susceptibility in East Asians

Introduction

Following acute enterovirus (EV) infection, outcomes vary based on factors like the immune response, viral cell entry receptor expression levels, tissue tropism, and genetic factors of both the host and virus. While most individuals exhibit mild, self-limited symptoms, others may suffer severe complications or prolonged infections that can lead to autoimmune disorders.

Methods

To elucidate host responses to EV infection, we performed whole exome sequencing on blood samples from both infected and uninfected individuals. Our initial focus was on genes encoding EV entry receptors-PSGL-1, SCARB2, and ANAXA2 for EV-A71, and CD155 for poliovirus-and on host genes ACBD3 and PI4KΒ, crucial for EV replication.

Results

Although no specific genetic variants directly associated with EV infection were identified, we discovered 118 variants across 116 genes enriched in East Asian populations through multi-layered variant filtering. These variants were further analyzed for their potential impacts on organs, biological processes, and molecular pathways. Phenome-wide association studies were conducted to refine our understanding of their contributions to EV infection susceptibility.

Discussion

Our findings aim to develop a predictive panel based on these 118 variants, which could help susceptible individuals during EV outbreaks, guiding targeted clinical interventions and preventative strategies.

Spesolimab for generalized pustular psoriasis: a review of two key clinical trials supporting initial US regulatory approval

Generalized pustular psoriasis (GPP) is a chronic, rare, and potentially life-threatening inflammatory disease, characterized by the rapid and widespread eruption of small, sterile pustules with surrounding skin erythema. Abnormal signaling of the interleukin-36 (IL-36) pathway appears to have a central role in GPP immunopathology, and provides a rational therapeutic target. Spesolimab is a first-in-class humanized monoclonal antibody that binds specifically to the IL-36 receptor, and antagonizes IL-36 signaling. Spesolimab obtained regulatory approval in the United States (US) in September 2022 for use in the treatment of GPP flares in adults, and was subsequently approved for GPP flare treatment in many other countries across the world. Recently, regulatory approval was granted for subcutaneous dosing of spesolimab for treatment of GPP when not experiencing a flare. Here, we review data from two key clinical trials that supported the initial US regulatory approval; namely, the phase 1 proof-of-concept trial (ClinicalTrials.gov ID, NCT02978690), and Effisayil™ 1 (NCT03782792), which remains the largest and only randomized clinical trial in patients experiencing GPP flares published to date. In the phase 1 proof-of-concept trial, a Generalized Pustular Psoriasis Physician Global Assessment (GPPGA) score of 0 or 1 (clear or almost clear skin) was attained in 5/7 (71%) patients by week 1 and in all 7 patients by week 4; and the mean percent improvement in the Generalized Pustular Psoriasis Area and Severity Index (GPPASI) score from baseline was 59.0% at week 1, 73.2% at week 2, and 79.8% at week 4. In Effisayil™ 1, a GPPGA pustulation subscore of 0 (no visible pustules) was achieved in 19/35 (54%) patients receiving spesolimab at the end of week 1, versus 1/18 (6%) receiving placebo (difference, 49 percentage points; 95% confidence interval [CI], 21 to 67; P<0.001); and a GPPGA total score of 0 or 1 was achieved by 15/35 (43%) patients in the spesolimab group, versus 2/18 (11%) patients in the placebo group (difference, 32 percentage points; 95% CI, 2 to 53; P = 0.02). Infections at week 1 were reported in 6/35 (17%) patients receiving spesolimab and in 1/18 (6%) patients receiving placebo. These data demonstrate the efficacy and safety of spesolimab in providing rapid and sustained clinical improvement for patients with GPP flares, which translates into improved quality of life, by offering a targeted therapy for 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.

Clinical and Disease Burden of Patients with Generalized Pustular Psoriasis: A Review of Real-World Evidence

Generalized pustular psoriasis (GPP) is a chronic, rare, and potentially life-threatening disease. There is limited understanding of patient characteristics in GPP and their correlation with disease progression or healthcare resource utilization. Our review aims to examine real-world evidence on these characteristics and the associated disease burden as related to economic and quality of life factors. Results showed that most patients with GPP experienced flares once a year, lasting from 2 weeks to 3 months, with > 80% of patients having residual disease post-flare, with/without treatment, indicating the long-term nature of GPP. The impact of GPP on patients' daily activities was significant, even in the absence of a flare. GPP adversely affected mental health, and anxiety and depression were reported regularly. Patients with GPP had more comorbidities, were prescribed more medication, and had more inpatient and outpatient visits than in matched plaque psoriasis or general population cohorts. Improving the education of healthcare providers in diagnosing GPP, defining disease flares, and managing the disease, as well as making globally accepted clinical guidelines for GPP treatment available, could help to reduce the burden on patients with GPP. Effective therapies that control and prevent GPP flares and manage chronic disease are needed.

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.

Deficiency of interleukin-36 receptor antagonist (DITRA): An analysis of 58 Chinese patients in a tertiary hospital in Taiwan

DITRA, acronym for deficiency of interleukin-36 receptor antagonist (IL36RN), leads to unopposed pro-inflammatory signalling which typically manifests as pustular psoriasis. In Asian patients, c.115 + 6 T > C mutation is the most common and important single-nucleotide variant in DITRA. We present the largest case series consisting of 58 DITRA patients carrying heterozygous or homozygous c.115 + 6 T > C mutation. The mean age of onset (±SD) was 20.74 (±20.86), and the median age of onset was 13 years old. Twelve patients (20.7%) had disease onset before the age of two. Twenty-two patients (37.9%) had disease onset between the ages of 2-18. Main clinical phenotype was generalized pustular psoriasis (GPP) with systemic symptoms (33 patients, 56.9%), followed by acrodermatitis continua of Hallopeau (ACH) (16 patients, 27.6%). Nearly half of our patients (27 patients, 46.6%) ever had ACH, and only three of them are free of ACH currently, which indicates that the development of ACH is relatively persistent and irreversible. Thirty-four patients (58.6%) had recurrent GPP and 29 patients (50%) have been admitted due to GPP flare. Compared to those with heterozygous (C/T) mutation, more patients carrying homozygous mutation (C/C) have recurrent episodes of GPP (C/T vs. C/C: 25.53 vs. 76.47%, p = 0.0367). Two patients with squamous cell carcinomas arising from the pustular psoriasis skin lesions were noted. Two patients had elevated serum IgG4 levels.

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.

Current understanding of genetic associations with delayed hypersensitivity reactions induced by antibiotics and anti-osteoporotic drugs

Drug-induced delayed hypersensitivity reactions (DHRs) is still a clinical and healthcare burden in every country. Increasing reports of DHRs have caught our attention to explore the genetic relationship, especially life-threatening severe cutaneous adverse drug reactions (SCARs), including acute generalized exanthematous pustulosis (AGEP), drug reactions with eosinophilia and systemic symptoms (DRESS), Stevens-Johnson syndrome (SJS), and toxic epidermal necrolysis (TEN). In recent years, many studies have investigated the immune mechanism and genetic markers of DHRs. Besides, several studies have stated the associations between antibiotics-as well as anti-osteoporotic drugs (AOD)-induced SCARs and specific human leukocyte antigens (HLA) alleles. Strong associations between drugs and HLA alleles such as co-trimoxazole-induced DRESS and HLA-B*13:01 (Odds ratio (OR) = 45), dapsone-DRESS and HLA-B*13:01 (OR = 122.1), vancomycin-DRESS and HLA-A*32:01 (OR = 403), clindamycin-DHRs and HLA-B*15:27 (OR = 55.6), and strontium ranelate (SR)-SJS/TEN and HLA-A*33:03 (OR = 25.97) are listed. We summarized the immune mechanism of SCARs, update the latest knowledge of pharmacogenomics of antibiotics- and AOD-induced SCARs, and indicate the potential clinical use of these genetic markers for SCARs prevention in this mini review article.

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.

The relationship of skin disorders, COVID-19, and the therapeutic potential of ginseng: a review

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has made significant impacts on global public health, including the development of several skin diseases that have arisen primarily as a result of the pandemic. Owing to the widespread expansion of coronavirus disease 19 (COVID-19), the development of effective treatments for these skin diseases is drawing attention as an important social issue. For many centuries, ginseng and its major active ingredients, ginsenosides and saponins, have been widely regarded as herbal medicines. Further, the anti-viral action of ginseng suggests its potential effectiveness as a therapeutic agent against COVID-19. Thus, the aim of this review was to examine the association of skin lesions with COVID-19 and the effect of ginseng as a therapeutic agent to treat skin diseases induced by COVID-19 infection. We classified COVID-19-related skin disorders into three categories: caused by inflammatory, immune, and complex (both inflammatory and immune) responses and evaluated the evidence for ginseng as a treatment for each category. This review offers comprehensive evidence on the improvement of skin disorders induced by SARS-CoV-2 infection using ginseng and its active constituents.

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.

Correlation of IL36RN and CARD14 mutations with clinical manifestations and laboratory findings in patients with generalised pustular psoriasis

Background

Generalized pustular psoriasis (GPP) is a chronic disease associated with genetic factors related to mutations of the interleukin 36 receptor antagonist gene (IL36RN) and the caspase recruitment domain 14 gene (CARD14). However, the relevance of these mutations to the clinical features and severity of GPP remains unclear.

Aims

Our objective was to correlate the presence of IL36RN and CARD14 mutations with the clinical and laboratory findings in patients with GPP.

Methods

This cross-sectional descriptive study was conducted in 64 subjects with GPP. Clinical manifestations were recorded and the severity was graded as mild, moderate, or severe. Routine laboratory tests were performed and blood samples were collected for Sanger sequencing. The clinical data of patients were compared among the different mutation groups.

Results

The two main variants of IL36RN were c.115+6T > C (p.Arg10ArgfsX1) and c.227C > T (p.Pro76Leu). The major CARD14 mutations were c.2458C > T (p.Arg820Trp), c.1641C > T (p.Arg547Ser), and c.1753G > A transitions.

Provocative factors were uncommon in the group with both IL36RN and CARD14 mutations. Drugs (unspecified), especially herbals, were the most common triggers. A history of psoriasis was frequent in patients with only CARD14 mutations, but fever was uncommon. The c.1641C > T mutation was associated with leukocytosis > 15000/mm3 and the c.1753G > A mutation was associated with hypoalbuminemia <3.8g/dL.

Both the c.115+6T > C and c.227C > T variants of IL36RN were associated with fever ≥38.5°C while the c.115+6T > C variant was also associated with geographic tongue.

No gene mutations were associated with the total severity and severity grades.

Limitations

Four patients without the two major IL36RN mutations were excluded from the study.

Conclusion

The presence of IL36RN and CARD14 mutations were associated with a history of psoriasis, various provocative factors, fever, leukocytosis, hypoalbuminemia, and geographic tongue. Further studies to explore the role of these mutations in therapeutic efficacy and disease outcomes are necessary.

Understanding Flares in Patients With Generalized Pustular Psoriasis Documented in US Electronic Health Records

Question

What are the differences in treatment between patients with generalized pustular psoriasis (GPP) with flares and those without flares?

Findings

In this cohort study comprising 1535 patients with GPP, with 271 of them having 513 documented flares, patients with flares had a higher comorbidity burden, were almost 3 times more likely to have inpatient visits, were more than twice as likely to have emergency department visits, and had higher use of almost all treatment classes. Despite this high level of severity, advanced treatments for GPP were very rarely used during flare episodes.

Meaning

This study suggests that there is a significant unmet need in the current treatment of GPP and its flares.

Importance

Other than single-center case studies, little is known about generalized pustular psoriasis (GPP) flares.

Objective

To assess GPP flares and their treatment, as well as differences between patients with and patients without flares documented in US electronic health records (EHRs).

Design, Setting, and Participants

This retrospective cohort study included adult patients with GPP (International Statistical Classification of Diseases and Related Health Problems, Tenth Revision code L40.1) identified in Optum deidentified EHR data between July 1, 2015, and June 30, 2020. The index GPP diagnosis was the first occurrence in the EHR, with no coded history of GPP for at least 6 months prior. Flare episodes were identified using an algorithm based on diagnosis coding, care setting, type of clinician, GPP disease terms, and flare terms and attributes in the EHR.

Main Outcomes and Measures

Flare episodes were characterized by the frequency of occurrence per patient, the care setting in which they were identified, the type of specialist managing the episode, associated symptoms, and the type of treatment before, during, and after the episode. Patients were divided into groups based on whether or not they had a flare episode documented in their EHR. Comparisons were made between the groups based on demographic characteristics, comorbidity burden, health care use, and treatments.

Results

Of 1535 patients with GPP (1018 women [66.3%]; mean [SD] age, 53.4 [14.7] years), 271 had 513 flares documented. Compared with patients without flares, patients with flares had a 34% higher mean (SD) Charlson Comorbidity Index score (2.80 [3.11] vs 2.09 [2.52]), were almost 3 times more likely to have inpatient visits (119 of 271 [44%] vs 194 of 1264 [15%]), were more than twice as likely to have emergency department (ED) visits (126 of 271 [47%] vs 299 of 1264 [24%]), and had higher use of almost all treatment classes. Flares were identified in outpatient (271 of 513 [53%]), inpatient (186 of 513 [36%]), and ED (48 of 513 [9%]) settings. The most common treatments during flares were topical corticosteroids (35% of episodes [178 of 513]), opioids (21% [106 of 513]), other oral treatments, (eg, methotrexate, cyclosporine, tacrolimus; 13% [67 of 513]), and oral corticosteroids (11% [54 of 513]). Almost one-fourth of flare episodes (24% [122 of 513]) had no dermatologic treatment 30 days before, during, or 30 days after a flare episode.

Conclusions and Relevance

This cohort study suggests that there is significant unmet need for the treatment of GPP and its flares, as evidenced by patients seeking treatment in inpatient and ED settings, as well as the lack of advanced treatments.

Generalized Pustular Psoriasis in Pregnancy: Current and Future Treatments

Generalized pustular psoriasis (GPP) is a rare, severe neutrophilic skin disease characterized by sudden widespread eruption of sterile pustules with or without systemic symptoms. GPP may be life threatening in cases with severe complications such as cardiovascular failure, acute respiratory distress syndrome, and serious infections. Impetigo herpetiformis (IH) is a GPP that is induced and exacerbated by pregnancy and occurs most frequently during the last trimester. IH may result in poor or fatal neonatal outcomes, including placental insufficiency, fetal abnormalities, stillbirth, and early neonatal death. Most patients have prompt remission in the postpartum period; however, earlier appearance and more severe symptoms are observed during subsequent pregnancies. Appropriate treatment and close monitoring of the mother and fetus are vital for the management of patients with IH. Particular attention is required for the management of patients with IH to avoid an influence on the fetus. However, data regarding treatments for GPP in pregnant women are sparse. Over the last decade, many patients with IH have been treated with cyclosporine, corticosteroids, tumor necrosis factor-α inhibitors, interleukin (IL)-17 and IL-12/23 inhibitors, and granulocyte and monocyte adsorption apheresis (GMA). GMA may be an important option for patients with IH as it is presently one of the safest available therapeutic options, but there have been no reports to fully confirm its safety in pregnant patients with GPP. Alternatively, based on recent advances in the understanding of the role of the IL-36 axis in the pathogenesis of GPP, biologic agents that target the IL-36 pathway may demonstrate promising efficacy in IH.

Generalized pustular psoriasis (von Zumbusch)

Generalized pustular psoriasis (von Zumbusch) is a rare and acute eruption characterized by multiple sterile pustules over an erythematous and edematous background, eventually associated with psoriasis vulgaris. Classically, it manifests as a potentially severe systemic picture and demands prompt diagnosis and intervention. The duration of each flare-up and intervals between the pustular episodes is extremely variable. Recently, genetic abnormalities have been identified mainly in the familial and early variants of this disease. The therapeutic arsenal is limited; however, new drugs being evaluated aim to control both pustular flare-ups and disease recurrences.

Pustular Psoriasis: From Pathophysiology to Treatment

Pustular psoriasis (PP) is a clinicopathological entity encompassing different variants, i.e., acute generalized PP (GPP), PP of pregnancy (impetigo herpetiformis), annular (and circinate) PP, infantile/juvenile PP, palmoplantar PP/palmoplantar pustulosis, and acrodermatitis continua of Hallopeau (ACH), which have in common an eruption of superficial sterile pustules on an erythematous base. Unlike psoriasis vulgaris, in which a key role is played by the adaptive immune system and interleukin (IL)-17/IL-23 axis, PP seems to be characterized by an intense inflammatory response resulting from innate immunity hyperactivation, with prominent involvement of the IL-36 axis. Some nosological aspects of PP are still controversial and debated. Moreover, owing to the rarity and heterogeneity of PP forms, data on prognosis and therapeutic management are limited. Recent progresses in the identification of genetic mutations and immunological mechanisms have promoted a better understanding of PP pathogenesis and might have important consequences on diagnostic refinement and treatment. In this narrative review, current findings in the pathogenesis, classification, clinical features, and therapeutic management of PP are briefly discussed.

State-of-the-Art Review of Pregnancy-Related Psoriasis

Psoriasis is a chronic immunologic disease involving inflammation that can target internal organs, the skin, and joints. The peak incidence occurs between the age of 30 and 40 years, which overlaps with the typical reproductive period of women. Because of comorbidities that can accompany psoriasis, including metabolic syndrome, cardiovascular involvement, and major depressive disorders, the condition is a complex one. The role of hormones during pregnancy in the lesion dynamics of psoriasis is unclear, and it is important to resolve the implications of this pathology during pregnancy are. Furthermore, treating pregnant women who have psoriasis represents a challenge as most drugs generally prescribed for this pathology are contraindicated in pregnancy because of teratogenic effects. This review covers the state of the art in psoriasis associated with pregnancy. Careful pregnancy monitoring in moderate-to-severe psoriasis vulgaris is required given the high risk of related complications in pregnancy, including pregnancy-induced hypertensive disorders, low birth weight for gestational age, and gestational diabetes. Topical corticosteroids are safe during pregnancy but effective only for localised forms of psoriasis. Monoclonal antibodies targeting cytokines specifically upregulated in psoriasis, such as ustekinumab (IL-12/23 inhibitor), secukinumab (IL-17 inhibitor) can be effective for the severe form of psoriasis during pregnancy. A multidisciplinary team must choose optimal treatment, taking into account fetal and maternal risks and benefits.

Similarity and difference between palmoplantar pustulosis and pustular psoriasis

Palmoplantar pustulosis is a chronic inflammatory disorder characterized by sterile pustules predominantly involving the palms and soles. Palmoplantar pustulosis has many similar aspects to psoriasis, either plaque and pustular type, namely familial occurrence between palmoplantar pustulosis and psoriasis, the appearance of the Köbner phenomenon, joint involvement, and nail involvement. Pustular psoriasis is classified into generalized and localized types, and there are a number of papers regarding palmoplantar pustulosis as an acral variant of localized pustular psoriasis. Many Japanese dermatologists consider palmoplantar pustulosis to be a distinct entity from pustular psoriasis, and the coexistence of palmoplantar pustulosis and psoriasis is rare. However, outside Japan, palmoplantar pustulosis is often considered to be palmoplantar psoriasis or palmoplantar pustular psoriasis, and extra-palmoplantar lesions are also considered to be psoriasis. The purpose of the current review is to compare the similarities and differences between palmoplantar pustulosis and generalized/localized pustular psoriasis. Japanese patients with palmoplantar pustulosis have a close relationship with focal infection, and the associated bone-joint manifestation exclusively involves the anterior chest wall. Furthermore, pediatric occurrence of palmoplantar pustulosis is extremely rare, and difference of genetic background between palmoplantar pustulosis and psoriasis has also been reported. Treatment of focal infection often results in dramatic effects on both cutaneous lesions and joint pain of palmoplantar pustulosis. Those findings suggest that palmoplantar pustulosis should be separately considered from either palmoplantar psoriasis or palmoplantar pustular psoriasis. The clinicopathological features and therapeutic approach of both diseases are discussed.