AMPK activation modulates IL-36-induced inflammatory responses by regulating IκBζ expression in the skin

BACKGROUND AND PURPOSE

The interleukin (IL)-36 pathway is a critical player in the pathogenesis of pustular psoriasis. However, therapies targeting this pathway are limited or unaffordable (e.g. the anti-IL-36 receptor antibody). AMP-activated protein kinase (AMPK), a regulator of cellular energy and metabolism, is known to participate in inflammatory diseases. However, its role in IL-36-induced skin inflammation remains unclear. Therefore, we sought to investigate the role of AMPK signals in regulating IL-36-induced responses in the skin.

EXPERIMENTAL APPROACH

IL-36-stimulated primary normal human epidermal keratinocytes (NHEKs) and IL-36-injected (intradermally) BALB/c mice served as the cell and animal models, respectively. Additionally, 5-aminoimidazole-4-carboxamide riboside (AICAR) and A769662 served as AMPK activators.

KEY RESULTS

AICAR and A769662 significantly suppressed the IL-36-induced IL-8 (CXCL8) and CCL20 production from NHEKs. IL-36-induced IκBζ protein expression was prominently reduced and IKK/IκBα phosphorylation was attenuated by AICAR and A769662. Conversely, AMPKα knockdown increased IκBζ protein expression and IKK/IκBα phosphorylation in IL-36-treated NHEKs. Furthermore, AICAR and A769662 enhanced IL-36-induced-IκBζ protein degradation via the proteasome-dependent but not the lysosome-dependent pathway. Pretreatment of NHEKs with IL-36 slightly suppressed the AICAR- and A769662-triggered phosphorylation of AMPK and acetyl-CoA carboxylase. In the mouse model, topical application of AICAR significantly reduced ear swelling, redness, epidermal thickening, neutrophil infiltration and inflammatory and antimicrobial peptide gene expression.

CONCLUSION AND IMPLICATIONS

AMPK activation suppresses IL-36-induced IL-8 and CCL20 release by regulating IκBζ expression in keratinocytes and reduces IL-36-induced skin inflammation in mice, suggesting that AMPK activation is a potential strategy for treating patients with IL-36-mediated inflammatory skin disorders.

Therapeutic Potential of Spesolimab-Sbzo in the Management of Generalized Pustular Psoriasis Flares in Adults: Evidence to Date

Generalized pustular psoriasis (GPP) is a rare, chronic, and severe skin disorder characterized by the eruption of non-infectious pustules on an erythematous background often associated with systemic symptoms. It may appear in association with plaque psoriasis or occur in previously healthy individuals. It differs from psoriasis vulgaris in clinical presentation, immunopathogenesis, histology, and therapeutic strategies. Overexpression of interleukin 36 (IL-36) or a loss-of-function mutation of IL-36 receptor antagonist (IL-36RA) are thought to play a pivotal role in the pathogenesis of this disease. There are currently no globally approved guidelines for the treatment of GPP, and the therapies used so far, with variable results, have given unsatisfactory results. Spesolimab, a selective humanized antibody against the IL-36 receptor that blocks its activation, is the first biologic drug approved in Europe in December 2022 for the treatment of GPP flares. It represents a promising therapy, demonstrating efficacy in reducing disease severity and improving patient outcomes. In our review, we have analyzed the latest advancements and findings regarding the efficacy and safety of spesolimab in the context of GPP management.

Pediatric psoriasis: Understanding pathological conditions and advances in treatment

Psoriasis is a long-lasting skin disease that primarily affects the skin, nails, and joints and is characterized by inflammation. Genetic factors contribute to its development and environmental triggers can worsen symptoms. Pathologically, psoriasis is characterized by uncontrolled keratinocyte proliferation and abnormal differentiation, and histological features include acanthosis with inflammatory cell infiltration and neovascularization. Psoriasis often starts in childhood, with about one-third of cases beginning during this time. Its prevalence steadily increases from the ages of 1 to 18 years in a linear fashion. Young people with psoriasis often require treatment throughout their childhood and adolescence, and into adulthood. However, prolonged treatment may increase the risk of complications and adverse events, so it is important to adopt an effective treatment approach that minimizes this risk. In addition, psoriasis is often associated with various comorbidities that may place a great burden on the physical and mental health of the children beyond those due to psoriasis itself. To ensure good long-term health outcomes, individuals with psoriasis should undergo regular screening. Treatment should be provided not only for skin lesions, but also for any comorbidities; however, currently there is not enough evidence on the treatment of pediatric psoriasis and no globally agreed-on guidelines exist for treating psoriasis in children. This article describes the etiology, clinical symptoms, and disease burden of pediatric psoriasis, the pathological conditions and diagnosis of plaque psoriasis, psoriatic arthritis, and generalized pustular psoriasis, and the available treatments for these conditions in Japan.

Diseases categorized as autoinflammatory keratinization diseases (AiKDs), and their pathologies and treatments

Whole-exome and whole-genome sequencing have become widespread in approximately the last 15 years, and the predisposing factors and pathomechanisms of inflammatory keratinization diseases, which have been unknown for a long time, have gradually been revealed. Hence, various inflammatory keratinization diseases are recognized to cause innate immunity hyperactivation. Therefore, we have been advocating for the clinical entity, "autoinflammatory keratinization diseases (AiKDs)" since 2017. AiKDs are inflammatory keratinization diseases caused by autoinflammatory-related pathomechanisms in the skin. The aberrant activation of innate immunity and the resultant autoinflammation in the epidermis and the superficial dermis in AiKDs cause hyperkeratosis in the epidermis. Our initially proposed concept of AiKDs included generalized pustular psoriasis and related conditions, pityriasis rubra pilaris type V, and familial keratosis lichenoides chronica. Since then, the number of diseases known to be AiKDs has increased as previously unknown disease-causing factors and pathogenetic mechanisms of inflammatory keratinization diseases have been clarified one by one. To date, porokeratosis, hidradenitis suppurative, keratosis linearis with ichthyosis congenita and sclerosing keratoderma (KLICK) syndrome, and AiKDs associated with epidermal growth factor receptor (EGFR) deficiency or with hepatitis and autism have been recognized as AiKDs. The concept of AiKDs is considered extremely useful in our precise understanding of the pathogeneses behind inflammatory keratinization diseases and our appropriate treatment method selection. The number of AiKDs is expected to grow with the clarification of the pathomechanisms of further inflammatory keratinization diseases.

Clinical advances in biological therapy for generalized pustular psoriasis: a review

INTRODUCTION

In 2022, U.S. Food and Drug Administration (FDA) approved the first biologics, intravenous spesolimab, for acute flare of generalized pustular psoriasis (GPP). The drug works by blocking IL-36 signaling, the key pathway of GPP. Among the known mutations causing GPP, IL36RN mutations are most common, and the presence of IL36RN mutations had been found to affect the clinical manifestations and treatment response of GPP.

AREAS COVERED

Literature search was conducted in PubMed, Embase and ClinicalTrials.gov for relevant studies discussing biologic treatment for GPP with special emphasis on larger studies, pediatric group, pregnant women, and the influence of IL36RN mutation on the effectiveness of biologics.

EXPERT OPINION

The approval of spesolimab for GPP flare treatment marks a new era. However, whether spesolimab will be placed as the treatment of choice remains unknown, considering its higher cost, lack of direct comparison with existing biologics, and uncertain effects on co-existing plaque-type psoriasis. However, the demonstration of numerically better efficacy for patients carrying pathogenic IL36RN mutations suggests the role of pharmacogenetics in the choices of GPP treatment. Future randomized studies are warranted to investigate the effectiveness and safety of biologics for GPP in pediatric and pregnant groups.

Concurrent Presentation of Pustular Psoriasis and Late-Onset Rheumatoid Arthritis: A Diagnostic Challenge in a Community Hospital Setting

The coexistence of autoimmune diseases presents a significant diagnostic challenge in clinical practice, particularly in settings with limited resources. This case report details a rare instance of pustular psoriasis occurring concurrently with rheumatoid arthritis, underscoring the complexities involved in diagnosing overlapping autoimmune disorders. A 70-year-old male with a history of chronic heart failure, atrial fibrillation, and other comorbidities presented to a rural community hospital with a year-long persistent rash and joint and back pain. Physical examination and blood tests revealed high inflammatory markers. A dermatological assessment, including a skin biopsy, diagnosed generalized pustular psoriasis. However, the atypical presentation of acute polyarthritis led to further investigations, revealing elevated rheumatoid factor and anti-citrullinated protein antibody levels, resulting in a diagnosis of late-onset rheumatoid arthritis. The patient underwent a comprehensive treatment regime, including prednisolone, cefazolin, oral terbinafine, methotrexate, and infliximab, leading to gradual symptom improvement to the previous activity of daily life and discharge on the 27th day of hospitalization. This case illustrates the diagnostic intricacies in identifying concurrent autoimmune disorders and highlights the crucial role of general physicians in systematically approaching complex cases in resource-limited settings. It emphasizes the need for heightened clinical vigilance and a multifaceted diagnostic approach when managing patients with overlapping rheumatic symptoms, advocating for consideration of coexisting conditions in autoimmune diseases.

Acrodermatitis continua of Hallopeau and generalised pustular psoriasis: Should they be the same or different entities?

Pustular psoriasis is characterised by eruptions of neutrophilic sterile pustules. The European Rare and Severe Psoriasis Expert Network consensus defines pustular psoriasis into three subtypes; generalised pustular psoriasis (GPP), palmoplantar pustulosis and acrodermatitis continua of Hallopeau (ACH). Mixed forms are categorised according to their predominant features. However, the Japanese Dermatological Association includes ACH under the diagnosis of GPP. This article aims to review the similarities and differences between ACH and GPP. Based on our review, interleukin (IL)-36RN mutations, the most frequent genetic findings in pustular psoriasis are found most commonly in GPP, followed by ACH. Genotypes of IL-36RN mutations among GPP patients and ACH patients are different between European and Asian ethnicities. IL-36 signalling pathway is the main mechanism. Metabolic diseases are common comorbidities and joint involvement can occur in 20.5%-36.4% of both conditions. Associated plaque psoriasis is more common in GPP than in ACH. Generally, ACH, even the generalised type, does not have systemic inflammation whereas GPP can occur with or without systemic inflammation. ACH can occur before, simultaneously, or after the development of GPP. However, response to treatment for GPP and ACH even in the same patients appear to be different. ACH seemed to be more recalcitrant to treatment than GPP but severe flare of GPP can lead to morbidity and mortality. Although GPP and ACH share genotypes and pathogenesis, we believe that ACH should be classified separately from GPP, and not under diagnosis of GPP. Future research is warranted to satisfactorily distinguish the two conditions.

Gastrointestinal and hepatic manifestations in patients with generalised pustular psoriasis

Generalised pustular psoriasis (GPP) is a rare and severe form of pustular psoriasis. It is defined by persisting or relapsing macroscopically visible sterile primary pustules occurring on non-acral skin and not within psoriasis plaques. Due to its rarity, there is a lack of randomised controlled trials on GPP and its associated gastrointestinal (GI) and liver disorders. In this article, we present a review of the GI and hepatic disorders associated with GPP. GPP is known to be associated with extracutaneous manifestations such as neutrophilic cholangitis. Abnormal liver function tests are reported in up to 90% of patients with GPP upon diagnosis. Less commonly, pancreatitis and gastrointestinal bleeding have been attributed to GPP. While a psoriasis registry with 7.5% prevalence of pustular psoriasis reported an association with viral hepatitis B and C, the true relationship remains to be elucidated as hepatitis B is endemic in Asia where GPP prevalence is higher. Common genetic mutations between GPP and conditions such as hepatocellular carcinoma and inflammatory bowel disease have been identified, explaining their possible associations and providing answers to potential therapeutic options for these conditions. A lack of recognition of these association may result in unnecessary withdrawal of efficacious and definitive drugs for the treatment of GPP. Understanding the characteristics of the associated GI and hepatic disorders will have important implications for targeting the appropriate therapeutics.

Generalized pustular psoriasis: Quality and readability of online health information

Generalized pustular psoriasis (GPP) is a multisystem disease with potentially life-threatening adverse effects. As patients increasingly seek health information online, and as the landscape for GPP changes, the quality of online health information (OHI) becomes progressively more important. This paper is the first of its kind to examine the quality, comprehensiveness and readability of online health information for GPP. Similar to pre-existing studies evaluating OHI, this paper examines 5 key search terms for GPP- 3 medical and 2 laymen. For each search term, the results were evaluated based on HONcode accreditation, an enhanced DISCERN analysis and a number of readability indices. Of the 500 websites evaluated, 84 (16.8%) were HONcode-accredited. Mean DISCERN scores of all websites were 74.9% and 38.6% for website reliability and treatment sections, respectively, demonstrating key gaps in comprehensiveness and reliability of GPP-specific OHI. Additionally, only 4/100 websites (4%) analysed for readability were written at the NIH-recommended sixth-grade level. Academic websites were significantly more difficult to read than governmental websites. This further exacerbates the patient information gap, particularly for patients with low health literacy, who may already be at higher risk of not receiving timely medical care.

A narrative review of studies assessing the quality of life in patients with generalized pustular psoriasis

Generalized pustular psoriasis (GPP) is a clinical entity distinct from psoriasis, associated with a poor clinical prognosis, often resulting in severe systemic complications and mortality. The relapsing nature of the disease with recurrent or intermittent flares imposes a significant burden on patients' quality of life (QoL). Although inadequately studied, QoL data in GPP patients has been a recent point of investigation. We conducted a literature search on PubMed/MEDLINE using the following search terms: 'generalized pustular psoriasis' OR 'pustular psoriasis' AND 'quality of life'. We identified 12 relevant articles that provide insight into the large impact of GPP on the QoL of patients, the burden of the disease and the treatment, and the success of new treatment options in making a clinically important difference to QoL. This review illustrates a need for routine assessment of the QoL in interventional clinical trials for GPP and during physician encounters. This information can help guide clinicians on how to tailor the treatment approach from the patient's perspective or illustrate whether new therapies offer meaningful benefits to patient care as we enter an era of exciting new treatments for this challenging condition.

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.

Pustular Eruption following COVID-19 Vaccination: A Narrative Case-Based Review

From the beginning of public vaccinations until the relaxation of COVID-19 measures, many case reports, case series and case-control studies have been published indicating cutaneous side effects of COVID-19 vaccination. Post-vaccination pustular eruption was reported as well, with a challenging differential diagnosis between pustular psoriasis, AGEP (acute generalized exanthematous pustulosis) and neutrophil pustular eruptions. We report a case of 56-year-old woman presented with acute generalized pustular flare up culminated 5 days after the second dose of BNT162b2(Pfizer) vaccination. She was diagnosed with pustular psoriasis flare and due to the regulating role of IL-1 in pustular psoriasis and in the cytokine storm observed in cases of COVID-19 postvaccination inflammation; we decided to treat the patient with an IL-1 antagonist, subcutaneous anakinra (100 mg daily) along with acitretin. One week later, after anakinra withdrawal, she presented a pustular psoriasis flare and a 7-day anakinra re-administration led to a satisfactory improvement in the skin lesions. We also reviewed the medical literature and found 28 case reports with pustular eruption after the COVID-19 vaccination. We compared the patients reported, regarding sex, age, number of doses, post-vaccination period and vaccine brand, and compared those results with our patient. Finally, as indicated by our case and other cases with similarly treated pustular eruptions. targeted therapy to this cytokine imbalance such as anakinra (IL-1) antagonist can improve the clinical course of the patient.

Brodalumab in the Treatment of Plaque Psoriasis Localized in Difficult-to-Treat Areas: A Narrative Review

INTRODUCTION

Psoriasis is a common chronic, immune-mediated, inflammatory skin disease that in certain localization results difficult to treat. Psoriatic lesions in difficult-to-treat areas might be hardly managed as no standardized therapeutic approach and the application of topical treatments might have great limitations. Systemic agents, including biologic therapies, have been proven effective in treating this subgroup of patients. In particular, current evidence has shown beneficial effects with the use of brodalumab, a fully human IgG2 monoclonal antibody antagonizing the IL-17 receptor A subunit (IL-17RA).

OBJECTIVES

The aim of this narrative review was to collect published data about efficacy and safety of brodalumab in the treatment of psoriasis occurring in difficult-to-treat areas.

METHODS

Data on brodalumab effectiveness and safety deriving from both trials and real-world setting that had been published in the last 15 years were collected for this review, together with clinical findings issued during international meetings.

RESULTS

In phase 3 trials, brodalumab demonstrated to be effective in promoting a rapid response in scalp psoriasis as well as in generalized pustular psoriasis and erythrodermic psoriasis. Nail psoriasis demonstrated marked clinical improvement after treatment with brodalumab. Amelioration of palmoplantar psoriasis was also described in brodalumab-treated patients. Various retrospective real-world studies reported a complete clearance of psoriatic lesions in difficult-to-treat areas, including genitalia, through short-term brodalumab treatment.

CONCLUSIONS

Brodalumab, combining rapid and sustained efficacy with a favorable safety profile, may be a valid therapeutic option for severe variants of psoriasis as well as for psoriasis localized in difficult-to-treat areas.

Rapid and sustained improvements in Generalized Pustular Psoriasis Physician Global Assessment scores with spesolimab for treatment of generalized pustular psoriasis flares in the randomized, placebo-controlled Effisayil 1 study

BACKGROUND

Effisayil 1 was a randomized, placebo-controlled study of spesolimab, which is an anti-IL-36 receptor antibody, in patients presenting with a generalized pustular psoriasis flare.

OBJECTIVE

To assess the effects of spesolimab over the 12-week study.

METHODS

The primary endpoint of the study was Generalized Pustular Psoriasis Physician Global Assessment (GPPGA) pustulation subscore of 0 at week 1. Patients (N = 53) were randomized (2:1) to receive a single intravenous dose of 900 mg spesolimab or placebo on day 1. Patients could receive open-label spesolimab for persistent flare symptoms on day 8.

RESULTS

Most patients receiving spesolimab achieved a GPPGA pustulation subscore of 0 (60.0%) and GPPGA total score of 0 or 1 (60.0%) by week 12. In patients randomized to placebo who received open-label spesolimab on day 8, the proportion with GPPGA pustulation subscore of 0 increased from 5.6% at day 8 to 83.3% at week 2. No factors predictive of spesolimab response were identified in patient demographics or clinical characteristics.

LIMITATIONS

The effect of initial randomization was not determined conventionally beyond week 1 due to patients receiving open-label spesolimab.

CONCLUSION

Rapid control of generalized pustular psoriasis flare symptoms with spesolimab was sustained over 12 weeks, further supporting its potential use as a therapeutic option for patients.

Efficacy and safety of spesolimab for the management of generalized pustular psoriasis: a drug safety evaluation

INTRODUCTION

Generalized pustular psoriasis (GPP) is a rare form of psoriasis (less of 1% of cases). Currently, GPP is recognized as a clinical entity, distinguished from plaque psoriasis. However, there are not guidelines for GPP management and treatments are often derived from plaque psoriasis. Therefore, conventional systemic drugs are usually used as first-line treatment options, and biologics are still used off label. Recently, spesolimab, an anti-IL36 receptor humanized IgG1 monoclonal antibody, has been specifically approved for GPP disease, revolutionizing treatment scenario.

AREAS COVERED

The aim of this review is to investigate current literature on the use of spesolimab for GPP management to underline its potential role in GPP and offer a current clinical perspective. Literature research using the Google Scholar, Pubmed, Embase, Cochrane Skin, and clinicaltrials.gov databases was performed, selecting the most relevant manuscripts.

EXPERT OPINION

Spesolimab is efficacious and has a consistent and favorable safety profile in patients presenting with a GPP flare. However, despite excellent results in terms of safety and efficacy have been reported by both clinical trials and very limited real-life experiences, long-term data, especially in flare-up prevention, are scant. Thus, while the available data are encouraging, further research is warranted to understand the efficacy, safety, and long-term outcomes associated with spesolimab treatment in GPP.

Hydroxychloroquine-induced repetitive atypical pustular drug eruptions in the same patient separated by 12 years

Hydroxychloroquine (HCQ) has been reported to cause pustular drug eruptions such as acute generalized exanthematous pustulosis (AGEP) and putular psoriasis (PP). Clinical differentitation of these entities is often difficult. This case emphasizes characteritics of AGEP and PP as well as the need for clinicans to proactively follow-up these patients to monitor for the more aggressive outcome of PP.

Use of Biological Therapies for the Management of Pustular Psoriasis: A New Era?

Generalized pustular psoriasis (GPP) is a severe and rare form of psoriasis, being a potentially life-threatening condition, characterized by recurring episodes or flares of widespread cutaneous erythema with macroscopic sterile pustules. An irregular innate immune response is linked to GPP, which is considered an auto-inflammatory disorder, while innate and adaptive immunopathogenic responses are involved in psoriasis pathogenesis. In consequence, different cytokine cascades have been suggested to be mainly involved in the pathogenesis of each different psoriasis form, with the interleukin (IL)23/IL17 axis implied in plaque psoriasis, and the IL36 pathway in the GPP. As regards GPP treatment, conventional systemic drugs available for plaque psoriasis are usually used as the first-line treatment option. However, contraindications and adverse events often limit the use of these therapies. In this scenario, biologic drugs may represent a promising treatment option. To date, even if 12 different biologics have been approved for plaque psoriasis, none of these is approved for GPP where they are employed off-label. Recently, spesolimab, an anti-IL36 receptor monoclonal antibody, has been recently approved for GPP. The purpose of this article is to assess the current literature about the use of biological therapies for the treatment of GPP to establish the basis for a shared GPP management algorithm.

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.

Pyoderma gangrenosum following anti-TNF therapy in chronic recurrent multifocal osteomyelitis: drug reaction or cutaneous manifestation of the disease? A critical review on the topic with an emblematic case report

Chronic recurrent multifocal osteomyelitis (CRMO) is a rare autoinflammatory disease, clinically characterized by chronic and recurrent episodes of osteoarticular inflammation, that generally presents in children and adolescents. From a dermatological point-of-view, CMRO can be associated with skin rashes mainly including psoriasis, palmoplantar pustulosis and acne. Pyoderma gangrenosum (PG) is a rare immune-mediated inflammatory skin disease classified within the spectrum of neutrophilic dermatoses that, in some cases, has been reported as cutaneous manifestation in CMRO patients. This paper presents a 16-year female patient diagnosed with CMRO, who presented PG lesions located on the lower leg, that arose after the administration of the tumour necrosis factor (TNF)-α inhibitor adalimumab. Cases of PG have been reported in patients being treated with certain medications, including TNF-α antagonists, leading to classified them in a setting aptly termed "drug-induced PG." In this paper, we discuss the co-occurrence of PG and CRMO, in the light of recent evidence on the pathogenesis of both diseases and giving ample space to a literature review on drug induced PG. In our case, it is plausible that PG could be considered a cutaneous manifestation of CRMO, although the mechanisms underlying this intriguingly relationship remain to be fully unraveled.

Acrodermatitis continua of Hallopeau successfully treated with bimekizumab: A case report

Acrodermatitis continua of Hallopeau is a rare variant of localized pustular psoriasis characterized by the recurrent eruption of sterile pustules involving the distal portions of the fingers and toes that can lead to the destruction of the nail apparatus. Acrodermatitis continua of Hallopeau is a chronic, relapsing condition that is resistant to most topical and systemic psoriasis therapies, making it notoriously difficult to manage. Interleukin-36 and interleukin-17 are thought to play a pivotal role in the pathophysiology of pustular psoriasis, and evidence suggests that interleukin-17 inhibition can be an effective therapy for pustular psoriasis variants, including acrodermatitis continua of Hallopeau. Bimekizumab, a monoclonal antibody that inhibits the interleukin-17 pathway, may be a safe and effective treatment option for patients with acrodermatitis continua of Hallopeau. We present the first documented case of a patient with acrodermatitis continua of Hallopeau of the bilateral thumbnails who experienced an excellent response to bimekizumab treatment.

Interleukin-17 vs. Interleukin-23 Inhibitors in Pustular and Erythrodermic Psoriasis: A Retrospective, Multicentre Cohort Study

Pustular and erythrodermic psoriasis are rare and difficult-to-treat conditions. It has recently been shown that interleukin (IL)-17 inhibitors can be very effective among patients with these forms of psoriasis; however, the potential of IL-23 inhibitors is largely unknown. The aim of this multicentre, retrospective study was to compare the safety, effectiveness, and drug survival of IL-17 and IL-23 inhibitors among patients affected by these rare forms of psoriasis. The study involved 27 patients with erythrodermic psoriasis and 59 with pustular psoriasis (36 with generalised pustular psoriasis and 23 with palmoplantar pustular psoriasis) treated with an IL-17 or IL-23 inhibitor. The effectiveness of the two drug classes was assessed using the disease-specific Psoriasis Area Severity Index (PASI) and the Investigator Global Assessment, which were evaluated at different time points. There was a consistent trend towards a higher rate of PASI 100 responses in the patients treated with IL-17 inhibitors compared with those treated with IL-23 inhibitors, and the other efficacy outcomes showed a similar trend. There was no significant between-drug class difference in efficacy at any of the time points in the erythrodermic psoriasis cohort, whereas PASI 90 and PASI 100 response rates were significantly higher among the pustular psoriasis patients receiving IL-17 inhibitors at week 12 (IL-23 19% vs. IL-17 54% and IL-23 6% vs. IL-17 40%, respectively) and the percentage of responders to IL-17 inhibition was significantly higher at week 24 (IL-23 25% vs. IL-17 74%). In conclusion, it is therefore reasonable to assume that IL-17 and IL-23 inhibitors are both effective when treating pustular and erythrodermic psoriasis.

Distinguishing annular pustular psoriasis from subcorneal pustular dermatosis-A diagnostic dilemma in a 10-year-old boy

Subcorneal pustular dermatosis (SPD) and annular pustular psoriasis (APP) are very rare in childhood and difficult to differentiate both clinically and histopathologically. We report the case of a 10-year-old male with a 9-year history of erythematous scaly annular plaques with scattered pustules on the trunk. Although initially diagnosed as SPD, a lack of response to dapsone, presence of spongiosis on histology, and early age of disease onset led to consideration of APP. The patient was subsequently treated with adalimumab 80 mg weekly and completely cleared. This case illustrates the overlapping features of SPD and APP and suggests that the two disorders may represent a spectrum of the same disease.

Epidemiological survey of patients with pustular psoriasis in the Japanese Society for Psoriasis Research from 2017 to 2020

The Japanese Society for Psoriasis Research (JSPR) has been conducting annual epidemiological surveys of patients with pustular psoriasis in Japan since 2017. This study aimed to conduct a recent epidemiological analysis of patients with pustular psoriasis who were enrolled in the JSPR from 2017 to 2020. A total of 291 patients from 131 medical institutions were enrolled, of which 47.4% (138 cases) were males and 52.6% (153 cases) were females. The mean ± standard deviation (SD) age of the patients was 57.4 ± 20.3 years (males, 61.2 ± 17.3 years; females, 54.1 ± 22.1 years). The mean ± SD age of the patients at disease onset was 48.5 ± 22.5 years (males, 50.8 ± 20.6 years; females, 46.4 ± 24.0 years). The types of pustular psoriasis observed included the von Zumbusch type (59.8%), annular pustular psoriasis (8.2%), impetigo herpetiformis (6.5%), and acrodermatitis continua of Hallopeau (4.8%), of which, the majority of the patients with impetigo herpetiformis were female. Among the patients, 58.4% were treated with oral medications and 44.0% were treated with biologics. The most common oral medication prescribed was etretinate (52.4%), followed by corticosteroids (24.7%) and cyclosporin (22.9%). The most common biologics used were IL-17 inhibitors (ixekizumab [28.1%] and secukinumab [22.7%]), followed by tumor necrosis factor (TNF) inhibitors (infliximab [15.6%]) and IL-23 inhibitors (guselkumab [14.8%] and risankizumab [10.2%]). This survey thus provides new and significant information regarding the recent perspective of pustular psoriasis, such as patient characteristics and treatment trends, in Japan.

Targeting IL-17A for the treatment of pustular psoriasis: a comprehensive review

INTRODUCTION

Pustular psoriasis (PP) is a rare subtype of psoriasis. Overall, the growing evidence - in particular for acute generalized PP (GPP) - supports that it is a separate entity with a specific pathogenetic pathway. Interleukin (IL)-17/T-helper 17 (Th17) axis involvement may play an important role in the pathophysiology of PP. Biologicals, often required to achieve clinical remission, have changed the treatment of PP.

AREAS COVERED

We provide the reader with an overview of all the available evidence on the use of the antibody-based therapy targeting IL-17A in patients with PP.

EXPERT OPINION

Although papers reported in this review do not provide definitive evidence (due to methodological limitations) to support the use of IL-17 inhibitors as potential first-line for the treatment of PP, based on our own experience and according to most of the reported literature, targeting IL-17A, may represent the best therapeutical approach in this peculiar clinical spectrum of psoriasis.

IL-1 Family Cytokines in Inflammatory Dermatoses: Pathogenetic Role and Potential Therapeutic Implications

The interleukin-1 (IL-1) family is involved in the correct functioning and regulation of the innate immune system, linking innate and adaptative immune responses. This complex family is composed by several cytokines, receptors, and co-receptors, all working in a balanced way to maintain homeostasis. Dysregulation of these processes results in tissue inflammation and is involved in the pathogenesis of common inflammatory dermatoses such as psoriasis, hidradenitis suppurativa, and atopic dermatitis. Therefore, therapeutic targeting of IL-1 pathways has been studied, and several monoclonal antibodies are currently being assessed in clinical trials. So far, promising results have been obtained with anti-IL-36R spesolimab and imsidolimab in pustular psoriasis, and their efficacy is being tested in other conditions.

Clinical Characteristics of Patients with Pustular Psoriasis: A Single-Center Retrospective Observational Study

Clinical and epidemiologic data on pustular psoriasis are scarce. To investigate the phenotypes of pustular psoriasis and the patients’ characteristics observed in a real-life retrospective observational study. The number of incident cases of pustular psoriasis registered in the period 2005–2021 was retrieved from the electronic medical records of the University Hospital of Verona. One hundred and forty cases of pustular psoriasis were collected. Ninety-one out of 140 patients (65%) were females, with a median (IQR) age of 57 (43–66) years. According to the ERASPEN classification criteria, 116 patients (83%) had palmoplantar pustulosis (PPP), 13 (9%) generalized pustular psoriasis (GPP), and 11 (8%) acrodermatitis continua of Hallopeau (ACH). Gender distribution and median age were consistent among the three groups. The prevalence of psoriatic arthritis in GPP, ACH, and PPP was 8%, 36%, and 28%, respectively. During the same period, a total of 4718 cases of plaque psoriasis were retrieved, with a 1:34 ratio of pustular over plaque psoriasis. Pustular psoriasis is much rarer than plaque psoriasis, with PPP being the more common subtype.

Flare-up of generalized pustular psoriasis combined with systemic capillary leak syndrome after coronavirus disease 2019 mRNA vaccination

Generalized pustular psoriasis (GPP) is characterized by acute flare-ups induced by various factors, but few reports have described GPP onset or flare-up induced by vaccination. To our knowledge, only three such cases following coronavirus disease 2019 (COVID-19) vaccination have been reported. We herein report a case of GPP flare-up after COVID-19 mRNA vaccination. A 65-year-old man with GPP controlled by infliximab presented with widespread pustular erythema, fever, and malaise following his second COVID-19 mRNA vaccination. A skin eruption was apparent at the injection site. He also exhibited systemic capillary leak syndrome (SCLS), which responded rapidly to secukinumab and systemic corticosteroids. Two biopsies, one of which was of the injection site, revealed not only findings typical of GPP, but also a dermal mixed-cell infiltration with eosinophils, and microthrombi in the small dermal vessels. The latter findings have been observed in cutaneous lesions induced by both COVID-19 infection and vaccination. This is the first case of a GPP flare-up accompanied by SCLS induced by a COVID-19 mRNA vaccine. Also, this is the first flare-up induced by the second vaccine dose, and the first such report including detailed histological data, including for the injection site.

Severe de novo pustular psoriasiform immune-related adverse event associated with nivolumab treatment for metastatic esophageal adenocarcinoma

Breakthrough targeted therapies have produced significant improvements in survival for cancer patients, but have a propensity to cause cutaneous immune-related adverse events (irAEs). Psoriasiform irAEs, representing about 4% of dermatologic toxicities associated with immune checkpoint inhibitor (ICI) therapy, are usually mild, occur in older patients and present as an exacerbation of existing psoriasis after several doses of ICI therapy. We report a case of a 58-year-old woman with metastatic esophageal adenocarcinoma and no prior history of psoriasis who developed a pustular psoriasiform irAE, beginning 3 days after initiation of nivolumab and progressing to confluent erythroderma with pustules over 2 weeks despite topical steroid use. She had concurrent acrodermatitis enteropathica, clinically diagnosed and confirmed with a low serum zinc level, that improved with supplementation. Her psoriasiform irAE was refractory to systemic steroids and acitretin, prompting discontinuation of nivolumab and treatment with ustekinumab and concomitant slow taper of acitretin and prednisone. Pustular psoriasiform irAE is a rare but severe dermatologic toxicity resulting from ICI therapy. Given the diverse morphologic types of cutaneous irAEs that can occur during ICI therapy, a clinical and histopathologic examination of dermatologic toxicities is critical to identify patients who may benefit from biologic therapy.

The Cytokine Mediated Molecular Pathophysiology of Psoriasis and Its Clinical Implications

Psoriasis is the result of uncontrolled keratinocyte proliferation, and its pathogenesis involves the dysregulation of the immune system. The interplay among cytokines released by dendritic, T_h1, T_h2, and T_h17 cells leads to the phenotypical manifestations seen in psoriasis. Biological therapies target the cytokine-mediated pathogenesis of psoriasis and have improved patient quality of life. This review will describe the underlying molecular pathophysiology and biologics used to treat psoriasis. A review of the literature was conducted using the PubMed and Google Scholar repositories to investigate the molecular pathogenesis, clinical presentation, and current therapeutics in psoriasis. Plaque psoriasis', the most prevalent subtype of psoriasis, pathogenesis primarily involves cytokines TNF-α, IL-17, and IL-23. Pustular psoriasis', an uncommon variant, pathogenesis involves a mutation in IL-36RN. Currently, biological therapeutics targeted at TNF-α, IL-12/IL-23, IL-17, and IL-23/IL-39 are approved for the treatment of moderate to severe psoriasis. More studies need to be performed to elucidate the precise molecular pathology and assess efficacy between biological therapies for psoriasis. Psoriasis is a heterogenous, chronic, systemic inflammatory disease that presents in the skin with multiple types. Recognizing and understanding the underlying molecular pathways and biological therapeutics to treat psoriasis is important in treating this common disease.

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.

Clinical characteristics of Japanese pustular psoriasis: A multicenter observational study

Generalized pustular psoriasis (GPP) is a rare and severe subtype of psoriasis. Because of its rarity, GPP studies with a large sample size have been scarce. We studied the characteristics of GPP and pustular psoriasis using data from the West Japan Psoriasis Registry that had been registered until the end of December 2020. The dataset included 104 patients with pustular psoriasis and 1290 patients with other subtypes of psoriasis. Multivariate analysis revealed a significantly greater number of female patients, a significantly lower mean body mass index, and a significantly lower ratio of habitual drinkers in pustular psoriasis, compared to other subtypes of psoriasis. Of the 104 patients, 102 had GPP, including 88 von Zumbusch, 10 juvenile-onset, and four annular pustular psoriasis. Although the male : female ratio of GPP with psoriasis vulgaris (GPP+PsV) (47/20) was similar to that of psoriasis in Japan, the GPP without PsV (GPP-PsV) group highlighted a female predominance (13/22). The mean age at GPP onset was 45.3 years, and the mean interval from PsV onset to GPP onset was 12.5 years. Four of nine patients with GPP had an IL36RN gene mutation. Infection, medicine, and pregnancy were the precipitating factors for GPP. A family history of psoriasis was present in eight (7.8%) patients with GPP. Twenty-four patients with GPP had psoriatic arthritis. Biologics were used in 76.5% of patients with GPP, followed by etretinate (37.3%), cyclosporine (24.5%), methotrexate (13.7%), apremilast (8.8%), and granulocyte and monocyte adsorption apheresis (6.9%). Etretinate was used in 17 (51.5%) of 33 patients with GPP with less than 10-year history. Thus, etretinate remains a good treatment option for GPP even in the era of biologics. Hypertension was the most commonly identified comorbidity, followed by diabetes. We believe that the characteristics revealed in this study can further contribute to effective GPP management.

Update on the aetiology and mechanisms of generalized pustular psoriasis

Generalized pustular psoriasis (GPP) is a chronic disease characterized by non-bacterial pustules. Variants in several genes, such as IL36RN, AP1S3, and CARD14, are involved in the pathogenesis of GPP. The prevalence of different gene variants varies among ethnicities, and some variants are related to concurrent psoriasis vulgaris or age at onset. Flares can be triggered by medications (most commonly corticosteroids), infections (possibly due to Toll-like receptor [TLR] and antimicrobial peptides), pregnancy (the onset of GPP has been attributed to endocrine abnormalities such as hypoparathyroidism and hypocalcaemia), hypocalcaemia (presumably due to low levels of calcium and vitamin D regulating the proliferation and differentiation of keratinocytes), and other factors including stress and sun exposure. The mechanisms of pustule formation involve: 1) the LL37/TLR pathway, in which LL37 acts as an alarmin, interacting with TLR and activating the NF-κB and MAPK pathways; 2) the balance between calcium and 1,25(OH)2D levels, and 3) neutrophils and the complement system.

Pustular Psoriasis and Acute Generalized Exanthematous Pustulosis

The similarity between pustular psoriasis (PP) and acute generalized exanthematous pustulosis (AGEP) poses problems in the diagnosis and treatment of these two conditions. Significant clinical and histopathologic overlap exists between PP and AGEP. PP is an inflammatory disorder that has numerous clinical subtypes, but all with sterile pustules composed of neutrophils. AGEP is a severe cutaneous adverse reaction that is also characterized by non-follicular sterile pustules. Clinical features that suggest a diagnosis of PP over AGEP include a history of psoriasis and the presence of scaling plaques. Histologically, eosinophilic spongiosis, vacuolar interface dermatitis, and dermal eosinophilia favor a diagnosis of AGEP over PP. Importantly, PP and AGEP vary in clinical course and treatment. PP treatment involves topical steroids, oral retinoids, and systemic immunosuppressants. Newer therapies targeting IL-36, IL-23, IL-1, and PDE-4 have been investigated. The removal of the offending agent is a crucial part of the treatment of AGEP.

Epidemiology and clinical features of pustular psoriasis: A 15-year retrospective cohort

Pustular psoriasis (PuP) is a rare variant of psoriasis with a unique immunopathogenesis, unlike its more prevalent plaque-type counterpart. However, data available are limited due to its low prevalence. This study aimed to describe the demographic profile, precipitating factors, clinical presentations, and treatments among patients with different PuP subtypes from a 15-year retrospective cohort study in Thailand. A total of 60 patients were included in this study. There was female predominance (73.3%) and mean age of onset was 38.1 ± 17.6 years. Generalized PuP (GPP) was the most prevalent subtype (80.0%), followed by acrodermatitis continua of Hallopeau (13.3%) and palmoplantar pustulosis (6.7%). Precipitating factors included corticosteroid withdrawal, upper respiratory tract infection, and pregnancy. One-third of PuP occurred concomitantly with other psoriasis variants, especially the plaque type. The most prescribed systemic and topical treatments were oral acitretin (60.0%) and topical corticosteroids (98.3%), respectively. Only two patients were treated with narrow-band ultraviolet B. In conclusion, four out of every five PuP patients in this center had GPP. Corticosteroid withdrawal, upper respiratory tract infection, and pregnancy are important precipitating factors. Coexistence with other psoriasis variants was identified in one out of every three patients. Acitretin remains the mainstay of systemic treatment.

Recent advances in palmoplantar pustulosis

Palmoplantar pustulosis (PPP) is a chronic inflammatory condition where crops of sterile pustules with erythematous keratotic lesions causing bleeding and pain appear on the palms and soles. Recently, the European Rare and Severe Expert Network considered PPP as a variant of pustular psoriasis with or without psoriasis vulgaris.

The prevalence of PPP varies from 0.050 to 0.12%. PPP occurs more frequently in women and the highest prevalence occurred between the ages of 50 and 69 years. Nail psoriasis seems to be frequent in PPP, ranging from 30 to 76%, and psoriatic arthritis in 8.6 to 26% of PPP patients.

Synovitis, acne, pustulosis, hyperostosis, osteitis (SAPHO) syndrome and pustulotic arthro-osteitis are considered PPP-associated disorders. PPP has been reported with other co-morbidities such as psychiatric disorders, thyroid-associated disease, altered calcium homeostasis, gluten sensitivity diabetes, obesity, and dyslipidemia, but larger studies are required to prove such associations. Environmental exacerbating factors might contribute to the onset or worsening of PPP such as cigarette smoking, stress, focal infections, metal allergies, and drug intake. Genetic predisposition plays an important role in PPP.

In PPP, both the innate and the adaptive immune systems are activated. The acrosyringeal expression of IL-17 has been demonstrated, indicating that the eccrine sweat gland is an active component of the skin barrier and an immune-competent structure. Increased levels of several inflammatory molecules, including IL-8, IL-1α, IL-1β, IL-17A, IL-17C, IL-17D, IL-17F, IL-22, IL-23A, and IL-23 receptor, have been detected in PPP biopsies. Increased serum levels of TNF-α, IL-17, IL-22, and IFN-γ have been detected in patients with PPP in comparison to healthy subjects, suggesting a similar inflammatory pattern to psoriasis vulgaris. Oral and tonsillar infections serve as trigger factors for PPP.

Long-term therapy is required for many patients, but high-quality data are limited, contributing to uncertainty about the ideal approach to treatment.

Generalized pustular psoriasis: current management status and unmet medical needs in Japan

INTRODUCTION

Generalized pustular psoriasis (GPP) is a rare, inflammatory skin disease characterized by recurrent flares of pustulation accompanied by systemic symptoms that can be life-threatening. The clinical and humanistic burden of GPP in Japan is high, and it is a designated intractable disease. We reviewed clinical evidence and guidelines for GPP treatment in Japan to identify unmet needs and assess data supporting the development and use of new targeted therapies.

AREAS COVERED

Using specific search terms in PubMed and Embase, with additional back-referencing, we retrieved literature related to GPP in Japan focusing on clinical and pathogenic characteristics, diagnosis, and treatment.

EXPERT OPINION

Although there are approved systemic therapies for GPP in Japan, all present uncertainties in terms of safety and efficacy. Clinical evidence supporting their use comes mostly from studies in patients with mild or moderate disease, and their effectiveness in treating acute phase GPP is unknown. The interleukin-36 pathway appears to be central to GPP pathogenesis. New therapies targeting this pathway show promise in patients presenting with acute phase GPP. The rarity and intermittent course of GPP make it challenging to recruit sufficient patients for trials and robustly investigate the efficacy and safety of these agents to treat GPP.

Patient characteristics and burden of disease in Japanese patients with generalized pustular psoriasis: Results from the Medical Data Vision claims database

Generalized pustular psoriasis (GPP) is a rare and severe systemic, neutrophilic skin disease. To date, accurate clinical profiling of patients with GPP remains poorly understood. In this study, we present the characteristics and estimate the burden of disease in patients with GPP compared with those with plaque psoriasis, in Japan. This retrospective study was conducted using the Medical Data Vision database between January 1, 2015, and December 31, 2019. Patients with at least one confirmed inpatient or outpatient diagnostic code for GPP (L40.1) or psoriasis vulgaris (L40.0) were included for analysis. The main outcome measures included comparisons of the prevalence of comorbidities, medication use, and healthcare resource utilization between patients with GPP, patients with plaque psoriasis, and a general population‐matched cohort. In total, 718 patients with GPP and 27,773 patients with plaque psoriasis were identified. Patients with GPP were more likely to be female than those with plaque psoriasis (51.6% vs. 38.7%). During the 12‐month follow‐up period, patients with GPP were more likely to experience comorbidities than those with plaque psoriasis, including psoriatic arthritis, other forms of psoriasis, osteoporosis, interstitial pneumonia, and peptic ulcer disease. Medication use also differed between those with GPP and those with plaque psoriasis: patients with GPP were more likely to be prescribed antibiotics and psychiatric medication. Patients with GPP were also more likely to require more healthcare resource utilization with longer hospitalizations than those with plaque psoriasis. Overall, in Japan, patients with GPP have a higher burden of illness than those with plaque psoriasis.

Histologic Patterns and Clues to Autoinflammatory Diseases in Children: What a Cutaneous Biopsy Can Tell Us

Autoinflammation is defined by aberrant, antigen-independent activation of the innate immune signaling pathways. This leads to increased, pro-inflammatory cytokine expression and subsequent inflammation. In contrast, autoimmune and allergic diseases are antigen-directed immune responses from activation of the adaptive immune system. The innate and adaptive immune signaling pathways are closely interconnected. The group of 'complex multigenic diseases' are a result of mutual dysregulation of both the autoinflammatory and autoimmune physiologic components. In contrast, monogenic autoinflammatory syndromes (MAIS) result from single mutations and are exclusively autoinflammatory in their pathogenesis. Studying the clinical and histopathological findings for the various MAIS explains the phenotypical correlates of their specific mutations. This review aims to group the histopathologic clues for autoinflammation into three recognizable patterns. The presence of these histologic patterns in a pediatric patient with recurrent fevers and systemic inflammation should raise suspicion of an autoinflammatory component in MAIS, or, more frequently, in a complex multigenic disease. The three major histopathological patterns seen in autoinflammation are as follows: (i) the 'neutrophilic' pattern, seen in urticarial neutrophilic dermatosis, pustular psoriasis, aseptic neutrophilic folliculitis, and Sweet's syndrome; (ii) the 'vasculitic' pattern seen in small vessel-vasculitis (including hypersensitivity/leukocytoclastic vasculitis, thrombosing microangiopathy and lymphocytic vasculitis), and intermediate-sized vessel vasculitis, mimicking polyarteritis nodosa; and (iii) the 'granulomatous' pattern. Beyond these three patterns, there are additional histopathologic clues, which are detailed below. It is important for a dermatopathologist to recognize the patterns of autoinflammation, so that a diagnosis of MAIS or complex multigenic diseases may be obtained. Finally, careful histopathologic analyses could contribute to a better understanding of the various clinical manifestations of autoinflammation.

Economic burden of generalized pustular psoriasis and palmoplantar pustulosis in the United States

OBJECTIVE

To estimate healthcare resource utilization (HCRU) and economic burden of generalized pustular psoriasis (GPP) and palmoplantar pustulosis (PPP) in a commercially insured population the United States (US).

METHODS

Adult patients with a GPP or PPP diagnosis were identified between April 1, 2016 and August 1, 2019 in the IQVIA PharMetrics Plus database. Patients required continuous enrollment in medical and pharmacy benefits 6 months before and ≥2 months after the index diagnosis. GPP and PPP cohorts were exactly matched 1:3 on demographics and index date to a plaque psoriasis and a control cohort of the general population. All-cause HCRU and cost measures (direct medical and pharmacy) were reported as per patient per month (PPPM). Generalized linear models estimated adjusted cost ratios between matched cohorts, controlling for comorbidities.

RESULTS

HCRU was high among GPP and PPP patients. Rates of inpatient visits were 4 times higher in GPP patients and 2 times higher in PPP patients compared to their matched cohorts. GPP patients experienced significantly higher total healthcare costs compared to matched cohorts (GPP vs plaque psoriasis: cost ratio 1.36, 95% confidence interval (1.22, 1.50); GPP vs control: 5.58 (3.73, 8.36)). PPP patients had significantly higher total healthcare costs compared to the general population (4.11 (3.31, 5.11)), while costs were comparable to plaque psoriasis patients (1.06 (0.97, 1.16)).

CONCLUSIONS

GPP and PPP patients have significant economic burden due to higher direct medical and pharmacy costs. Further investigation is needed to better understand the drivers of economic burden in patients with GPP and PPP, and how HCRU and costs are impacted by disease severity.

Acrodermatitis Continua of Hallopeau Evolving into Generalized Pustular Psoriasis Following COVID-19: A Case Report of a Successful Treatment with Infliximab in Combination with Acitretin

The global pandemic of coronavirus disease 2019 (COVID-19) caused by the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is emerging. Various cutaneous manifestations have been observed in patients with SARS-CoV-2 infection, yet exacerbations of psoriasis have been reported sporadically. Acrodermatitis continua of Hallopeau (ACH) is an uncommon, sterile pustular dermatosis involving one or more digits. In some rare cases, ACH may evolve into generalized pustular psoriasis (GPP), which is a severe, and potentially life-threatening, form of psoriasis that manifests itself with widespread eruptions of pustules. We describe the first case of a patient in whom ACH abruptly progressed into GPP during COVID-19. A combination of infliximab and acitretin was used allowing swift clinical improvement.

Exploring the Role of IL-36 Cytokines as a New Target in Psoriatic Disease

Unmet needs in the treatment of psoriasis call for novel therapeutic strategies. Pustular psoriasis and psoriatic arthritis often represent a therapeutic challenge. Focus on IL-36 cytokines offers an interesting approach, as the IL-36 axis has been appointed a critical driver of the autoinflammatory responses involved in pustular psoriasis. Two IL-36R blocking antibodies, imsidolimab and spesolimab, are currently undergoing phase II and III clinical trials, with promising results.