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Acute generalized exanthematous pustulosis (AGEP) is a severe cutaneous adverse reaction (SCAR) characterized by sterile non-follicular pustules on an erythematous base that form rapidly after drug exposure. AGEP is mediated by numerous cytokines produced by drug specific T-cells that mediate neutrophilic intracorneal, subcorneal, and/or intraepidermal pustule development. Though genetic susceptibility is not fully understood, individuals with mutations in IL-36RN may be at increased risk of AGEP development. AGEP commonly presents with leukocytosis and fever in the acute pustular phase and follows a self-limited desquamative recovery phase upon removal of offending drug. Severe cases of AGEP may have multisystem organ involvement. Atypical presentations of AGEP include localized eruptions and cases with overlapping clinical and histopathological features associated with Stevens-Johnson syndrome/toxic epidermal necrolysis, drug reaction with eosinophilia and systemic symptoms, and generalized pustular psoriasis. Most cases of AGEP clear rapidly with systemic corticosteroids, but severe or recalcitrant cases may require other systemic therapies such as cyclosporine, and intravenous immunoglobulin.

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.

Background. This article discusses issues of diagnosis and management of pustular psoriasis in a child associated with recurrent dermatomycosis, immunopathogenetic mechanisms of pustular psoriasis, its course and prognosis. Clinical Case Description. The clinical case of infiltrative-suppurative form of scalp microsporia in 11 years old child with long-term psoriasis vulgaris and its transformation to generalized pustular psoriasis (von Zumbusch) is described. The need of immunosuppressive therapy prescription for severe psoriasis was challenged with fungal skin infection as immune suppression would lead to its recurrent course. Conclusion. Combination treatment (systemic glucocorticosteroids, methotrexate, antibiotics, and griseofulvin) resulted in clinical and laboratory recovery for microsporia in a child with generalized pustular psoriasis.

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.

Pustular psoriasis is an unusual form of psoriasis that frequently presents clinical challenges for dermatologists. The condition presents with pustules on an erythematous background and has two distinct subtypes: localized disease on the palms and soles, called palmoplantar pustulosis (PPP), and generalized pustular psoriasis (GPP). The involvement of the fingers, toes, and nails is defined as a separate localized variant, acrodermatitis continua of Hallopeau, and is now thought to be a subset of PPP. The rarity of pustular psoriasis frequently makes the correct diagnosis problematic. In addition, treatment is limited by a relative lack of evidence-based therapeutic options. Current management is often based on existing therapies for standard plaque psoriasis. However, there remains a need for treatments with high, sustained efficacy and a rapid onset of action in pustular psoriasis. Recent advances in understanding of the pathogenesis of pustular psoriasis have provided insights into potential therapies. Treatment of pustular psoriasis is generally determined by the extent and severity of disease, and recent years have seen an increasing use of newer agents, including biologic therapies. Current classes of biologic therapies with US Food and Drug Administration and European Medicines Agency approval for treatment of moderate-to-severe plaque psoriasis in the USA (and elsewhere) include tumor necrosis factor alpha inhibitors (adalimumab, certolizumab pegol, etanercept, infliximab), interleukin (IL)-17 inhibitors (brodalumab, ixekizumab, secukinumab), an IL-12/23 inhibitor (ustekinumab), and IL-23 inhibitors (guselkumab, risankizumab, tildrakizumab). Recently, specific inhibitors of the IL-36 pathway have been evaluated in GPP and PPP, including spesolimab, an IL-36 receptor inhibitor which has shown promising results in GPP. The emerging drugs for pustular psoriasis offer the possibility of rapid and effective treatment with lower toxicities than existing therapies. Further research into agents acting on the IL-36 pathway and other targeted therapies has the potential to transform the future treatment of patients with pustular psoriasis. This article reviews the clinical features of PPP and GPP, and current understanding of the genetics and immunopathology of these conditions; it also provides an update on emerging treatments. Supplementary Information The online version contains supplementary material available at 10.1007/s13555-021-00612-x., Plain Language Summary Pustular psoriasis is a skin condition where people develop small pus-filled blisters on their skin. Pustular psoriasis may affect certain areas of the body, such as the palms and/or the soles. This is called palmoplantar pustulosis (PPP for short). Another type of pustular psoriasis can affect most of the body called generalized pustular psoriasis (GPP for short). Not many people have PPP or GPP. Around 5–12 in every 10,000 people worldwide develop PPP. GPP is even rarer, affecting only 2–7 out of every 1 million people. In addition to being relatively uncommon, these conditions are challenging to treat. This article aims to help doctors who treat skin conditions (dermatologists) to identify and treat people with pustular psoriasis. Currently there is no standard treatment for GPP and PPP in the USA or Europe, but several medicines are approved for treatment of GPP in Japan. Doctors often use treatments that have been shown to work in plaque psoriasis, which is the most common type of psoriasis, to treat people with GPP and PPP. Traditional treatments for PPP and GPP are often not effective. Researchers are working on developing new effective treatments for pustular psoriasis that may work more rapidly and have fewer side effects. These are expected to be available in the next few years. Supplementary Information The online version contains supplementary material available at 10.1007/s13555-021-00612-x.

Introduction The various cutaneous manifestations have lately appeared in the setting of COVID‐19. Psoriasis flare‐ups have been reported during a COVID‐19 infection. Case presentation We present a case of a 32‐year‐old woman with COVID‐19 who presented with generalized pustular psoriasis. She received oral prednisolone, hydroxyzine, and topical clobetasol. The patient received follow‐up two weeks later and found that her lesions were favorably desquamating. Methods The PubMed, SCOPUS, and ISI Web of Science databases were thoroughly searched for English studies reporting psoriasis flare‐ups following SARS‐CoV‐2 infection. Ten case reports/series were included after screening. Conclusions Our case report brings awareness to clinicians for the possible cutaneous manifestation of COVID‐19, which should be considered part of the differential diagnoses.

The purpose of this narrative review article is to describe the current literature on the psoriasis inpatient population, discuss considerations for admission, and provide updated recommendations for inpatient psoriasis workup, management, and post-discharge follow-up. Studies report variable rates of psoriasis hospitalizations in the last decade even with the advent of highly efficacious outpatient therapies. Inequities in access to these therapies have resulted in disparities in the psoriasis inpatient population. Patients with severe variants of psoriasis, including generalized pustular and erythrodermic psoriasis, often have severe systemic complications and require immediate stabilization and supportive care. Traditional, rapid acting systemic therapies, including cyclosporine and infliximab, are efficacious, though the interleukin-17 inhibitors, secukinumab, ixekizumab, and brodalumab, may represent reasonable options. The interleukin-36 inhibitor, spesolimab, is a new and promising therapy under investigation for generalized pustular psoriasis. Psoriasis patients presenting with severe variants of disease, including pustular and erythrodermic psoriasis, in combination with systemic findings such as infection or compromised hemodynamic status, require hospitalization. Supportive measures to address systemic signs and complications are needed. Topical treatments with rapid acting systemic therapies should be employed to improve skin symptoms. Racial, ethnic, and insurance disparities exist in the hospitalized psoriasis patient population, highlighting the need for providers to obtain thorough sociodemographic histories and establish strong therapeutic alliances with these patients, identifying stable treatment options to prevent future exacerbations and hospitalizations.

Paradoxical reaction (PR) occurs when a drug elicits a reaction contrary to what was expected. To clarify the clinical features and genetic background of individuals susceptible to PR, we analyzed the clinical course of patients in whom psoriatic eruptions worsened or newly developed during tumor necrosis factor (TNF) antagonist administration and the role of focal infections and genetic variations. Of 125 patients who received TNF antagonist therapy for psoriasis, acrodermatitis continua of Hallopeau (ACH), generalized pustular psoriasis (GPP), or palmoplantar pustular psoriasis (PPP), eight patients with PR were surveyed at our hospital Dermatology Department between 2010 and 2021. A survey was also done on six patients who received TNF antagonist therapy for Crohn's disease, rheumatoid arthritis, ankylosing spondylitis, and hidradenitis suppurativa and were referred to our department due to PR. Additionally, Sanger sequencing analysis was performed for all exons and flanking introns of IL36RN (interleukin 36 receptor antagonist), CARD14 (caspase recruitment domain-containing protein 14), and AP1S3 (adaptor-related protein complex 1 subunit sigma 3). The clinical assessment of the 14 patients demonstrated an average age at PR onset of 48.4 years, a male : female ratio of 5:9, and a mean administration period until onset of 9.2 months. The clinical types of PR were plaque psoriasis, PPP, GPP, pustulosis, acne, ACH, hair loss, and exacerbation of arthralgia. Histopathology revealed psoriasiform dermatitis in three patients. One patient continued TNF antagonist therapy. All of the patients with psoriasis and GPP had dental infections, suggesting that focal infection may be a risk factor of the development of PR following TNF antagonist therapy. Gene analysis demonstrated CARD14 gene variants associated with RA, CD, AS, or PPP in four patients. In addition, all of the patients with ACH and PPP experienced PR, suggesting that these diseases may predispose patients to PR to TNF antagonist therapy.

Deficiency of the interleukin-36 receptor antagonist (DITRA) is an autosomal recessive disease caused by mutations of the IL36RN gene. DITRA is characterized by acute generalized pustular psoriasis (GPP), fever, systemic inflammation, and leukocytosis. We report the case of a 5-year-old girl with severe scalp and nail involvement with a rapid response to secukinumab.

Background:Generalized pustular psoriasis (GPP) is a rare, severe neutrophilic skin disease with high unmet clinical need. The introduction of a GPP-specific International Classification of Diseases, 10thRevision (ICD-10), code has made it possible to generate a more accurate GPP patient profile.Objectives:To describe the characteristics and compare the patient profile and burden of disease of patients with GPP with patients with plaque psoriasis.Methods:A retrospective study was conducted using a US administrative claims database, the IBM® MarketScan® Research Database. The study took place between October 1, 2015, and September 30, 2018. Patients with at least 1 inpatient or 2 outpatient L40.1 (GPP) or L40.0 (psoriasis vulgaris) diagnostic codes were included for analysis. Outcome measures included descriptions of comorbidities, medication use, and healthcare resource utilization (HCRU) among GPP, plaque psoriasis, and general population (matched to those with GPP) cohorts.Results:Patients with GPP had more baseline comorbidities than those with plaque psoriasis and the matched cohort, including psoriatic arthritis (20.6% vs 6.4% and Conclusion:Patients with GPP generally experience more comorbidities, with higher HCRU, than patients with plaque psoriasis. Although the large dataset permitted identification of GPP patients with longitudinal follow-up, the lack of a validation algorithm for GPP is a limitation and a potential area for future research.

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.

Generalized Pustular Psoriasis (GPP) is a rare, severe, life-threatening form of psoriasis and accounts for up to 13.1% of all childhood psoriasis. Common first-line systemic treatment for pediatric patients with GPP include oral acitretin, cyclosporin and methotrexate which have varying efficacy and side effects but multiple interventions are often needed to induce remission and maintain long term control. Recently, the anti IL 17 A monoclonal antibody secukinumab have been shown to be effective in adult patients with GPP; however, there is lack of evidence of its usage in the pediatric population. We describe a case series of 4 pediatric patients with GPP who were treated with off-label use of secukinumab. All four patients had marked clearance and reduction in Generalized Pustular Psoriasis AreaSeverity Score (GPPASI) within first 48 h of first injection with subsequent almost complete to complete clearance of skin lesions by 1 month follow up. In conclusion, secukinumab was found to be successful in inducing remission, with rapid clearance and maintaining remission, with or without combination with other systemic agents for pediatric GPP.

Psoriasis is a chronic inflammatory dermatosis with significant physical and psychological impact leading to negative influence on the quality of life among patients with psoriasis. Other than the disease characteristics many external factors could operate in South Asian context. Lack of a reliable disease-specific instrument prevents objective estimation and monitoring of disability in patients with psoriasis and hence we aim to validate assess the psychometric properties of the Sinhala version of PDI. A cross-sectional study conducted at dermatology clinic at a tertiary care National Hospital in Sri Lanka. Patients with psoriasis and on therapy at least 4 weeks prior to enrollment, aged more than 18 years, were included while those with already diagnosed psoriatic arthritis and/or nail psoriasis alone without any skin involvement and generalized pustular psoriasis de novo were excluded. All patients were examined by dermatologist to obtain disease characteristics. The reliability was assessed by internal consistency using Cronbach’s α and item-total correlation. Convergent validity was measured with the known groups. Of 199 patients studied, the PDI Sinhala version showed Cronbach’s α of 0.86 (all 15 items) and ranged from 0.57 to 0.77 for subscales. PDI score and Dermatology Life Quality Index (DLQI) showed good correlation of coefficient 0.76 (p

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.

Introduction Generalized pustular psoriasis (GPP) is a rare, severe, and potentially life-threatening systemic and chronic autoinflammatory disease characterized by sterile, neutrophilic pustules. The standard of care for GPP varies by region, with limited information and experience of flares and their treatment. Our aim was to establish current unmet needs in GPP by better understanding the natural history of GPP, examining how dermatologists diagnose GPP and GPP flares, and establishing the range and adequacy of GPP treatment options currently prescribed by dermatologists. Methods Eligible dermatologists (N = 29) completed a 28-question structured survey, covering ten themes, ranging from GPP diagnostic criteria to GPP symptoms and treatment. Results All dermatologists stated that pustules were necessary to diagnose a GPP flare. The most frequently reported triggering factors for GPP were steroid withdrawal (64%), infection (58%), and stress (50%). Most dermatologists indicated that available treatment options for GPP flares were adequate “most” (79%) or “all” (14%) of the time. Despite this reported adequacy, 38% of dermatologists reported that it was at least “somewhat common” for a flare to require hospitalization. Furthermore, 72% of dermatologists indicated that treatments were too slow to control flares, and 66% indicated that treatments did not adequately prevent new flares at least “sometimes”. Conclusion This survey suggests that there are key features of GPP flares, and could initiate discussion around forming consensus guidelines for diagnosis and management. While the results suggest that moderately effective therapies may exist, the need for GPP-specific treatments remains. Supplementary Information The online version contains supplementary material available at 10.1007/s13555-021-00493-0.

We present an interesting and novel case of a de novo generalized pustular psoriasis following administration of first dose of Oxford-AstraZeneca COVID-19 vaccine in a patient with no pre-existing psoriasis or any previous dermatological issue.

Generalized pustular psoriasis (GPP) is a rare variant of psoriasis with severe clinical symptoms. However, the quality of life (QoL) of the patients is largely unknown. We conducted a nationwide cross‐sectional survey of Japanese GPP patients using the 36‐Item Short‐Form Health Survey version 2 (SF‐36v2) to elucidate patients’ QoL and how their QoL had changed over the last decade. We analyzed QoL data of 83 patients obtained from 2016 to 2019 (present group) and compared it with that of 105 patients collected in a previous survey conducted between 2003 and 2007 (past group). Although the QoL of the present patients was still largely impaired in comparison with the standard Japanese population, substantial improvement was found in some SF‐36v2 subscales including “general health”, “vitality”, “social functioning” and “mental health” as compared with that of the past group. Advances in treatment may contribute to this QoL improvement.

Impetigo herpetiformis (IH) is a rare pustular dermatosis. It can be life-threatening for both the mother and fetus and often causes therapeutic problems. However, there is no specific guideline for the treatment of IH and the evidence regarding the efficacy of treatments for IH has not been established. Herein, we report two cases of IH, which were successfully treated with anti-tumor necrosis factor (TNF)-α drugs. The serum levels of the drugs in the infants and mothers were examined using enzyme-linked immunosorbent assay (ELISA). Case 1 was a 35-year-old, gravida 2, para 1, female patient in week 20 of pregnancy; she was treated with adalimumab (ADA) until delivery. Case 2 was a 26-year-old, gravida 1, para 0, female patient in week 30 of pregnancy; she was treated with certolizumab pegol (CZP) until delivery. In both cases, the skin lesions started regressing considerably after administration of the biologic agents. We examined the serum levels of the biologic agents in the mothers and infants using ELISA. In case 1, the ADA serum level in the infant was as high as that in the mother at birth; it then decreased below the lower limit of quantification at week 12 post-delivery. In case 2, the CZP serum level in the infant was below the lower limit of quantification at birth. In this report, we revealed that biologic agents could be an effective treatment for severe IH and that CZP treatment can be considered safe for the mothers and fetuses.

Acitretin, indicated for generalized pustular psoriasis, was effective in concomitant classic Kaposi sarcoma.

Introduction Ixekizumab has demonstrated rapid onset of action, high levels of skin clearance, and improvements in quality of life in patients with moderate-to-severe psoriasis, including plaque, erythrodermic, or generalized pustular psoriasis. Methods This was a post hoc analysis of UNCOVER-J, a phase 3, multicenter, single-arm, open-label study of ixekizumab for treatment of Japanese patients with psoriasis. The objective was to assess the proportion of patients who achieved Dermatology Life Quality Index (DLQI) (0,1) and Itch Numeric Rating Scale (NRS) (0) at weeks 4 and 12 according to Psoriasis Area and Severity Index (PASI) percentage improvement levels. All intent-to-treat patients with plaque, erythrodermic, or generalized pustular psoriasis were analyzed. Results A total of 91 patients were treated with ixekizumab and included in the analysis. Rapid improvements in PASI at weeks 4 and 12 were associated with improvements in DLQI (0,1) response at week 4 and at week 12. Complete skin clearance (PASI 100) achieved either at week 4 or week 12 was associated with a higher Itch NRS (0) response at week 12. Conclusions Patients with rapid improvement in clinical symptoms of psoriasis had better patient outcomes than those with slower responses. These findings highlight the clinical importance of achieving a fast response in patients with psoriasis, which may lead to better treatment outcomes. Trial Registration ClinicalTrials.gov identifier, NCT01624233. Graphic Abstract Electronic supplementary material The online version of this article (10.1007/s13555-020-00441-4) contains supplementary material, which is available to authorized users.

BACKGROUND: Impressive progress in new therapeutic options has been made for psoriasis. Treatments include topical steroids, phototherapy, conventional, synthetic disease-modifying drugs and an expanding list of biologics. OBJECTIVE: The primary objective of this work was to collect evidence for the creation of practice guidelines for systemic treatment of psoriasis (BETA-PSO: Belgian Evidence-based Treatment Advice in Psoriasis). METHODS: Evidence-based recommendations were formulated using a quasi-Delphi methodology after a systematic search of the literature and a consensus procedure involving 8 psoriasis experts. RESULTS: In this part, the use of systemic treatment in different age groups, during pregnancy, in metabolic syndrome, in patients with mental health problems, in different psoriasis subtypes and in previously systemically treated patients treatment is discussed. CONCLUSION: Guidance on therapeutic choice in specific clinical situations in psoriasis is provided in order to facilitate the decision-making in clinical practice. ispartof: JOURNAL OF THE EUROPEAN ACADEMY OF DERMATOLOGY AND VENEREOLOGY vol:34 issue:8 pages:1654-1665 ispartof: location:England status: published

We retrospectively analyzed 66 patients with palmoplantar pustulosis (PPP) from January 1994 to September 2019 in our department. Interleukin-36 receptor antagonist gene (IL36RN) intron 3 c.115+6T>C mutation was present in two out of 27 patients (7.4%). Both cases developed generalized pustular psoriasis and/or acrodermatitis continua of Hallopeau later. Topical medications and phototherapy were used in 93.9% and 28.8% of patients, respectively, while 60.6% received systemic agents. The majority of patients (60.6%) responded to treatment, but episodes of flare-up existed. The demographic data of our patients with PPP showed female predominance (59.1%), middle-age onset (44.2 years old) and current smokers (62.1%). Generalized pustular psoriasis initially presenting as palmoplantar lesions may be misdiagnosed as PPP, and the presence of IL36RN mutation may serve to predict or confirm the diagnosis of future generalized pustular psoriasis or acrodermatitis continua of Hallopeau. To our knowledge, this is the largest demographic study of PPP in Taiwan.

Generalized pustular psoriasis (GPP) is a severe form of psoriasis, which is rare in pediatric and adult patients. It is characterized by sterile pustular lesions that appear on erythematous skin, associated with systemic features. A recent identification of mutations in the IL36RN gene in some GPP patients has led to a diagnosis of new autoinflammatory disease, interleukin-36-receptor antagonist deficiency (DITRA). DITRA represents an emerging group of autoinflammatory diseases with hyperkeratotic skin involvement, called autoinflammatory keratinization diseases (AIKD). DITRA diagnosis and management are challenging as neither DITRA-specific clinical assessment tools nor treatment trials exist. Autoinflammatory Diseases Activity Index (AIDAI) is a validated tool originally developed to evaluate disease activity and treatment response in other inherited autoinflammatory diseases with systemic and skin involvement. We report the first use of AIDAI in a pediatric DITRA patient with the following goals: (a) to describe the contribution of AIDAI to our patient's management; (b) to identify potential limitations of AIDAI in DITRA; (c) to review literature for current psoriasis assessment tools; and (d) to propose a preliminary DITRA/AIKD disease activity index (DITRA/AIDAI) to be validated in future studies.

Autoinflammatory syndromes (AIS) are disorders of innate immunity which present with recurrent episodes of fever and skin lesions, such as urticaria, pustules, maculopapular rash, oral ulcers, generalized pustular psoriasis, or pyoderma gangrenosum-like lesions. The different entities that come under AIS are familial Mediterranean fever, tumor necrosis factor receptor-associated periodic syndrome, hyperimmunoglobulinemia D with periodic fever syndrome, and cryopyrin-associated periodic syndromes. Many new entities are also described. As many of them present with skin lesions, dermatologists should be aware of myriad of clinical features associated with these disorders. Childhood onset, positive family history, and elevated laboratory markers of systemic inflammation during acute episodes are the clues to diagnosis. Infections, connective tissue diseases, and malignancies should be excluded before diagnosing AIS.

Introduction: Generalized pustular psoriasis (GPP) is characterized by widespread erythema and edema, superficial sterile coalescing pustules, and lakes of pus. Although the impact of GPP is thought to be substantial, emerging literature on its clinical, humanistic, and economic burden has not previously been described in a structured way.Areas covered: A structured search focused on the identification of studies in GPP using specific search terms in PubMed and EMBASE® from 2005 onwards, with additional back-referencing and pragmatic searches. Outcomes of interest included clinical, humanistic, and economic burden.Expert opinion: Despite its significant clinical, humanistic, and economic burden, GPP is poorly classified and inadequately studied. A recent European (ERASPEN) consensus classifies GPP into relapsing and persistent disease and classifies patients on the presence or absence of psoriasis vulgaris. Classification of GPP lesions involving >30% body surface area or use of hospitalization as a surrogate may be a way to identify significant flares. Given the frequency of flares, the impaired quality of life during the post-flare period, and safety/tolerability issues, it is clear that current treatment options are not sufficient. Long-term studies utilizing the European consensus statement with subclassifiers are required to supplement our current understanding of the burden of GPP.

Background Palmoplantar pustulosis is considered to be a localized pustular psoriasis confined to the palms and soles. Mutation of the IL36RN gene, encoding interleukin-36 receptor antagonist (IL-36Ra), is associated with generalized pustular psoriasis, but IL36RN mutations in Chinese palmoplantar pustulosis patients have not previously been investigated. Objective The aim of this study was to evaluate the mutation of IL36RN in Chinese patients with palmoplantar pustulosis. Methods Fifty-one Han Chinese patients with palmoplantar pustulosis were recruited. All exons and exon-intron boundary sequences of IL36RN were amplified in polymerase chain reactions, and Sanger sequencing of the amplicons was performed. Results Among the 51 palmoplantar pustulosis patients, four different single-base substitutions were identified in nine patients. The mutations were c.140A>G/p.Asn47Ser in five patients, c.258G>A/p.Met86IIe in two patients, and c.115+6T>C and c.169G>A/p.Val57IIe in one patient each. All mutations were heterozygous. Comparison with the human genome database and reported literature suggested that these variants may not be pathogenic mutations causing palmoplantar pustulosis. Furthermore, there was no difference in disease severity, onset age, or disease duration between patients with these heterozygous IL36RN variants and those without (p > 0.1). Study limitation Lack of the further evaluation of IL36Ra protein in palmoplantar pustulosis lesions. Conclusions The four variants of IL36RN identified did not appear to be associated with the specific phenotypes of palmoplantar pustulosis.

Summary Background Neutrophilic dermatoses (ND) are a heterogeneous group of diseases, but can often have a relatively similar histological appearance. Aim To identify a combination of biomarkers allowing a better differentiation of ND types. Methods Biopsies were obtained from normal human skin (NS; n = 4), chronic plaque-type psoriasis (PsO; n = 7), paradoxical psoriasis (PP; n = 8), generalized pustular psoriasis (GPP; n = 9), subcorneal pustular dermatosis of Sneddon–Wilkinson (SPD; n = 3), acute generalized exanthematous pustulosis (AGEP; n = 3), hidradenitis suppurativa (HS; n = 7), Sweet syndrome (SS; n = 8) and pyoderma gangrenosum (PG; n = 8). Samples were analysed by immunofluorescence using three biomarkers, interleukin (IL)-17E, inducible nitric oxide synthase (iNOS) and arginase1, each one in combination with two cell markers, myeloperoxidase (MPO) and CD68, which allow the identification of neutrophils and macrophages, respectively. Results We found that SS is characterized by high expression of IL-17E and iNOS in the epidermis, while PG exhibits low expression. The density of the neutrophil infiltrate helps to differentiate PP (high-density infiltrate) from PsO (low-density infiltrate). High expression of arginase1 in the granular layer of the epidermis is a hallmark of SPD. Finally, mature neutrophils and proinflammatory macrophages are readily detectable in PP, SPD and PG, whereas immature neutrophils and anti-inflammatory macrophages are more frequent in GPP, AGEP, HS and SS. Conclusions The analysis of ND by immunofluorescence using IL-17E, iNOS and arginase1 in combination with MPO and CD68 allows for characterization of differential expression patterns in the epidermis as well as the determination of the polarization status of the dermal neutrophils and macrophages. The appropriate markers may help in the differentiation of ND in clinical practice.

BACKGROUND Psoriasis is a chronic, immune-mediated and hyperproliferative skin disease with both genetic and environmental components. Copy number variations (CNV) of IL22 and LCE3C-LCE3B deletion have been confirmed to be predisposed to psoriasis vulgaris (PsV) in several ethnic groups. However, it remains to be clarified whether CNVs of IL22 and LCE3C are associated with different subtypes of psoriasis (psoriatic arthritis, PsA; erythrodermic psoriasis, EP; and generalized pustular psoriasis, GPP). MATERIAL AND METHODS We enrolled 897 Han Chinese individuals, including 478 patients and 419 healthy controls, and detected CNVs of IL22 and LCE3C using the comparative CT method by real-time PCR, and Pearson's χ² test was used to evaluated the copy number difference among subtypes. RESULTS CNVs of IL22 were significantly higher in PsV than in healthy controls (P

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.

Acute generalized exanthematous pustulosis is a rare drug-induced eruption that is characterized by sterile non-follicular pustules arising on an often edematous diffuse erythematous background. Generalized pustular psoriasis is an acute and severe clinical form of psoriasis presenting as pustular eruption with erythematous base. Differentiating both diseases is often challenging because of their clinical and histopathological similarities. A 62-year-old woman presented with pustular eruption and fever three days after taking propyphenazone. Laboratory findings revealed leukocytosis and neutrophilia. Histopathological findings revealed a subcorneal spongiform pustule filled with neutrophils and perivascular inflammatory cell infiltration with neutrophils in the dermis. She was initially treated with systemic steroids, however, the lesions showed insignificant improvement. Treatment was then shifted to methotrexate which resulted in a dramatic clinical improvement.

We read with interest the article entitled "A case of de novo generalised pustular psoriasis following Oxford-AstraZeneca COVID-19 Vaccine" by Elamin et al.1 The authors describe a 66-year-old woman who developed new-onset generalised pustular psoriasis (GPP) three weeks after receiving first dose of Oxford-AstraZeneca COVID-19 Vaccine.1 The authors then contemplate on possible underlying immunopathologic mechanism.

Generalized pustular psoriasis is a rare variant of pustular psoriasis. During the pandemic of COVID-19, every patient referred to medical centers with fever or other flu-like symptoms would be first evaluated for COVID-19. Here, we report a case of pustular psoriasis who were under biologic immunosuppressive treatment (Infliximab) and was admitted to take her every eight weeks injection of infliximab. During evaluations before the injection, persistent fever and high CRP was detected. Due to these findings, she was suspected of having COVID-19, and this suspicion delayed routine medical care and infliximab infusion for her main disease, pustular psoriasis. After two negative results of the COVID-19 PCR test, Infliximab infusion was done, and surprisingly the fever disappeared, and CRP level decreased. © 2021 Tehran University of Medical Sciences. All rights reserved.

Background Psoriasis is a chronic immune‐mediated skin disorder. Systemic inflammation plays an important role in the pathogenesis of psoriasis. Methods A total of 477 patients with psoriasis vulgaris (PsV, n = 347), generalized pustular psoriasis (GPP, n = 37), erythrodermic psoriasis (PsE, n = 45), arthritic psoriasis (PsA, n = 25) and mixed psoriasis (n = 23), and 954 healthy control subjects were included in the study. Demographic, clinical, and laboratory information were collected and compared between subgroups. Results Compared with the healthy control group, patients with psoriasis had higher total white blood cell (WBC), neutrophil, platelet counts, neutrophil to lymphocyte ratio (NLR), and platelet to lymphocyte ratio (PLR), but lower hemoglobin (Hb) levels, lymphocyte and red blood cell (RBC) counts. NLR values in the PsV group were significantly lower than those in the GPP, PsE, and PsA groups, with GPP group being the highest. PLR values in the PsV group were significantly lower than those in the GPP, PsE, and PsA groups. There was no significant correlation between the psoriasis area severity index (PASI) score and either the NLR or PLR in the PsV group. Conclusions Elevated NLR and PLR were associated with psoriasis and differed between subtypes, suggesting that they could be used as markers of systemic inflammation in psoriasis patients.

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.

Marta Kołt-Kamińska, Magdalena Żychowska, Adam Reich Department of Dermatology, Institute of Medical Sciences, Medical College of Rzeszów University, Rzeszów, PolandCorrespondence: Magdalena ŻychowskaDepartment of Dermatology, Institute of Medical Sciences, Medical College of Rzeszów University, Reszów, PolandTel +48 66-942-2237Fax +48 17 86 66 294Email magda.zychowska@gmail.comAbstract: Generalized pustular psoriasis (GPP) is a severe, life-threatening disease that represents a major therapeutic challenge. There is a lack of randomized controlled trials assessing the efficacy of various treatment options for GPP. TNFα inhibitors have proven to be effective and are increasingly used in this indication. In the current paper, we present two patients with GPP treated with infliximab (Ifx) and a literature review appraising currently available data on the use of Ifx in GPP. Case 1 was a 73-year-old woman with GPP who exhibited lack of treatment response or primary intolerance to standard therapeutic options (high-dose acitretin, methotrexate, cyclosporine A, and methylprednisolone). However, Ifx therapy combined with low-dose acitretin resulted in rapid and sustained resolution of skin lesions. Case 2 was a 60-year-old man with GPP and numerous comorbidities who was initially treated with Ifx in combination with methotrexate, with good treatment response for 9 months. Following an infection-induced flare of GPP at week 38, methotrexate was discontinued in favor of low-dose acitretin and Ifx continued. This regimen again resulted in rapid resolution of pustules. We present these cases to highlight the advantage of long-term Ifx therapy with low-dose acitretin in GPP.Keywords: infliximab, anti-TNFα, generalized pustular psoriasis, acitretin

La psoriasis pustulosa anular es una patología poco frecuente, variante de la psoriasis pustulosa generalizada, donde la respuesta a los tratamientos es más variable y cuya fisiopatología involucra la mutación de los genes IL-36RN y CARD14. En la actualidad, son pocos los casos clínicos reportados en la literatura científica. Reportamos una paciente de 50 años con las características clínicas de esta enfermedad y su abordaje terapéutico. Se presenta una revisión de la literatura.

Generalized pustular psoriasis (GPP) is rare in the pediatric population, accounting for only 0.5-0.6% of psoriasis cases in children. This presents a diagnostic and therapeutic challenge, and often requires a biopsy to differentiate GPP from similar entities such as acute generalized exanthematous pustulosis, though controversy exists regarding the histologic distinction between the two. We describe a case of GPP in a 15-year-old male presenting with widespread pustular and bullous lesions, fever, and vital instability. The patient was diagnosed with GPP and successfully treated with cyclosporine 3mg/kg/day. He remains in remission on 25 mg acitretin daily. We present this case to highlight available treatment options for GPP in the pediatric population, and to underscore key clinical and histologic findings to aid dermatologists in proper diagnosis and management of this rare childhood disease.

This is a Japanese retrospective single-center study carried out between 1 January 2010 and 21 November 2018 at the Department of Dermatology in Jichi Medical University Hospital. The drug survival rate for six biologic agents used for the treatment of psoriasis was investigated. We reviewed the clinical records of 315 treatment series of 205 patients with moderate to severe psoriasis treated with adalimumab (103 cases), infliximab (70 cases), ustekinumab (66 cases), secukinumab (38 cases), brodalumab (12 cases) and ixekizumab (26 cases). In our study, ustekinumab revealed a trend towards higher drug survival among the six biologic agents. Ustekinumab had a higher drug survival rate than infliximab and secukinumab with significant differences by log-rank test among all patients and among biologic-naive (bio-naive) patients. There was no significant difference in drug survival between bio-naive and biologic-experienced (non-naive) patients in the treatment courses with adalimumab, infliximab, ustekinumab, secukinumab and ixekizumab. The dose augmentation therapy in infliximab-treated patients was associated with longer drug survival. Of all patients, 25 cases with generalized pustular psoriasis (GPP) were included, who functioned as the negative predictor for drug persistence with a hazard ratio of 1.87 (95% confidence interval, 1.12-3.11; P = 0.016). Our results reveal that ustekinumab had a superior drug survival, which is supported by the previous studies. Further studies are needed to clarify the efficacy of biologic agents on patients with GPP.

The correlation between polymorphisms at the tumor necrosis factor (TNF) gene and generalized pustular psoriasis (GPP) has rarely been reported. The goal of this study is to investigate whether TNF polymorphisms (-238 A/G, -308 A/G, -857C/T) are associated with susceptibility to GPP in a Han population from Eastern China and to perform subgroup analysis to explore the influence of age onset. Polymorphisms were assessed by polymerase chain reaction amplification and resequencing in 91 GPP patients and 102 healthy controls. The frequencies of the TNF -238A allele and GA+AA genotypes were significantly higher in GPP patients than in those of healthy controls. The subgroup analysis revealed that these significant associations were still present between -238A variants and pediatric-onset GPP patients who developed GPP at less than 18 years old (PGPP), but not for patients with adult-onset GPP who developed GPP at 18 years old or more. There were no significant differences in genotype or allele frequencies of TNF -308 A/G and -857C/T polymorphisms between GPP and controls. In conclusion, individuals carrying TNF -238A may be more susceptible to PGPP.

Introduction: Generalized pustular psoriasis (GPP) is a rare, severe relapsing/remitting, multisystem disease that can be difficult to treat. Recent clinical, histological, and genetic evidence suggests that GPP is a distinct clinical entity from plaque psoriasis and requires a separate diagnosis. The interleukin-36 pathway appears to be central to GPP pathogenesis. As no therapeutic agents have been approved for GPP to date in the United States or Europe, the introduction of anti-IL-36 therapies may change disease management. Areas covered: Using PubMed and Google Scholar, we reviewed the literature for articles related to GPP, psoriasis, and the genetics, pathogenesis, and treatment thereof. Expert opinion: New therapeutic options and updated guidelines for GPP treatment are needed. Ideal agents would have rapid onset of action and rapid time to achieve disease clearance, have the ability to prevent acute flares and avert recurrence, and possess a favorable safety profile. Such therapies should be readily accessible via approval or listing on formularies. Scoring systems to establish GPP disease burden and objective outcome measures could also help with further evaluation of therapies and treatment access issues. IL-36 remains a promising target, as supported by early phase data suggesting efficacy and safety for a novel anti-IL-36 therapy.

Acrodermatitis continua of Hallopeau (ACH) is a rare, sterile pustular eruption of one or more digits. The condition presents with tender pustules and underlying erythema on the tip of a digit, more frequently arising on a finger than a toe. As far as classification, ACH is considered a localized form of pustular psoriasis. The eruption typically occurs after local trauma or infection, but such a history is not always present and various other etiologies have been described including infectious, neural, inflammatory, and genetic causes. The natural progression of ACH is chronic and progressive, often resulting in irreversible complications such as onychodystrophy that can result in anonychia, as well as osteitis that can result in osteolysis of the distal phalanges. Because of the rarity of ACH, there have been no randomized controlled studies to evaluate therapies, resulting in an absence of standardized treatment guidelines. In clinical practice, a wide variety of treatments have been attempted, with outcomes ranging from recalcitrance to complete resolution. In recent years, the introduction of biologics has provided a new class of therapy that has revolutionized the treatment of ACH. Specifically, rapid and sustained responses have been reported with the use of anti-tumor necrosis factor agents like infliximab, adalimumab, and etanercept; IL-17 inhibitors like secukinumab; IL-12/23 inhibitors like ustekinumab; and IL-1 inhibitors like anakinra. Nevertheless, there remains a considerable need for more research into treatment for the benefit of individual patients with ACH as well as for the clinical knowledge gained by such efforts. The purpose of this review is to provide a comprehensive overview of the key features of ACH as well as a discussion of clinical management strategies for this unique and debilitating condition.

Generalized pustular psoriasis (GPP) is a rare and potentially life-threatening variant of psoriasis that is characterized by recurrent, acute onset, widely distributed pustular eruptions on inflamed, erythematous skin. It is important to recognize acute GPP as a subtype of psoriasis associated with high morbidity and mortality so therapy can be initiated without delay. Since GPP was first described in 1910 by Leopold von Zumbusch, it has been inconsistently defined, stratified, and diagnosed in the literature. Multiple definitions and diagnostic criteria have been proposed over the years. Recently, formal consensus guidelines on GPP have been published by international groups. This article reviews the current evidence and understanding in the diagnosis and screening of GPP.

Severe dermatitis, multiple allergies and metabolic wasting (SAM) syndrome is a recently recognized syndrome caused by mutations in the desmoglein 1 (DSG1) and desmoplakin (DSP) genes. Only two cases of SAM-DSP have been reported. We report on a 2-year-old girl presenting with pustular lakes within areas of erythema and large accumulations of intraepidermal neutrophils, which initially led to our misdiagnosis of generalized pustular psoriasis. No mutation was found in either the IL36RN or CARD14 genes by Sanger sequencing. The distinctive manifestations of erythroderma with severe itching, hypotrichosis, enamel defects, onychodystrophy, palmoplantar keratoderma and the crucial result of de novo missense mutation in exon 14 of the DSP gene (c.1828T>C, p.S610P) discovered by next-generation sequencing finally confirmed the diagnosis of SAM syndrome. The eruptions significantly improved after a 4-week treatment with oral acitretin and topical pimecrolimus. Oral gabapentin was prescribed simultaneously for 4 months, relieving her skin pruritus and suggesting that early treatment with pimecrolimus, acitretin and gabapentin for SAM-DSP syndrome is effective. It may even inhibit multiple allergies induced by skin barrier injury. In this work we also review the clinical features, differential diagnoses and pathological manifestations of SAM-DSP syndrome.

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.

OBJECTIVES Generalized pustular psoriasis (GPP) is a rare and severe, inflammatory skin disease. GPP is characterized by recurrent flares that consist of disseminated erythematous skin rash with sterile neutrophil-filled pustules that can result in an emergency department (ED) visit or hospital stay due to systemic complications. This study characterizes hospitalizations, ED visits, and inpatient treatment due to GPP in the United States (US). METHODS A descriptive, retrospective cross-sectional analysis was conducted in Cerner Health Facts, a US electronic medical record database. Hospitalizations and ED visits were identified between 1 October 2015 and 1 July 2017. Visits were included in the study if they were GPP-related, defined as a GPP diagnosis (ICD-10-CM code: L40.1) in the first or second position at admission or discharge, and if the discharge date was within the study period. Hospitalizations and ED visits were the units of analysis. Demographics, comorbidities, medication use, and outcomes were characterized with descriptive statistics. Outcomes included length of stay, intensive care unit (ICU) admission, and death. RESULTS A total of 71 GPP-related hospitalizations and 64 GPP-related ED visits were included in the study. Other specified inflammatory skin conditions (OSICS)/skin and subcutaneous tissue infections (54%/34%), fluid and electrolyte disorders (46%), hypertension (30%), septicemia (24%), and acute renal failure (18%) were the most frequently coded conditions accompanying a GPP-related hospitalization. OSICS/skin and subcutaneous tissue infections (47%/42%) were the most commonly coded conditions accompanying a GPP-related ED visit. Medication use during GPP-related hospitalizations included topicals (triamcinolone (42%); clobetasol (17%)), systemic corticosteroids (prednisone (20%); methylprednisolone (11%)), and non-biologic and biologic immunosuppressants (cyclosporine (6%); methotrexate (4%); etanercept (1%)). Analgesics (acetaminophen 67%; morphine 24%), and antibiotics (vancomycin 21%) were also common. The median length of stay for hospitalizations was 5 days. Three hospitalizations included an ICU admission and two hospitalizations resulted in death. CONCLUSIONS The presence of concurrent immune-mediated conditions, and frequent prescribing of analgesics, including opioids, illustrate the burden of GPP in patients requiring acute and inpatient care.

Pustular psoriasis (PsO) is an uncommon variant of PsO that may present in a generalized or localized fashion with or without musculoskeletal or systemic inflammatory involvement. Generalized pustular PsO (GPP) presents as a widespread acute or subacute pustular eruption that may be familial and is often associated with severe flares and systemic inflammation. The palmoplantar pustulosis variant is localized to palms and soles, whereas acrodermatitis continua of Hallopeau is localized to the nail apparatus. Patients with pustular PsO may have overlapping plaque PsO and may develop psoriatic arthritis (PsA). Pustulosis is also a feature of both synovitis, acne, pustulosis, hyperostosis, osteomyelitis (SAPHO) syndrome and chronic nonbacterial osteomyelitis. At the 2020 Group for Research and Assessment of Psoriasis and Psoriatic Arthritis (GRAPPA) annual meeting, members were given an overview of the cutaneous features of pustular PsO, SAPHO, and recent insights into the genetics of GPP, leading to new targeted drug therapies and the development of validated endpoints.