Association between psoriasis and celiac disease: A systematic review and meta-analysis

Role of Anti-Inflammatory Diet and Fecal Microbiota Transplant in Psoriatic Arthritis

PURPOSE

Psoriatic arthritis (PsA) is a chronic inflammatory condition with complex and heterogenous manifestations. Although a myriad of treatment options including biologic medications are available to alleviate symptoms and slow disease progression, there is currently no cure for this condition. There has been a recent emergence of understanding about the relationship between the gut microbiome and immune-mediated inflammatory diseases. This has generated interest in the potential role of dietary interventions, particularly anti-inflammatory diets, and fecal microbiota transplant (FMT) as novel therapeutic approaches. The purpose of this narrative review is to examine the role of an anti-inflammatory diet and FMT in turn and whether their combination may offer alternate approaches for the management of PsA.

METHODS

Our non-systematic narrative review was informed by a literature search using PubMed and Google Scholar using the terms anti-inflammatory diet, FMT, nutrition supplements, and PsA. Preclinical studies and non-English language articles were excluded when synthesizing the narrative review.

FINDINGS

Current randomized controlled trials (RCTs) and observational evidence suggest that a hypocaloric diet or Mediterranean diet can help achieve weight loss among PsA patients who are overweight or obese, which in turn reduces inflammation and improves disease activity. However, there is no strong data to support the beneficial effects of intermittent fasting, vitamin supplements, turmeric supplements, probiotics, or omega-3 fatty acid supplements in PsA. Current evidence on the use of FMT in PsA is limited as only one small RCT has been conducted which did not demonstrate efficacy for improving clinical symptoms.

IMPLICATIONS

Clinicians can consider recommending hypocaloric or Mediterranean diets as an adjunct to standard management of PsA, possibly under the guidance of a dietician. Further research is needed to explore the beneficial effects of the synergistic role of combining an anti-inflammatory diet with FMT in PsA.

Associations between Celiac Disease, Extra-Gastrointestinal Manifestations, and Gluten-Free Diet: A Narrative Overview

Millions of children and adults worldwide suffer from undiagnosed and untreated celiac disease (CeD). The clinical picture of CeD is highly heterogeneous and comprises manifestations that can affect almost the whole body. This narrative overview is aimed at characterizing diseases and complaints that are associated with unrecognized CeD and that frequently involve sites other than the gastrointestinal (G.I.) tract, i.e., dental, otorhinolaryngological, and ocular complications; skin and hair abnormalities; afflictions of the bones, joints, and muscles; cardiovascular affectations; kidney diseases; neuro-psychiatric disorders; and gynecological-obstetrical manifestations. The association between CeD and extra-GI manifestations is frequently overlooked, which leads to a delay in diagnosis. Most CeD-mediated disorders can be treated with a strict gluten-free diet (GFD), but some of them are irreversible unless CeD is diagnosed in time. Some manifestations can be classified as risk factors for CeD, and CeD screening tests for affected patients should be selectively considered. Apart from gastroenterologists, specialists in other medical disciplines can play an important role in identifying people with unrecognized CeD and may help prevent its progress and long-term complications. Further comprehensive investigations are necessary to clarify the pathogenesis of extra-GI manifestations and the effect of a GFD.

Celiac Disease-Related Conditions: Who to Test?

Celiac disease (CeD) is a chronic immune-mediated condition triggered by gluten consumption in genetically predisposed individuals. Approximately 1% of the general population is affected by the disorder. Disease presentation is heterogeneous and, despite growing awareness among physicians and the public, it continues to be underestimated. The most effective strategy for identifying undiagnosed CeD is proactive case finding through serologic testing in high-risk groups. We reviewed the most recent evidence on the association between CeD and more than 20 conditions. In light of this review, CeD screening is recommended in individuals with (1) autoimmune disease and accompanying symptoms suggestive of CeD; (2) diseases that may mimic CeD (eg, irritable bowel syndrome [IBS], inflammatory bowel disease [IBD], and microscopic colitis); and (3) among patients with conditions with a high CeD prevalence: first-degree relatives, idiopathic pancreatitis, unexplained liver enzyme abnormalities, autoimmune hepatitis, primary biliary cholangitis, hyposplenism or functional asplenia with severe bacterial infection, type 1 diabetes mellitus, Hashimoto's thyroiditis and Graves' disease, Sjögren's syndrome, dermatitis herpetiformis, recurrent aphthous syndrome and enamel defects, unexplained ataxia, peripheral neuropathy, delayed menarche or premature menopause, Down syndrome, Turner syndrome, Williams syndrome, chronic fatigue syndrome, IgA nephropathy, and IgA deficiency. CeD serology should be the initial step in the screening process. However, for patients with any of the aforementioned disorders who are undergoing upper endoscopy, biopsies should be performed to rule out CeD.

Popular Diets and Skin Effects: A Narrative Review

Numerous diets for losing weight, building strength, and managing a range of cardiovascular, neurologic, and skin diseases have become popular in recent years. The ketogenic diet and intermittent fasting in particular have shown promising results in clinical and sports medicine. The Mediterranean diet, in turn, is widely recognized for its numerous health benefits. Also popular are the paleo diet and vegan and gluten-free diets. Positive effects on inflammatory conditions, such as psoriasis, atopic dermatitis, hidradenitis suppurativa, and acne, have been observed in patients who practice intermittent fasting or follow ketogenic or Mediterranean diets. This last choice may also protect against certain skin cancers. We review the role of several popular diets in the management of skin disorders.

[Translated article] Popular Diets and Skin Effects: A Narrative Review

Numerous diets for losing weight, building strength, and managing a range of cardiovascular, neurologic, and skin diseases have become popular in recent years. The ketogenic diet and intermittent fasting in particular have shown promising results in clinical and sports medicine. The Mediterranean diet, in turn, is widely recognized for its numerous health benefits. Also popular are the paleo diet and vegan and gluten-free diets. Positive effects on inflammatory conditions, such as psoriasis, atopic dermatitis, hidradenitis suppurativa, and acne, have been observed in patients who practice intermittent fasting or follow ketogenic or Mediterranean diets. This last choice may also protect against certain skin cancers. We review the role of several popular diets in the management of skin disorders.

Psoriasis, bone and bowel: a comprehensive review and new insights

Psoriasis is a chronic immune-mediated disorder affecting about 2% of the population worldwide which is associated with significant morbidity. The disease usually presents as raised, well-demarcated erythematous plaques with adherent silvery scales. Psoriasis can appear at any age but it has two peaks occurring at 15–20 and 55–60 years of age. It affects males and females equally. Despite the multitude of investigations about psoriasis and even development of drugs with satisfactory results, its pathogenesis is not fully understood yet and its course is unpredictable. Various environmental triggers, e.g., obesity, stress and drugs may induce disease in genetically susceptible patients. Although psoriasis was considered primarily as a disease of the skin, more investigations have been revealed its systemic nature. Psoriatic arthritis (PsA) may complicate up to one-third of cases of psoriasis vulgaris (PV). Also, the association between psoriasis and a variety of other immune-mediated disorders such as inflammatory bowel disease (IBD) and celiac disease (CD) has been confirmed in various studies. Moreover, a growing body of evidences indicates that psoriasis shares some common histological and phenotypical properties with the spectrum of osteoimmunological diseases such as Paget’s disease of bone (PDB). Thus, exploring the common molecular and genetic mechanisms underlying psoriasis and related disorders is of paramount importance for better elucidating disease pathogenesis and designing more targeted treatments.

The role of nutrition, food allergies, and gut dysbiosis in immune-mediated inflammatory skin disease: a narrative review

PURPOSE OF REVIEW

This review focuses on the emerging roles of nutrition, food allergies, and gut dysbiosis, and their influence on pediatric skin conditions such as psoriasis, hidradenitis suppurativa, and alopecia areata. As the prevalence of these conditions increases, understanding the underlying mechanisms and potential therapeutic targets is crucial for clinical practice and research.

RECENT FINDINGS

The review covers 32 recent articles that highlight the significance of the gut microbiome, nutrition, and gut dysbiosis in the pathogenesis and progression of inflammatory and immune-related pediatric skin conditions. The data suggest that food allergies and gut dysbiosis play a crucial role in disease pathogenesis.

SUMMARY

This review emphasizes the need for larger-scale studies to determine the effectiveness of dietary changes in preventing or treating inflammatory and immune-related skin conditions. Clinicians must maintain a balanced approach when implementing dietary changes in children with skin diseases like atopic dermatitis to avoid potential nutritional deficiencies and growth impairments. Further research into the complex interplay between environmental and genetic factors is warranted to develop tailored therapeutic strategies for these skin conditions in children.

Skin gluten-related disorders: new and old cutaneous manifestations to be considered

The term gluten-related disorders (GRD) refer to a spectrum of different clinical manifestations triggered by the ingestion of gluten in genetically susceptible individuals, including coeliac disease (CD), wheat allergy and non-celiac gluten sensitivity (NCGS). GRD are characterized by a large variety of clinical presentations with both intestinal and extra-intestinal manifestations. The latter may affect almost every organ of the body, including the skin. Besides the well-known association between CD and dermatitis herpetiformis, considered as the cutaneous specific manifestation of CD, many other muco-cutaneous disorders have been associated to GRD. In this review, we analyzed the main features of dermatological diseases with a proven association with GRD and those that improve after a gluten-free diet, focusing on the newly described cutaneous manifestations associated with NCGS. Our main hypothesis is that a "cutaneous-gluten sensitivity," as specific cutaneous manifestation of NCGS, may exist and could represent a diagnostic marker of NCGS.

Screening of antigliadin and antitissue transglutaminase antibodies in patients with chronic plaque psoriasis: a case-control study

BACKGROUND

In this study, we aimed to investigate different types of celiac antibodies in psoriasis patients and to see if the presenceof the antibodies was associated with other variables.

METHODS

We included patients with plaque psoriasis who were followed up in our dermatology clinic between February 2019 and February 2021 and added a healthy control group for comparison. The antibodies studied were serum antitissue transglutaminase (tTG)-IgA, tTG-IgG, antigliadin antibody (AGA)-IgA, and AGA-IgG. The patients' records were used to note age, sex, the pattern of psoriasis involvement, psoriasis area and severity index (PASI), presence of hypertension, presence of type 2 diabetes mellitus, use of methotrexate, and use of biologic agents.

RESULTS

Sixty-five psoriasis patients (31 F, 34 M, mean age: 38.9 ± 15.2) and 65 controls (42 F, 23 M, mean age: 40.7 ± 13.2) wereincluded in the study. There was no significant difference in antibody levels between the groups: tTG-IgA (2.4 U/mL vs 3.2 U/mL, p = 0.11), tTG-IgG (2.2 U/mL vs 3.2 U/mL, p = 0.74), AGA-IgA (2.4 U/mL vs 3.5 U/mL, p = 0.068), and AGA-IgG (3.2 U/mL vs 4.2 U/mL, p = 0.15). One patient from the psoriasis group only had borderline positive antibody levels whereas the rest of the psoriasis and control group had negative levels. Hypertensive psoriasis patients had significantly higher AGA-IgA titers compared to normotensive psoriasis patients (4.2 U/mL vs 2.3 U/mL, p = 0.005).

DISCUSSION

There was no increase in the AGA-IgA/IgG and tTG-IgA/IgG levels in psoriasis patients compared to the healthy population. However, hypertensive psoriasis patients had higher AGA-IgA levels compared to normotensive ones.

The Role of Diet in Children with Psoriasis: Emerging Evidence and Current Issues

Psoriasis is an immune-mediated inflammatory systemic disease with skin tropism and chronic relapsing course; it is associated with an increased cardiovascular risk and with many metabolic comorbidities, emerging during childhood in 22–33% of cases. Diet influences the presentation and the clinical course of inflammatory diseases, including psoriasis; in particular, it was shown that a Mediterranean, gluten-free, or low-calorie diet may positively affect disease control in adult patients with psoriasis and adequate pharmacological therapy. These three dietary regimens may play a role also in children with psoriasis. It has been demonstrated that pediatric psoriasis is associated with psychological stress, celiac disease, and obesity, which may be positively influenced by these dietary regimens, respectively. Therefore, the expertise of multiple health figures (gastroenterologists, nutritionists, pediatricians, dermatologists) is required to plan a tailor-made dietary strategy, ensuring good growth, through an adequate intake of essential micro- and macronutrients and, at the same time, impacting the pro-inflammatory biochemical profile and on the associated cardiovascular risk of psoriasis disease.

Mendelian randomization study of the genetic interaction between psoriasis and celiac disease

Epidemiological studies have observed some relationship between psoriasis and celiac disease (CD), while the causal link between these 2 autoimmune diseases was unclear. In the current study, we aimed to explore the causal link between psoriasis and celiac disease with bidirectional 2-sample Mendelian Randomization (MR) study. Eligible instrument variables (IVs) with genome-wide significance (p < 5E-08) were extracted from the summary-level datasets from the published genome-wide association studies (GWAS), which were conducted in the European population. The inverse variance weighted (IVW) method was performed as the main analysis, sensitivity analyses and post-MR analyses were also performed. Our MR analyses found that genetically doubling the odds of CD would increase the risk for psoriasis (p = 1.58e-03, OR [95% CI] 1.232 [1.061-1.432]). And the results were supported by sensitivity analyses. While we found that genetically determined psoriasis was not associated with the risk for CD (IVW: p = 0.985, OR [95% CI] 1.000 [0.965-1.037]). Our study provided novel genetic evidence that patients with CD were at an increased risk of developing psoriasis, while psoriasis was not associated with the risk for CD. Clinicians should be aware of the associations and pay attention to skin manifestations in patients with CD.

Pathogenesis, multi-omics research, and clinical treatment of psoriasis

Psoriasis is a common inflammatory skin disease involving interactions between keratinocytes and immune cells that significantly affects the quality of life. It is characterized by hyperproliferation and abnormal differentiation of keratinocytes and excessive infiltration of immune cells in the dermis and epidermis. The immune mechanism underlying this disease has been elucidated in the past few years. Research shows that psoriasis is regulated by the complex interactions among immune cells, such as keratinocytes, dendritic cells, T lymphocytes, neutrophils, macrophages, natural killer cells, mast cells, and other immune cells. An increasing number of signaling pathways have been found to be involved in the pathogenesis of psoriasis, which has prompted the search for new treatment targets. In the past decades, studies on the pathogenesis of psoriasis have focused on the development of targeted and highly effective therapies. In this review, we have discussed the relationship between various types of immune cells and psoriasis and summarized the major signaling pathways involved in the pathogenesis of psoriasis, including the PI3K/AKT/mTOR, JAK-STAT, JNK, and WNT pathways. In addition, we have discussed the results of the latest omics research on psoriasis and the epigenetics of the disease, which provide insights regarding its pathogenesis and therapeutic prospects; we have also summarized its treatment strategies and observations of clinical trials. In this paper, the various aspects of psoriasis are described in detail, and the limitations of the current treatment methods are emphasized. It is necessary to improve and innovate treatment methods from the molecular level of pathogenesis, and further provide new ideas for the treatment and research of psoriasis.

Defining the optimum strategy for identifying adults and children with coeliac disease: systematic review and economic modelling

BACKGROUND

Coeliac disease is an autoimmune disorder triggered by ingesting gluten. It affects approximately 1% of the UK population, but only one in three people is thought to have a diagnosis. Untreated coeliac disease may lead to malnutrition, anaemia, osteoporosis and lymphoma.

OBJECTIVES

The objectives were to define at-risk groups and determine the cost-effectiveness of active case-finding strategies in primary care.

DESIGN

(1) Systematic review of the accuracy of potential diagnostic indicators for coeliac disease. (2) Routine data analysis to develop prediction models for identification of people who may benefit from testing for coeliac disease. (3) Systematic review of the accuracy of diagnostic tests for coeliac disease. (4) Systematic review of the accuracy of genetic tests for coeliac disease (literature search conducted in April 2021). (5) Online survey to identify diagnostic thresholds for testing, starting treatment and referral for biopsy. (6) Economic modelling to identify the cost-effectiveness of different active case-finding strategies, informed by the findings from previous objectives.

DATA SOURCES

For the first systematic review, the following databases were searched from 1997 to April 2021: MEDLINE® (National Library of Medicine, Bethesda, MD, USA), Embase® (Elsevier, Amsterdam, the Netherlands), Cochrane Library, Web of Science™ (Clarivate™, Philadelphia, PA, USA), the World Health Organization International Clinical Trials Registry Platform ( WHO ICTRP ) and the National Institutes of Health Clinical Trials database. For the second systematic review, the following databases were searched from January 1990 to August 2020: MEDLINE, Embase, Cochrane Library, Web of Science, Kleijnen Systematic Reviews ( KSR ) Evidence, WHO ICTRP and the National Institutes of Health Clinical Trials database. For prediction model development, Clinical Practice Research Datalink GOLD, Clinical Practice Research Datalink Aurum and a subcohort of the Avon Longitudinal Study of Parents and Children were used; for estimates for the economic models, Clinical Practice Research Datalink Aurum was used.

REVIEW METHODS

For review 1, cohort and case-control studies reporting on a diagnostic indicator in a population with and a population without coeliac disease were eligible. For review 2, diagnostic cohort studies including patients presenting with coeliac disease symptoms who were tested with serological tests for coeliac disease and underwent a duodenal biopsy as reference standard were eligible. In both reviews, risk of bias was assessed using the quality assessment of diagnostic accuracy studies 2 tool. Bivariate random-effects meta-analyses were fitted, in which binomial likelihoods for the numbers of true positives and true negatives were assumed.

RESULTS

People with dermatitis herpetiformis, a family history of coeliac disease, migraine, anaemia, type 1 diabetes, osteoporosis or chronic liver disease are 1.5-2 times more likely than the general population to have coeliac disease; individual gastrointestinal symptoms were not useful for identifying coeliac disease. For children, women and men, prediction models included 24, 24 and 21 indicators of coeliac disease, respectively. The models showed good discrimination between patients with and patients without coeliac disease, but performed less well when externally validated. Serological tests were found to have good diagnostic accuracy for coeliac disease. Immunoglobulin A tissue transglutaminase had the highest sensitivity and endomysial antibody the highest specificity. There was little improvement when tests were used in combination. Survey respondents (n = 472) wanted to be 66% certain of the diagnosis from a blood test before starting a gluten-free diet if symptomatic, and 90% certain if asymptomatic. Cost-effectiveness analyses found that, among adults, and using serological testing alone, immunoglobulin A tissue transglutaminase was most cost-effective at a 1% pre-test probability (equivalent to population screening). Strategies using immunoglobulin A endomysial antibody plus human leucocyte antigen or human leucocyte antigen plus immunoglobulin A tissue transglutaminase with any pre-test probability had similar cost-effectiveness results, which were also similar to the cost-effectiveness results of immunoglobulin A tissue transglutaminase at a 1% pre-test probability. The most practical alternative for implementation within the NHS is likely to be a combination of human leucocyte antigen and immunoglobulin A tissue transglutaminase testing among those with a pre-test probability above 1.5%. Among children, the most cost-effective strategy was a 10% pre-test probability with human leucocyte antigen plus immunoglobulin A tissue transglutaminase, but there was uncertainty around the most cost-effective pre-test probability. There was substantial uncertainty in economic model results, which means that there would be great value in conducting further research.

LIMITATIONS

The interpretation of meta-analyses was limited by the substantial heterogeneity between the included studies, and most included studies were judged to be at high risk of bias. The main limitations of the prediction models were that we were restricted to diagnostic indicators that were recorded by general practitioners and that, because coeliac disease is underdiagnosed, it is also under-reported in health-care data. The cost-effectiveness model is a simplification of coeliac disease and modelled an average cohort rather than individuals. Evidence was weak on the probability of routine coeliac disease diagnosis, the accuracy of serological and genetic tests and the utility of a gluten-free diet.

CONCLUSIONS

Population screening with immunoglobulin A tissue transglutaminase (1% pre-test probability) and of immunoglobulin A endomysial antibody followed by human leucocyte antigen testing or human leucocyte antigen testing followed by immunoglobulin A tissue transglutaminase with any pre-test probability appear to have similar cost-effectiveness results. As decisions to implement population screening cannot be made based on our economic analysis alone, and given the practical challenges of identifying patients with higher pre-test probabilities, we recommend that human leucocyte antigen combined with immunoglobulin A tissue transglutaminase testing should be considered for adults with at least a 1.5% pre-test probability of coeliac disease, equivalent to having at least one predictor. A more targeted strategy of 10% pre-test probability is recommended for children (e.g. children with anaemia).

FUTURE WORK

Future work should consider whether or not population-based screening for coeliac disease could meet the UK National Screening Committee criteria and whether or not it necessitates a long-term randomised controlled trial of screening strategies. Large prospective cohort studies in which all participants receive accurate tests for coeliac disease are needed.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42019115506 and CRD42020170766.

FUNDING

This project was funded by the National Institute for Health and Care Research ( NIHR ) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 26, No. 44. See the NIHR Journals Library website for further project information.

Psoriasis and medical ramifications: A comprehensive analysis based on observational meta-analyses

Purpose

Based on a large number of systematic reviews and meta-analyses exploring the relationship between psoriasis and various health outcomes, we conducted an comprehensive analysis to assess the strength and evidence for the association between psoriasis and medical end-point ramifications in patients.

Methods

We searched related meta-analyses, investigating the links between psoriasis and medical ramifications from three databases. All summary effect sizes, 95% CIs, heterogeneity, and small-study effects in the included meta-analyses were recalculated. We assessed the methodological quality of included articles with the AMSTAR 2 tool and graded the epidemiological evidence. Subgroup analysis based on the severity of psoriasis and study design were also performed.

Results

A total of 38 articles comprising 85 unique meta-analyses were included in this study. Although 69 outcomes were statistically significant, only 8 outcomes (nonvascular dementia, ulcerative colitis, pediatric dyslipidemia, gestational diabetes, gestational hypertension, fracture, multiple sclerosis, and schizophrenia) showed a high quality of epidemiological evidence.

Conclusion

We found that psoriasis increased the risk of 69 health outcomes, and 8 outcomes were graded as high-quality evidence. No evidence was found that psoriasis was beneficial for any medical end point. However, to verify our results, more large-sample, multi-center prospective cohort studies are needed.

Gut Microbiota in Psoriasis

Psoriasis is a chronic inflammatory skin disease with autoimmune pathogenic characteristics and is caused by chronic inflammation, which results in uncontrolled keratinocyte growth and defective differentiation. The link between the gut microbiota and immune system regulation opened a novel angle to understand the pathogenesis of many chronic multifactorial diseases, including psoriasis. Current evidence suggests that modulation of the gut microbiota, both through dietary approaches and through supplementation with probiotics and prebiotics, could represent a novel therapeutic approach. The present work aims to highlight the latest scientific evidence regarding the microbiome alterations of psoriatic patients, as well as state of the art insights in terms of microbiome-targeted therapies as promising preventive and therapeutic tools for psoriasis.

The Role of Lifestyle and Nutrition in Psoriasis: Current Status of Knowledge and Interventions

Extrinsic environmental factors, including patient lifestyle (alcohol intake, smoking, stress, sleep disturbances, and sedentary habit), diet and single nutrients intake may affect psoriasis clinical presentation, severity, and course. All English language articles dealing with psoriasis and lifestyle factors or diet gathered by an extensive PubMed search were carefully examined in order to explore their impact on the disease. Current authoritative knowledge confirms that low‐calories, Mediterranean, and protein restricted/vegetarian diets may be beneficial. Psoriatic patients are also recommended to engage regular physical activity, to avoid alcohol intake and to consume fish rich in omega‐3 polyunsaturated fatty acids, as well as fruit and vegetables. Prebiotics and probiotics may also provide potential benefit, whereas vitamin D supplementation and gluten‐free diet are useful in selected cases only. Changing of dietary and lifestyle habits alone does not replace conventional treatment, but must be considered as an adjuvant. Physicians may play a crucial role, by adequately acknowledging psoriatic patients on the advantages of proper lifestyle and diet habits as well as providing clues to reliable sources of dietary advice.

Epidemiology of Psoriasis and Comorbid Diseases: A Narrative Review

Psoriasis is a chronic autoimmune inflammatory disease that remains active for a long period, even for life in most patients. The impact of psoriasis on health is not only limited to the skin, but also influences multiple systems of the body, even mental health. With the increasing of literature on the association between psoriasis and extracutaneous systems, a better understanding of psoriasis as an autoimmune disease with systemic inflammation is created. Except for cardiometabolic diseases, gastrointestinal diseases, chronic kidney diseases, malignancy, and infections that have received much attention, the association between psoriasis and more systemic diseases, including the skin system, reproductive system, and oral and ocular systems has also been revealed, and mental health diseases draw more attention not just because of the negative mental and mood influence caused by skin lesions, but a common immune-inflammatory mechanism identified of the two systemic diseases. This review summarizes the epidemiological evidence supporting the association between psoriasis and important and/or newly reported systemic diseases in the past 5 years, and may help to comprehensively recognize the comorbidity burden related to psoriasis, further to improve the management of people with psoriasis.

Dietary Intervention and Supplements in the Management of Psoriasis: Current Perspectives

Nutrition is a complex topic encompassing diet and a variety of supplements including vitamins, fish oil, herbal products, and probiotics. Patients with psoriasis display high interest in understanding the potential impact of nutritional modifications on their psoriasis. In this review, we examine the evidence for nutritional interventions in psoriasis and summarize important concepts. We found that certain diets, such as low-calorie diets for obese patients, gluten-free diets for patients with comorbid celiac disease, and the Mediterranean diet, may have benefits for psoriasis patients. Supplements in general do not show strong evidence of benefit, though more studies are required given the heterogeneity of these trials. Finally, the gut microbiome has drawn considerable interest in recent years, with specific probiotics showing promising results for psoriasis patients and warranting further exploration.

Effect of diet and weight loss on the severity of psoriasis

Psoriasis is one of the most common chronic inflammatory skin diseases, constituting a significant health and socioeconomic problem. Despite numerous therapeutic options, the results of treatment often remain insufficient. This may be due to the lack of compliance with medical prescriptions and patients’ limited knowledge of their disease. Psoriatic patient's skin well-being is affected by many factors, including lifestyle. The course of the disease is affected by obesity, improper diet, and stimulants. Often these factors coexist. Excessive weight gain in psoriasis can be caused by a decrease in physical activity, caused by feelings of social stigma, coexistence of psoriatic arthritis, depression, and increased alcohol consumption. Several studies have confirmed that the average fat, protein, and calorie content in the diet of a patient with psoriasis are above the recommended norms. On the other hand, adhering to a low calorie, reducing diet results in a clinically significant improvement in the Psoriasis Area Severity Index (PASI) and patients’ quality of life (i.e., reduction of Dermatology Life Quality Index [DLQI]). Weight reduction caused by diet and exercise reduces the severity of skin lesions, even in people who have not achieved improvement after general treatment. Therefore, it is important to educate the patient about the nature of the disease at the very beginning of treatment. Patients with moderate to severe forms of the disease are predisposed to the development of cardiovascular diseases, obesity, diabetes, and anxiety. That is why plaque psoriasis requires a comprehensive treatment and a holistic approach to the patient.

The accuracy of diagnostic indicators for coeliac disease: A systematic review and meta-analysis

BACKGROUND

The prevalence of coeliac disease (CD) is around 1%, but diagnosis is challenged by varied presentation and non-specific symptoms and signs. This study aimed to identify diagnostic indicators that may help identify patients at a higher risk of CD in whom further testing is warranted.

METHODS

International guidance for systematic review methods were followed and the review was registered at PROSPERO (CRD42020170766). Six databases were searched until April 2021. Studies investigating diagnostic indicators, such as symptoms or risk conditions, in people with and without CD were eligible for inclusion. Risk of bias was assessed using the QUADAS-2 tool. Summary sensitivity, specificity, and positive predictive values were estimated for each diagnostic indicator by fitting bivariate random effects meta-analyses.

FINDINGS

191 studies reporting on 26 diagnostic indicators were included in the meta-analyses. We found large variation in diagnostic accuracy estimates between studies and most studies were at high risk of bias. We found strong evidence that people with dermatitis herpetiformis, migraine, family history of CD, HLA DQ2/8 risk genotype, anaemia, type 1 diabetes, osteoporosis, or chronic liver disease are more likely than the general population to have CD. Symptoms, psoriasis, epilepsy, inflammatory bowel disease, systemic lupus erythematosus, fractures, type 2 diabetes, and multiple sclerosis showed poor diagnostic ability. A sensitivity analysis revealed a 3-fold higher risk of CD in first-degree relatives of CD patients.

CONCLUSIONS

Targeted testing of individuals with dermatitis herpetiformis, migraine, family history of CD, HLA DQ2/8 risk genotype, anaemia, type 1 diabetes, osteoporosis, or chronic liver disease could improve case-finding for CD, therefore expediting appropriate treatment and reducing adverse consequences. Migraine and chronic liver disease are not yet included as a risk factor in all CD guidelines, but it may be appropriate for these to be added. Future research should establish the diagnostic value of combining indicators.

Skin Manifestations and Coeliac Disease in Paediatric Population

Celiac disease (CD) is an immune-mediated enteropathy caused by gluten ingestion, affecting approximately 1% of the worldwide population. Extraintestinal symptoms may be present as the first signs of CD, years before the CD diagnosis is made. A great variety of extraintestinal manifestations may be associated with CD. Cutaneous manifestations represent the main extraintestinal manifestations, with dermatitis herpetiformis being the most common in patients with CD. In adults, it has been demonstrated that the role of a gluten-free diet is crucial not only for the recovery of signs and symptoms associated with CD but also for cutaneous manifestations, which often improve after gluten avoidance. In children with CD, the association with skin disorders is well documented regarding dermatitis herpetiformis, but studies considering other dermatological conditions, such as psoriasis and atopic dermatitis, are few. The prevalence and manifestations of dermatological disorders in celiac children are often different from those in adults, explaining the gap between these populations. In addition, the therapeutic role of a gluten-free diet in the improvement in skin alterations is not fully understood in children and in adult population except for dermatitis herpetiformis. Therefore, cutaneous CD symptoms need to be known and recognized by physicians despite their specialties to improve early CD diagnosis, which is critical for a better prognosis. This review describes the current scientific evidence on skin manifestations associated with CD in the pediatric population.

Inflammatory bowel disease and psoriasis: modernizing the multidisciplinary approach

Psoriasis and inflammatory bowel disease (IBD) are immune-mediated diseases occurring in barrier organs whose main task is to protect the organism from attack. These disorders are highly prevalent especially in northern Europe where psoriasis has a prevalence of around 3-4% and IBD around 0.3%. The prevalence of IBD in North America has been estimated at around 0.4%. The total incidence rates in northern Europe have been estimated at around 6 for Crohn's disease and 11 for ulcerative colitis per 100 000 person-years, compared with an incidence rate of around 280 per 100 000 person-years for psoriasis. Both diseases are less common in countries with a lower index of development. The rise in IBD appears to occur as populations adopt a westernized lifestyle, whereas psoriasis seems more stable and prevalence differences may derive more from variation in genetic susceptibility. The gut microbiota is clearly an important driver of IBD pathogenesis; in psoriasis, changes in gut and skin microbiota have been reported, but it is less clear whether and how these changes contribute to the pathogenesis. Large studies show that most identified genes are involved in the immune system. However, psoriasis and IBD are highly heterogeneous diseases and there is a need for more precise and deeper phenotyping to identify specific subgroups and their genetic, epigenetic and molecular signatures. Epigenetic modifications of DNA such as histone modifications, noncoding RNA effects on transcription and translation and DNA methylation are increasingly recognized as the mechanism underpinning much of the gene-environment interaction in the pathogenesis of both IBD and psoriasis. Our understanding of underlying pathogenetic mechanisms has deepened fundamentally over the past decades developing hand in hand with novel therapies targeting pathways and proinflammatory cytokines incriminated in disease. There is not only substantial overlap between psoriasis and IBD, but also there are differences with implication for therapy. In psoriasis, drugs targeting interleukin-23 and interleukin-17 have shown superior efficacy compared with anti-TNFs, whilst in IBD, drugs targeting interleukin-17 may be less beneficial. The therapeutic toolbox for psoriasis is impressive and is enlarging also for IBD. Still, there are unmet needs reflecting the heterogeneity of both diseases and there is a need for closer molecular diagnostics to allow for the development of precise therapeutics.

Development of Dermatitis Herpetiformis in Chronic Plaque Psoriasis

Chronic plaque psoriasis is often associated with autoimmune bullous diseases. Dermatitis herpetiformis (DH) is a rare immunobullous disease that has been linked to celiac disease (CD). To our knowledge, the coexistence of psoriasis and DH is uncommon, and has only been described in anecdotal reports. We report a case of chronic plaque psoriasis complicated by DH in a 60-year-old patient with no known history of CD or associated symptoms. In our patient, DH presented atypically as multiple vesicles along the edges of psoriatic plaques located on the back and hips, and as vesiculobullous eruptions on the fingers. The patient was successfully treated with a combination of dapsone and a gluten-free diet for DH, and secukinumab for psoriasis. This case highlights the importance of screening for CD in patients with psoriasis, as well as other concomitant autoimmune diseases. A gluten-free diet should be trialled in psoriatic patients with positive CD serology.

The Effect of Antioxidant and Anti-Inflammatory Capacity of Diet on Psoriasis and Psoriatic Arthritis Phenotype: Nutrition as Therapeutic Tool?

Chronic inflammation and increased oxidative stress are contributing factors to many non-communicable diseases. A growing body of evidence indicates that dietary nutrients can activate the immune system and may lead to the overproduction of pro-inflammatory cytokines. Fatty acids as macronutrients are key players for immunomodulation, with n-3 polyunsaturated fatty acids having the most beneficial effect, while polyphenols and carotenoids seem to be the most promising antioxidants. Psoriasis is a chronic, immune-mediated inflammatory disease with multifactorial etiology. Obesity is a major risk factor for psoriasis, which leads to worse clinical outcomes. Weight loss interventions and, generally, dietary regimens such as gluten-free and Mediterranean diet or supplement use may potentially improve psoriasis’ natural course and response to therapy. However, data about more sophisticated nutritional patterns, such as ketogenic, very low-carb or specific macro- and micro-nutrient substitution, are scarce. This review aims to present the effect of strictly structured dietary nutrients, that are known to affect glucose/lipid metabolism and insulin responses, on chronic inflammation and immunity, and to discuss the utility of nutritional regimens as possible therapeutic tools for psoriasis and psoriatic arthritis.

Risk of Skin Disorders in Patients with Celiac Disease: A Population-Based Cohort Study

BACKGROUND AND AIMS

Although dermatitis herpetiformis is closely associated with celiac disease (CD), data on the relationship between CD and other dermatologic disorders have been mixed. We aimed to quantify the risk of skin disorders in patients after CD diagnosis in a population-based setting.

METHODS

Using data from all 28 pathology departments in Sweden 1969-2016, we identified patients with CD. Each patient was matched by age, sex, calendar year, and geographic region to up to 5 population controls. We calculated the risk of any skin disease and specific skin diseases using Cox proportional hazards.

RESULTS

We identified 43,300 patients with CD and 198,532 matched controls. After a median follow-up time of 11.4 years, the incidences of skin disease in CD patients and controls were 22.6 and 14.8 per 1000 person-years respectively (HR=1.55; 95%CI 1.51-1.58). Increased risks were present for eczema (HR=1.67; 95%CI 1.56-1.79), psoriasis (HR=1.55; 95%CI 1.43-1.68), urticaria (HR=1.52; 95% CI 1.42-1.64), vitiligo (HR=1.90; 95%CI 1.52-2.39), acne (HR=1.39; 95%CI 1.29-1.50), and alopecia areata (HR=1.78; 95%CI 1.43-2.20).

CONCLUSIONS

Compared to the general population, patients with CD are at increased risk of multiple common skin disorders, a risk that persists in the long-term.

The Risk of Systemic Diseases in Those with Psoriasis and Psoriatic Arthritis: From Mechanisms to Clinic

Psoriasis and psoriatic arthritis (PsA) have been recently considered as chronic systemic inflammatory disorders. Over the past decades, enormous evidence indicates that patients with psoriasis and PsA have a higher risk of developing various comorbidities including cardiovascular disease, metabolic disease, cancers, infections, autoimmune disease, and psychiatric diseases. However, reported risks of some comorbidities in those with psoriasis and PsA are somewhat different according to the research design. Moreover, pathomechanisms underlying comorbidities of those with psoriasis and PsA remain poorly elucidated. The purpose of this review is to provide the most updated comprehensive view of the risk of systemic comorbidities in those with psoriasis and PsA. Molecular mechanisms associated with the development of various comorbidities in those with psoriasis and PsA are also reviewed based on recent laboratory and clinical investigations. Identifying the risk of systemic comorbidities and its associated pathomechanisms in those with psoriasis and PsA could provide a sufficient basis to use a multi-disciplinary approach for treating patients with psoriasis and PsA.

Current Evidence on the Efficacy of Gluten-Free Diets in Multiple Sclerosis, Psoriasis, Type 1 Diabetes and Autoimmune Thyroid Diseases

In this review, we summarize the clinical data addressing a potential role for gluten in multiple sclerosis (MS), psoriasis, type 1 diabetes (T1D) and autoimmune thyroid diseases (ATDs). Furthermore, data on the prevalence of celiac disease (CD) and gluten-related antibodies in the above patient groups are presented. Adequately powered and properly controlled intervention trials investigating the effects of a gluten-free diet (GFD) in non-celiac patients with MS, psoriasis, T1D or ATDs are lacking. Only one clinical trial has studied the effects of a GFD among patients with MS. The trial found significant results, but it is subject to major methodological limitations. A few publications have found beneficial effects of a GFD in a subgroup of patients with psoriasis that were seropositive for anti-gliadin or deamidated gliadin antibodies, but no effects were seen among seronegative patients. Studies on the role of gluten in T1D are contradictive, however, it seems likely that a GFD may contribute to normalizing metabolic control without affecting levels of islet autoantibodies. Lastly, the effects of a GFD in non-celiac patients with ATDs have not been studied yet, but some publications report that thyroid-related antibodies respond to a GFD in patients with concomitant CD and ATDs. Overall, there is currently not enough evidence to recommend a GFD to non-celiac patients with MS, psoriasis, ATDs or T1D.