Autoimmune diseases involving skin and intestinal mucosa are more frequent in adolescents and young adults suffering from atopic dermatitis

Allergy and autoimmunity in children: non-mutually exclusive diseases. A narrative review

In last decades a simultaneous increase in the prevalence of atopic and autoimmune disorders in pediatric population has been observed. Despite the Th1-Th2 paradigm, supporting the polarization of the immune system with Th1 response involved in autoimmune diseases and Th2 response leading to hypersensitivity reactions, recent evidence suggests a possible coexistence of common pathogenic pathways as result of shared immune dysregulation. Similar genes and other mechanisms such as epithelial barrier damage, gut microbiota dysbiosis and reduced number of T regs and IL-10 contribute to the onset of allergy and autoimmunity. IgA deficiency is also hypothesized to be the crosslink between celiac disease and allergy by lowering gut mucous membrane protection from antigens and allergens. The present narrative review aims to give an overview of the co-occurrence of allergic and autoimmune disorders (celiac disease, inflammatory bowel diseases, type 1 diabetes mellitus, thyroid disease, juvenile idiopathic arthritis) in pediatric population, based on the available evidence. We also highlighted the common pathogenic pathways that may underpin both. Our findings confirm that allergic and autoimmune diseases are commonly associated, and clinicians should therefore be aware of the possible coexistence of these conditions in order to ameliorate disease management and patient care. Particular attention should be paid to the association between atopic dermatitis or asthma and celiac disease or type 1 diabetes and vice versa, for therapeutic interventions. Further studies are needed to better clarify mechanisms involved in the pathogenesis and eventually identify new therapeutic strategies.

Association of atopic dermatitis with autoimmune diseases: A bidirectional and multivariable two-sample mendelian randomization study

Background

Observational studies have suggested the association between atopic dermatitis (AD) and the risks of autoimmune diseases. It is still unclear, however, whether or in which direction causal relationships exist, because these associations could be confounded.

Objectives

Our study seeks to assess the possibility of AD as a cause of autoimmune diseases, and to estimate the magnitude of the causal effect.

Methods

Two-sample mendelian randomization (MR) analyses were performed using genome-wide association study (GWAS) summary-level statistics. Specifically, bidirectional MR analyses were conducted to examine the direction of association of AD with autoimmune diseases; multivariable MR analyses (MVMR1) were used to test the independence of causal association of AD with autoimmune diseases after controlling other atopic disorders (asthma and allergic rhinitis), while MVMR2 analyses were conducted to account for potential confounding factors such as smoking, drinking, and obesity. Genetic instruments for AD (Ncases=22 474) were from the latest GWAS meta-analysis. The GWAS summary data for asthma and allergic rhinitis were obtained from UK Biobank. The GWAS summary data for smoking, alcohol consumption, obesity and autoimmune diseases (alopecia areata, vitiligo, systemic lupus erythematosus, ankylosing spondylitis, rheumatoid arthritis, and type 1 diabetes) were selected from the largest GWASs available. Causal estimates were derived by the inverse-variance weighted method and verified through a series of sensitivity analyses.

Results

Genetically predicted AD linked to higher risks of rheumatoid arthritis (OR, 1.28; P=0.0068) (ORMVMR1, 1.65; P=0.0020) (ORMVMR2, 1.36; P<0.001), type 1 diabetes (OR, 1.37; P=0.0084) (ORMVMR1, 1.42; P=0.0155) (ORMVMR2, 1.45; P=0.002), and alopecia areata (OR, 1.98; P=0.0059) (ORMVMR1, 2.55; P<0.001) (ORMVMR2, 1.99; P=0.003) in both univariable and multivariable MR. These causal relationships were supported by sensitivity analyses. No causal effect of AD was identified in relation to systemic lupus erythematosus, vitiligo, and ankylosing spondylitis. Concerning the reverse directions, no significant association was noted.

Conclusion

The results of this MR study provide evidence to support the idea that AD causes a greater risk of rheumatoid arthritis, type 1 diabetes and alopecia areata. Further replication in larger samples is needed to validate our findings, and experimental studies are needed to explore the underlying mechanisms of these causal effects.

Childhood blood eosinophils and symptoms of allergic disorders: a cross-sectional study in Southern China

PURPOSE

The relationship between childhood blood eosinophils and subtypes of allergic diseases remains understudied. This study aimed to examine the associations between childhood blood eosinophils and subtypes of asthma, rhinitis and dermatitis, as well as the modifying effect of age.

METHODS

We obtained concurrent blood cell counts and serum Immunoglobulin E (IgE) test results in 5026 children (0-13, years) from First Affiliated Hospital of Guangzhou Medical University from 2014 to 2019. Generalized additive models with multivariable adjustments were utilized to model the exposure-response relationship between eosinophils and allergic symptoms. The robustness of the association was assessed in two age categories (<6, 6-13 years).

RESULTS

The association of eosinophils with allergic asthma/rhinitis was positively nonlinear, with a plateau at levels of Q₄ (≥0.51, 10⁹/L). Conversely, exposure-response curves between eosinophils and the risk of non-allergic asthma and rhinitis were negatively linear, and especially, became statistically significant when levels of eosinophils were larger than Q₃ (≥0.30, 10⁹/L). Compared with their counterparts, school-aged children (6-13, years) with a higher level of blood eosinophils (≥0.35, 10⁹/L) were more likely to suffer from allergic asthma [relative excess risk due to interaction (RERI), 2.51; 95% CI, 1.24-3.78], allergic rhinitis (RERI, 2.79; 95% CI, 1.14-4.45) but not allergic dermatitis (RERI not significant).

CONCLUSION

Higher eosinophil counts were associated with the increased risk of allergic subtype symptoms and the decreased risk of non-allergic subtypes in children. Moreover, the associations between eosinophils and allergic asthma/rhinitis were accentuated in the school-aged child. These findings may contribute to providing novel insights for clinical administration relevance of allergic-related symptoms.Key messages:There was a positively nonlinear association between childhood eosinophils and allergic asthma/rhinitis.Age modified the associations between eosinophils and allergy-related outcomes. The associations of eosinophil with allergic asthma/rhinitis accentuated in the school-aged child (6-13, years).

Correlations of thyroid autoantibodies with allergic diseases: A case-control study of 434 Chinese patients

There is growing interest in the relationship between allergies and autoimmune diseases, although previous studies have yielded inconsistent results. The thyroglobulin (Tg)/thyroid peroxidase antibody (TPOAb) group consisted of 217 patients with positive thyroglobulin antibody (TgAb) and/or TPOAb test results. Another set of 217 age- and sex-matched individuals with both TgAb- and TPOAb-negative results were selected as control group. History of allergic rhinitis (AR), chronic spontaneous urticaria (CSU), and/or atopic dermatitis (AD) was elicited before autoantibody detection. The association of thyroid autoantibodies with allergic diseases was assessed using univariate and multivariate logistic regression analysis, and the results were reported as odds ratios (ORs). TgAb positivity (OR, 2.333) was identified as a risk factor for AR, AD, or CSU in Chinese patients, suggesting the involvement of thyroid autoantibodies in the pathogenesis of atopic reactions. Multivariate regression analysis also confirmed that the presence of TgAb (P = .004), rather than TPOAb (P = .468), had a significant impact on the occurrence of allergic disease. Physicians should carefully monitor atopic symptoms in individuals with elevated TgAb or TPOAb levels to reduce the risk of allergic diseases, such as AR, AD, and CSU.

Atopic dermatitis and risk of autoimmune conditions: Population-based cohort study

BACKGROUND

Atopic dermatitis (AD) is associated with immune dysregulation, but epidemiologic data on the pattern of autoimmune comorbidity in people with AD are limited.

OBJECTIVE

We sought to determine the risk of autoimmune conditions in people newly diagnosed with AD.

METHODS

Retrospective cohort analysis (January 2009 to December 2018), using the UK-based Oxford-Royal College of General Practitioners Research and Surveillance Centre primary care database. We compared baseline prevalence and incidence after diagnosis of autoimmune conditions in 173,709 children and adults with new-onset AD and 694,836 age-, sex-, and general practitioner practice-matched controls. Outcomes were a composite of any autoimmune condition (Crohn disease, ulcerative colitis, celiac disease, pernicious anemia, type 1 diabetes, autoimmune hypothyroidism, Graves disease, psoriatic arthritis, rheumatoid arthritis, ankylosing spondylitis, systemic lupus erythematosus, Sjögren syndrome, vitiligo, alopecia areata, and multiple sclerosis) and each individual autoimmune condition.

RESULTS

Preexisting autoimmune conditions were more common in people diagnosed with AD compared to controls (composite 5.8% vs 4.3%). Excluding people with preexisting autoimmune disease, there was an association between AD and incidence of new-onset autoimmune disease (composite adjusted hazard ratio [aHR] 1.28; 95% confidence interval [CI] 1.23-1.34). Risk was highest for more severe AD (aHR 1.99; 95% CI 1.77-2.23) than moderate AD (aHR 1.33; 95% CI 1.19-1.49) or mild AD (aHR 1.22; 95% CI 1.16-1.28). People with AD were at significantly increased risk of developing psoriatic arthritis, Sjögren syndrome, Crohn disease, vitiligo, alopecia areata, pernicious anemia, ulcerative colitis, rheumatoid arthritis, and hypothyroidism (aHR range 1.17-2.06), but not other autoimmune conditions.

CONCLUSION

People with AD have an increased risk of multiple autoimmune conditions, especially those with more severe AD.

What are the highest yielding search strategy terms for systematic reviews in atopic dermatitis? A systematic review

The impact of search strategies on systematic reviews (SR) of atopic dermatitis (AD) is unknown. The purpose of this review was to evaluate search strategies used in SR of AD and their impact on the frequency of manuscripts identified. MEDLINE and EMBASE were searched for SR related to AD. Simulations were performed by running combinations of search terms in MEDLINE and EMBASE. Overall, 250 SR met inclusion criteria, of which 225 specified search strategies. SR using 5-6 terms (20.0% to 12.1%) or ≥ 7 (40.0% to 18.8%) terms decreased, whereas SR using 3-4 terms numerically increased (18.8% to 30.2%) and 1-2 terms remained similar (37.5% to 38.9%) from 1999-2009 to 2015-2019. The most commonly searched terms were "atopic dermatitis" (n = 166), followed by "eczema" (n = 156), "dermatitis atopic'" (n = 81), "atopic eczema" (n = 74), "neurodermatitis" (n = 59), "Besniers prurigo" (n = 29), "infantile eczema" (n = 27), and "childhood eczema" (n = 19). Simulations revealed that "eczema" and "atopic dermatitis" yielded the most hits. The number of search terms that maximized hits in MEDLINE and EMBASE was 5 and 4, respectively. Search strategies for AD were heterogeneous, with high proportions of search strategies providing few search hits. Future studies should use standardized and optimized search terms.

Atopic Diseases Are Associated With Development of Inflammatory Bowel Diseases in Korea: A Nationwide Population-based Study

BACKGROUND & AIMS

The association between atopic diseases and inflammatory bowel diseases (IBD) is unclear. We conducted a nationwide population-based study in Korea to investigate the effect of atopic diseases on the development of IBD.

METHODS

A total of 9,923,521 participants, who received a medical check-up in 2009, were included and followed through 2017. The presence of any atopic diseases, including atopic dermatitis (AD), allergic rhinitis (AR), and asthma, was evaluated. Patients who developed IBD, including Crohn's disease (CD) and ulcerative colitis (UC), were identified using claims data from National Health Insurance; the association between atopic diseases and the risk of IBD was evaluated using Cox proportional hazard models, and presented as adjusted hazard ratios (aHRs) with 95% CIs.

RESULTS

During a mean follow-up period of 7.3 years, 1419 patients (0.014%) developed CD and 5897 patients (0.059%) developed UC. The incidences of CD (per 100,000 person-years) were 3.756, 2.248, and 2.346 in patients with AD, AR, or asthma, respectively. The incidences of UC were 11.952, 9.818, and 9.358 in patients with AD, AR, or asthma, respectively. Multivariable analysis revealed that the aHRs for incident CD in patients with AD, AR, or asthma were 2.02, 1.33, and 1.60 (95% CIs, 1.118-3.663, 1.149-1.529, and 1.193-2.136, respectively) compared with controls. The risks of incident UC in patients with AD, AR, or asthma were 1.51, 1.32, and 1.29 (95% CIs, 1.082-2.104, 1.229-1.410, and 1.115-1.491, respectively) compared with controls. Moreover, an increase in the number of atopic diseases gradually increased the risk for CD and UC; for 1 or 2 or more atopic diseases, the aHRs for CD were 1.35 and 1.65 (95% CIs, 1.171-1.560 and 1.146-2.376), and the aHRs for UC were 1.30 and 1.49 (95% CIs, 1.211-1.392 and 1.249-1.774), respectively.

CONCLUSIONS

Based on a nationwide population-based study in Korea, patients with any atopic disease, including AD, AR, or asthma, have an increased risk for CD and UC. The risk for IBD increases with the increase in the number of atopic diseases.

Could it be gluten? Additional skin conditions associated with celiac disease

Celiac disease is a multifactorial, inflammatory disorder initiated and sustained by the ingestion of gluten. Occurring across a broad population, the intestinal and extraintestinal manifestations of celiac disease are variable in severity and may be nonspecific in presentation. Given that environmental, genetic, and immune factors involved in the pathogenesis of celiac disease that the digestive tract and skin share many characteristics, and with a prevalence of 0.5-1% in most populations, it is reasonable to consider varying presentations of skin conditions that are linked with celiac disease. The association between celiac disease and skin conditions has been discussed earlier, but new studies have emerged suggesting cutaneous involvement in addition to dermatitis herpetiformis. We review the current literature identifying the relationship and potential mechanisms between celiac disease and various skin conditions.

Short-term exposure to ambient air pollution and hospital visits for IgE-mediated allergy: A time-stratified case-crossover study in southern China from 2012 to 2019

BACKGROUND

Because of the limited epidemiological evidence on the association between acute air pollutants and allergy, there is a need to investigate this association, especially between the short-term exposure to air pollution and the serum Immunoglobulin E (IgE)-mediated allergy.

METHODS

A total of 39,569 IgE test results and demographic characteristics were obtained in the First Affiliated Hospital of Guangzhou Medical University between August 2012 and September 2019. Ninety-nine specific allergens were tested according to clinical diagnosis. The logistic regression was used to assess the effects of CO, NO₂ and PM_2.5 exposure on the risk of sensitization to specific inhalant/food allergens. Generalized additive models with multivariate adjustments were utilized to model the exposure-response relationship. Stratified analyses were performed to estimate the reliability of correlations in various subgroups.

FINDINGS

Single-pollutant models indicate that the 3-day moving average (lag_2-4) of CO, PM_2.5 or NO₂ is associated with the increased risk for allergic diseases related to specific inhaled allergens. In multi-pollutant models, the adjusted Odds Ratio (OR) 95% (Confidence Interval, CI) increases by 8% (95% CI, 2%-15%) for per increment of 0.2 mg/m³ in CO levels, and rises by 8% (95% CI, 2%-13%) for each increase of 16.3 μg/m³ in PM_2.5 concentration. The associations are stronger in youngsters (<18, years) but not significantly different by gender. Particularly, a significantly stronger association between PM_2.5 exposure and hospital visits for inhaled allergy is observed in patients who are exposed to lower concentration of SO₂ (<10.333 μg/m³) and higher levels of NO₂ (≥42.0 μg/m³), as well as patients enrolled after 2017.

INTERPRETATION

The short-term exposure to CO/PM_2.5 increases the number of hospital visits for IgE-mediated allergy, especially for the sensitization to specific inhalant allergens. Therefore, to prevent inhaled allergies, the public policy for controlling air pollution needs to be considered seriously.

FUNDING

This study was supported by the University of Macau (grant numbers: FHS-CRDA-029-002-2017 and MYRG2018-00,071-FHS) as well as the Science and Technology Development Fund, Macau SAR (File no. 0004/2019/AFJ and 0011/2019/AKP). This work was also supported by the National Natural Science Foundation of China (81,871,736), the National Key Technology R&D Program (2018YFC1311902), the Guangdong Science and Technology Foundation (2019B030316028), the Guangzhou Municipal Health Foundation (20191A011073), and the Guangzhou Science and Technology Foundation (201,804,020,043).

Associations of self-reported atopic dermatitis with comorbid conditions in adults: a population-based cross-sectional study

Background

The objective of this study was to investigate the relationships between atopic dermatitis (AD) and other common chronic health conditions in adults.

Methods

A cross-sectional survey was sent to a randomly selected population sample of 78,004 adults in Sweden. The questionnaires included measures of self-reported physical and mental health. Binary and multinomial logistic regression were used to examine the associations of AD with common chronic health conditions and psychological wellbeing.

Results

AD was self-reported by 4,175 respondents, representing almost 14% of the study population of 34,313 adults. Our results showed positive associations between AD and chronic health disorders, including conditions of the oral cavity: chronic obstructive pulmonary disease (adjusted odds ratio [aOR] = 1.58, 95% confidence interval [CI]: 1.30 to 1.92), asthma (aOR = 2.13, 95% CI: 1.91 to 2.38), mild recurrent gastrointestinal symptoms (adjusted relative risk ratio [aRRR] = 1.78, 95% CI: 1.64 to 1.92), high blood pressure (aOR = 1.16, 95% CI: 1.06 to 1.26), obesity (aOR = 1.34, 95% CI: 1.23 to 1.47), mild joint pain (aRRR = 1.47, 95% CI: 1.35 to 1.61), mild headache or migraine (aRRR = 1.50, 95% CI: 1.38 to 1.64), caries (aOR = 1.25, 95% CI: 1.04 to 1.49), bleeding gums (aOR = 1.69, 95% CI: 1.38 to 2.08), periodontitis (aOR = 1.42, 95% CI: 1.13 to 1.77), sensitive teeth (aOR = 1.57, 95% CI: 1.35 to 1.82), and dry mouth (aOR = 1.52, 95% CI: 1.33 to 1.74). Adjustment for asthma and depression attenuated the magnitude of the associations between AD and the study outcomes. AD was also associated with poorer general psychological wellbeing.

Conclusions

Adults reporting AD may be at increased risk of chronic disorders and decreased psychological wellbeing. Physicians should recognize that individuals with severe AD and those with comorbid asthma or depression may be especially vulnerable.

Association between atopic dermatitis and autoimmune diseases: a population-based case-control study

Background

Atopic dermatitis (AD) is a common chronic skin disorder and is well known to be associated with other atopic conditions. There is increasing evidence for an association also with nonatopic conditions, including autoimmune diseases, but data are limited about several autoimmune diagnoses.

Objectives

To investigate the association between AD and autoimmune diseases.

Methods

This case–control study used Swedish national healthcare registers. The source population comprised the entire Swedish population aged ≥ 15 years from 1968 to 2016. Cases, including all those with an inpatient diagnosis of AD (from 1968) and/or a specialist outpatient diagnosis of AD (from 2001), were matched by sex and age to healthy controls (104 832 cases of AD, 1 022 435 controls).

Results

AD was significantly associated with one or more autoimmune diseases compared with controls – adjusted odds ratio (aOR) 1·97, 95% confidence interval (CI) 1·93–2·01 – and this association was significantly stronger in the presence of multiple autoimmune diseases compared with only one. The association was strongest for autoimmune disorders involving the skin (aOR 3·10, 95% CI 3·02–3·18), the gastrointestinal tract (aOR 1·75, 95% CI 1·69–1·82) or connective tissue (aOR 1·50, 95% CI 1·42–1·58). In the overall analysis, men with AD had a stronger association with rheumatoid arthritis and coeliac disease than did women with AD. In subanalyses, the findings remained stable in multivariable analyses after adjustment for smoking and parental autoimmune disease.

Conclusions

This large population‐based study indicates significant autoimmune comorbidity of adults with AD, especially between AD and autoimmune dermatological, gastrointestinal and rheumatological diseases. Having multiple autoimmune diseases resulted in a stronger association with AD than having only one autoimmune disease.

What is already known about this topic?

Atopic dermatitis (AD) is one of the most common chronic inflammatory skin diseases.

Some studies have shown that AD is associated with some autoimmune diseases, such as Crohn disease, ulcerative colitis, coeliac disease, alopecia areata and vitiligo, but data are limited for several major autoimmune diagnoses.

What does this study add?

In this study, AD was associated with several autoimmune diseases, especially those involving the skin, the gastrointestinal tract or connective tissue.

The association was stronger for individuals with multiple autoimmune comorbidities.

Linked Comment: J.I. Silverberg. Br J Dermatol 2021; 185:243–244.

Plain language summary available online

Atopic dermatitis. Interdisciplinary diagnostic and therapeutic recommendations of the Polish Dermatological Society, Polish Society of Allergology, Polish Pediatric Society and Polish Society of Family Medicine. Part I. Prophylaxis, topical treatment and phototherapy

Atopic dermatitis is a chronic and recurrent inflammatory dermatosis with concomitant intensive pruritus, and is diagnosed both in children and adults. Atopic dermatitis-patients are predisposed to have bacterial, viral and fungal skin infections; they also suffer from an increased risk of developing food allergies (especially, at an infantile age), allergic rhinitis, or bronchial asthma (a so-called atopic march). Currently, an increasing atopic dermatitis incidence constitutes a serious medical problem that regards not only dermatology and allergology, but also paediatrics, and family medicine. The basis for atopic dermatitis treatment and prophylaxis is restoration of epidermal barrier functions by means of tailored emollients. Atopic dermatitis therapies should effectively eliminate clinical symptoms of the disease, prevent exacerbations as well as complications, and improve patients' quality of life.

Atopic Dermatitis and Celiac Disease: A Cross-Sectional Study of 116,816 Patients

BACKGROUND

Both atopic dermatitis and celiac disease are often accompanied by other immune-mediated disorders.

OBJECTIVE

The objective of this study was to evaluate the potential association between atopic dermatitis and celiac disease in a broad community-based population.

METHODS

A cross-sectional observational design was used. Demographic and clinical data were collected for patients enrolled in a large health management organization who were diagnosed with atopic dermatitis by a dermatologist in 2002-17. The presence of celiac disease/celiac disease-related morbidities was recorded for the whole group, for adults (age > 18 years), and for adults with moderate-to-severe atopic dermatitis. Findings were compared with a matched control group without atopic dermatitis.

RESULTS

The study group included 116,816 patients of whom 45,157 were adults; 1909 adult patients had moderate-to-severe atopic dermatitis. Compared to the respective control subjects, the prevalence rate of celiac disease in the whole group was 0.6% vs. 0.4%; in the adults, 0.6% vs. 0.3%; and in the adults with moderate-to-severe atopic dermatitis, 0.8% vs. 0.3% (p < 0.001 for all). On multivariate analysis, atopic dermatitis was associated with a significantly higher prevalence of celiac disease (odds ratio = 1.609, 95% confidence interval 1.42-1.82, p < 0.001) in the entire study population and each subgroup.

CONCLUSIONS

We observed a significant association between atopic dermatitis and celiac disease. This association emphasizes the need for timely screening of gastrointestinal morbidities in individuals with atopic dermatitis to prevent long-term complications.

The Bidirectional Association between Inflammatory Bowel Disease and Atopic Dermatitis: A Systematic Review and Meta-Analysis

<b><i>Background:</i></b> Previous investigations have suggested a significant association between inflammatory bowel disease (IBD) and atopic dermatitis (AD). Yet, outcomes published remain inconsistent. <b><i>Objective:</i></b> To explore the association between IBD and AD by a systematic review and meta-analysis. <b><i>Methods:</i></b> A comprehensive search of studies published from March 1, 1968, to July 26, 2019, was performed in electronic databases as follows: PubMed, Embase, Cochrane Library, and Web of Science. Methodological quality was assessed based on the Newcastle-Ottawa Scale. Data analysis was conducted using R version 3.6.1 (meta package version 4.9-7). <b><i>Results:</i></b> A total of 14 studies were eligible for exploring the association between IBD and AD. Statistically significant differences were found on the risk of AD comorbidity among patients with IBD (risk ratio [RR] 1.83, 95% CI 1.39–2.40), Crohn’s disease (CD; RR 2.06, 95% CI 1.61–2.64), and ulcerative colitis (UC; RR 1.66, 95% CI 1.23–2.24). Compared with non-AD subjects, patients with AD were 48% (<i>p</i> = 0.019), 44% (<i>p</i> = 0.002), and 38% (<i>p</i> = 0.000) more likely to exhibit IBD, CD as well as UC, respectively. <b><i>Discussion:</i></b> Our evidence supported a significant bidirectional association between IBD and AD. Future prospective studies are warranted to explore underlying mechanisms linking them.

[Atopic dermatitis and general medical comorbidities]

Atopic dermatitis (AD) is one of the most frequent chronic inflammatory skin diseases, characterized by pruritic eczematous lesions. Due to the fact that AD is accompanied by signs of systemic inflammation and that an increased number of novel systemic treatment options are currently emerging, research into general medical comorbidities in moderately to severely affected AD patients has received great impetus in recent years. These studies have confirmed an increased risk of atopic diseases such as allergic asthma in AD patients. Furthermore, an association between AD and dermatological diseases with autoimmune pathophysiology such as vitiligo and alopecia areata has been demonstrated. Moreover, several studies have revealed an increased risk for internal autoimmune diseases in AD patients, e.g. inflammatory bowel disease and rheumatoid arthritis. A differentiated view of the data on AD as a possible risk factor for cardiovascular disease is needed. Large cross-sectional studies in the US revealed a correlation between AD and cardiovascular comorbidities. This has not been confirmed as yet in large German, Danish and Canadian investigations. Whether diverse "coping" strategies in different countries can explain these variances remains to be discussed. In terms of microbial comorbidities, AD patients display a particular susceptibility to viral infections.

The IL-13-OVOL1-FLG axis in atopic dermatitis

Despite sharing interleukin-4 receptor α (IL-4Rα) in their signaling cascades, IL-4 and IL-13 have different functions in atopic inflammation. IL-13 preferentially participates in the peripheral tissues because tissue-resident group 2 innate lymphoid cells produce IL-13 but not IL-4. In contrast, lymph node T follicular helper cells express IL-4 but not IL-13 to regulate B-cell immunity. The dominant microenvironment of IL-13 is evident in the lesional skin of atopic dermatitis (AD). The IL-13-rich local milieu causes barrier dysfunction by down-regulating the OVOL1-filaggrin (FLG) axis and up-regulating the periostin-IL-24 axis. Genome-wide association studies also point to the crucial involvement of the IL-13, OVOL1 and FLG genes in the pathogenesis of AD. Biologics targeting IL-13, such as the anti-IL-4Rα antibody dupilumab and the anti-IL-13 antibody tralokinumab, successfully improve AD lesions and further highlight the importance of IL-13 in the pathogenesis of AD.

Current therapeutic paradigm in pediatric atopic dermatitis: Practical guidance from a national expert panel

INTRODUCTION AND OBJECTIVES

Atopic dermatitis (AD) is the most common cutaneous inflammatory disease in both adults and children. Although emerging therapeutic approaches are being investigated for the management of pediatric AD, it still needs to be managed with conventional treatments. This consensus document is aimed at providing an update on general management and therapies of pediatric AD, defining practical recommendations for using both topical and systemic agents.

MATERIAL AND METHODS

A panel of experts consisting of dermatologists and pediatricians were convened in order to define statements, through a Delphi process, standardizing the management of AD in pediatric subjects in a real-world setting.

RESULTS

A set of practical recommendations obtaining an at least 75% agreement was presented.

CONCLUSIONS

This set of practical recommendations represents a simple and fast snapshot on the pediatric use of common anti-AD therapeutics.

Is probiotic use beneficial for skin lesions in patients with inflammatory bowel disease?

Background: Inflammatory bowel diseases (IBDs) are associated with extraintestinal manifestations including skin lesions. The intestinal microflora plays a key role in the development and course of IBD. Aim: To examine the efficacy of probiotics and the occurrence of skin lesions in patients with IBD. Methods: The occurrence of cutaneous lesions in IBD patients from Northern Sardinia was analyzed according to demographic, anthropometrics, clinical features, treatments, and probiotic use expressed as the ratio of disease duration under probiotic treatment and the total disease duration. Results: In 170 IBD patients (59.4% women; UC: 61.2%) at least one skin lesion was present (8.2%) at diagnosis and in 30.6% developed during the follow-up. Psoriasis, erythema nodosum, and pyoderma gangrenosum were the most frequent. An inverse trend was observed between probiotics use and skin lesions occurrence after adjusting for confounders, including conventional treatment for IBD. The risk of developing at least one skin lesion was 1.40 for probiotic use between 5-19% of disease duration and 0.3 for probiotic use > 50%. Body mass index, Crohn phenotype, marriage, and potency of IBD-treatment were significant predictors for developing skin lesions. Conclusion: These findings suggest that probiotics may be an additional tool in the treatment of IBD.

Skin diseases associated with atopic dermatitis

Atopic dermatitis is a common chronic pruritic inflammatory skin disorder, characterized by an abnormal skin barrier, immune dysfunction, and an altered skin microbiome. Atopic dermatitis may be seen in conjunction with a variety of other skin disorders due to the complex pathogenesis of atopic dermatitis, involving genetic and environmental factors that are associated with immune dysfunction, barrier defects, and altered skin microbiomes. Skin disorders associated with atopic dermatitis include diseases sharing similar genetic origins like ichthyosis vulgaris, infectious diseases such as impetigo, and eczema herpeticum, in addition to the cutaneous autoimmune diseases, alopecia areata, and vitiligo. Atopic dermatitis is also often linked to such benign conditions as pityriasis alba and keratosis pilaris. This review discusses the cutaneous comorbidities of atopic dermatitis and their relationship via their occurrence in conjunction with atopic dermatitis.

Burden of atopic dermatitis in Japanese adults: Analysis of data from the 2013 National Health and Wellness Survey

Atopic dermatitis is a chronic inflammatory skin disease. The objective of this study was to characterize the burden of atopic dermatitis in Japanese adult patients relative to the general population. Japanese adults (≥18 years) with a self-reported diagnosis of atopic dermatitis and adult controls without atopic dermatitis/eczema/dermatitis were identified from the 2013 Japan National Health and Wellness Survey. Atopic dermatitis patients were propensity-score matched with non-atopic dermatitis controls (1:2 ratio) on demographic variables. Patient-reported outcome data on comorbidities, mood and sleep disorders, health-related quality of life, work productivity and activity impairment, and health-care resource utilization were analyzed in atopic dermatitis patients and matched controls. A total of 638 Japanese adult patients with atopic dermatitis were identified, of whom 290 (45.5%) rated their disease as "moderate/severe" and 348 (54.5%) as "mild". The analysis cohort comprised 634 atopic dermatitis patients and 1268 matched controls. Atopic dermatitis patients reported a significantly higher prevalence of arthritis, asthma, nasal allergies/hay fever, anxiety, depression and sleep disorders compared with controls (all P < 0.001). Atopic dermatitis patients also reported a significantly poorer health-related quality of life, higher overall work and activity impairment, and higher health-care resource utilization (all P < 0.001). Self-rated disease severity was not associated with disease burden, except for a significantly higher overall work and activity impairment. In conclusion, Japanese adult patients with atopic dermatitis reported a substantial disease burden relative to adults without atopic dermatitis, suggesting an unmet need for effective strategies targeting disease management.

Eosinophils from Physiology to Disease: A Comprehensive Review

Despite being the second least represented granulocyte subpopulation in the circulating blood, eosinophils are receiving a growing interest from the scientific community, due to their complex pathophysiological role in a broad range of local and systemic inflammatory diseases as well as in cancer and thrombosis. Eosinophils are crucial for the control of parasitic infections, but increasing evidence suggests that they are also involved in vital defensive tasks against bacterial and viral pathogens including HIV. On the other side of the coin, eosinophil potential to provide a strong defensive response against invading microbes through the release of a large array of compounds can prove toxic to the host tissues and dysregulate haemostasis. Increasing knowledge of eosinophil biological behaviour is leading to major changes in established paradigms for the classification and diagnosis of several allergic and autoimmune diseases and has paved the way to a "golden age" of eosinophil-targeted agents. In this review, we provide a comprehensive update on the pathophysiological role of eosinophils in host defence, inflammation, and cancer and discuss potential clinical implications in light of recent therapeutic advances.