How atopic is atopic dermatitis?

Emollient application from birth to prevent eczema in high-risk children: the BEEP RCT

Background

Atopic eczema is a common childhood skin problem linked with asthma, food allergy and allergic rhinitis that impairs quality of life.

Objectives

To determine whether advising parents to apply daily emollients in the first year can prevent eczema and/or other atopic diseases in high-risk children.

Design

A United Kingdom, multicentre, pragmatic, two-arm, parallel-group randomised controlled prevention trial with follow-up to 5 years.

Setting

Twelve secondary and four primary care centres.

Participants

Healthy infants (at least 37 weeks' gestation) at high risk of developing eczema, screened and consented during the third trimester or post delivery.

Interventions

Infants were randomised (1 : 1) within 21 days of birth to apply emollient (Doublebase Gel®; Dermal Laboratories Ltd, Hitchin, UK or Diprobase Cream®) daily to the whole body (excluding scalp) for the first year, plus standard skin-care advice (emollient group) or standard skin-care advice only (control group). Families were not blinded to allocation.

Main outcome measures

Primary outcome was eczema diagnosis in the last year at age 2 years, as defined by the UK Working Party refinement of the Hanifin and Rajka diagnostic criteria, assessed by research nurses blinded to allocation. Secondary outcomes up to age 2 years included other eczema definitions, time to onset and severity of eczema, allergic rhinitis, wheezing, allergic sensitisation, food allergy, safety (skin infections and slippages) and cost-effectiveness.

Results

One thousand three hundred and ninety-four newborns were randomised between November 2014 and November 2016; 693 emollient and 701 control. Adherence in the emollient group was 88% (466/532), 82% (427/519) and 74% (375/506) at 3, 6 and 12 months. At 2 years, eczema was present in 139/598 (23%) in the emollient group and 150/612 (25%) in controls (adjusted relative risk 0.95, 95% confidence interval 0.78 to 1.16; p = 0.61 and adjusted risk difference -1.2%, 95% confidence interval -5.9% to 3.6%). Other eczema definitions supported the primary analysis. Food allergy (milk, egg, peanut) was present in 41/547 (7.5%) in the emollient group versus 29/568 (5.1%) in controls (adjusted relative risk 1.47, 95% confidence interval 0.93 to 2.33). Mean number of skin infections per child in the first year was 0.23 (standard deviation 0.68) in the emollient group versus 0.15 (standard deviation 0.46) in controls; adjusted incidence rate ratio 1.55, 95% confidence interval 1.15 to 2.09. The adjusted incremental cost per percentage decrease in risk of eczema at 2 years was £5337 (£7281 unadjusted). No difference between the groups in eczema or other atopic diseases was observed during follow-up to age 5 years via parental questionnaires.

Limitations

Two emollient types were used which could have had different effects. The median time for starting emollients was 11 days after birth. Some contamination occurred in the control group (< 20%). Participating families were unblinded and reported on some outcomes.

Conclusions

We found no evidence that daily emollient during the first year of life prevents eczema in high-risk children. Emollient use was associated with a higher risk of skin infections and a possible increase in food allergy. Emollient use is unlikely to be considered cost-effective in this context.

Future research

To pool similar studies in an individual patient data meta-analysis.

Trial registration

This trial is registered as ISRCTN21528841.

Funding

This award was funded by the National Institute for Health and Care Research (NIHR) Health Technology Assessment programme (NIHR award ref: 12/67/12) and is published in full in Health Technology Assessment; Vol. 28, No. 29. See the NIHR Funding and Awards website for further award information.

Decreasing prevalence of atopic dermatitis in Swedish schoolchildren: three repeated population-based surveys

BACKGROUND

The prevalence of atopic dermatitis (AD) has increased over several decades and now affects about one-fifth of all children in high-income countries (HICs). While the increase continues in lower-income countries, the prevalence of AD might have reached a plateau in HICs.

OBJECTIVES

To investigate trends in the prevalence of AD and atopic comorbidity in schoolchildren in Sweden.

METHODS

The study population consisted of three cohorts of children (median age 8 years) in Norrbotten, Sweden, for 1996 (n = 3430), 2006 (n = 2585) and 2017 (n = 2785). An identical questionnaire that included questions from the International Study of Asthma and Allergies in Childhood (ISAAC) protocol was used in all three cohorts. Trends in AD prevalence were estimated, as well as trends in atopic comorbidity. AD prevalence was estimated both according to the ISAAC definition of AD and by adding the reported diagnosis by a physician (D-AD).

RESULTS

The prevalence of AD decreased in the last decade, from 22.8% (1996) and 21.3% (2006) to 16.3% (2017; P < 0.001). The prevalence of D-AD was lower, but the same pattern of decrease was seen, from 9.3% (1996) and 9.4% (2006) to 5.7% (2017; P < 0.001). In all three cohorts, AD was more common among girls than boys (18.9% vs. 13.8% in 2017; P < 0.001). Children from the mountain inlands had a higher prevalence of AD than children from coastal cities (22.0% vs. 15.1% in 2017; P < 0.001). In comparing D-AD, there were no significant differences between the sexes or between inland or coastal living. Concomitant asthma increased over the years from 12.2% (1996) to 15.8% (2006) to 23.0% (2017; P < 0.001). Concomitant allergic rhinitis and allergic sensitization increased from 1996 (15.0% and 27.5%) to 2006 (24.7% and 49.5%) but then levelled off until 2017 (21.0% and 46.7%).

CONCLUSIONS

The prevalence of AD among schoolchildren in Sweden decreased over the study period, whereas atopic comorbidity among children with AD increased. Although a decrease was seen, AD is still common and the increase in atopic comorbidity among children with AD, especially the increase in asthma, is concerning.

Fungal allergen sensitization: Prevalence, risk factors, and geographic variation in the United States

BACKGROUND

Many fungal species are associated with the pathogenesis of allergic disease, yet most epidemiologic studies on IgE-mediated fungal sensitization have only included a few species.

OBJECTIVE

We investigated fungal allergen sensitization prevalence, risk factors, and geographic variation in the United States.

METHODS

From 2014 to 2019, a total of 7,912,504 serum-specific IgE (sIgE) test results for 17 fungal species were measured in 1,651,203 patients aged 0-85 years by a US-wide clinical laboratory. Fungal sensitization prevalence, patterns, and relationship with demographic characteristics, clinical diagnoses, and geographic regions were analyzed.

RESULTS

Twenty-two percent of patients were positive (sIgE > 0.10 kUA/L) to at least 1 fungal allergen; 13.7% were positive to >2 fungal allergens. Fungal species-specific positivity rates ranged 7.4-18.6% and were highest for Candida albicans (18.6%), Alternaria alternata (16.6%), Stemphylium herbarum (14.9%), and Aspergillus fumigatus (14.2%). Other fungi that were frequently tested had relatively low positivity rates (eg, Cladosporium herbarum 11.1%, Penicillium chrysogenum 10.7%). Independent risk factors for test positivity for all fungal species included male sex, teen age (highest in those aged 10-19 years), atopic dermatitis, and asthma. Fungal sensitization was generally higher in urban areas and ecoregions composed predominantly of grasslands and prairies compared to woodlands and forest, although there was greater variation in sensitization risk to different fungi in different ecoregions.

CONCLUSION

Independent risk factors for fungal sensitization include male sex, teen ages, atopic dermatitis, asthma, and ecoregion.

Clinical Approach to Patients with Moderate-to-Severe Atopic Dermatitis: A Spanish Delphi Consensus

Despite emerging evidence and advances in the management of atopic dermatitis there a lack of consensus regarding the diagnostic criteria, therapeutic approach, method to assess severity, and patient follow-up for this condition. An expert consensus study was conducted to provide recommendations on the management of patients with moderate-to-severe atopic dermatitis. The study used Delphi-like methodology based on a literature review, a summary of the scientific evidence, and a 2-round survey. The agreement of 60 panellists on 21 statements was evaluated. Consensus was pre-defined as ≥ 80% agreement of all respondents. In the first round 6 statements reached consensus. Unanimous consensus was achieved regarding therapeutic goals and patient satisfaction (maintained in the long term and periodic goals reassessment recommended every 3-6 months). In the second round, half of the statements reached consensus, all related to patient follow-up, treatment goals, and atopic comorbidities. The statements that did not reach consensus were related to diagnosis (biomarkers, allergy, and food testing) and starting patients on conventional systemic treatment rather than advanced treatment. The study assessed expert opinion regarding a variety of topics related to the clinical approach to patients with moderate-to-severe atopic dermatitis, in order to provide guidance on the diagnosis and management of patients with atopic dermatitis.

Foxp3 and Bcl6 deficiency synergistically induces spontaneous development of atopic dermatitis-like skin disease

Atopic dermatitis (AD) is a common chronic skin disease caused by immune dysfunction, specifically the hyperactivation of Th2 immunity. AD is a complex disease with multiple factors contributing to its development; however, the interaction between these factors is not fully understood. In this study, we demonstrated that the conditional deletion of both the forkhead box p3 (Foxp3) and B-cell lymphoma 6 (Bcl6) genes induced the spontaneous development of AD-like skin inflammation with hyperactivation of type 2 immunity, skin barrier dysfunction, and pruritus, which were not induced by the single deletion of each gene. Furthermore, the development of AD-like skin inflammation was largely dependent on IL-4/13 signaling but not on immunoglobulin E (IgE). Interestingly, we found that the loss of Bcl6 alone increased the expression of thymic stromal lymphopoietin (TSLP) and interleukin (IL)-33 in the skin, suggesting that Bcl6 controls Th2 responses by suppressing TSLP and IL-33 expression in epithelial cells. Our results suggest that Foxp3 and Bcl6 cooperatively suppress the pathogenesis of AD. Furthermore, these results revealed an unexpected role of Bcl6 in suppressing Th2 responses in the skin.

Improvements in Gut Microbiome Composition Predict the Clinical Efficacy of a Novel Synbiotics Formula in Children with Mild to Moderate Atopic Dermatitis

Atopic dermatitis (AD) is a common chronic inflammatory skin disease with a significant association with various type-2 inflammation-related comorbidities. Ongoing research suggests the crucial involvement of gut microbiome, especially in childhood onset AD, and hence, probiotics have emerged as a potential non-steroid-based therapeutics option to complement existing AD management plans. In order to delineate the impact of probiotics in the gut microbiome of pediatric AD patients from southern China, targeted 16S rRNA sequencing and thorough bioinformatic analysis were performed to analyze the gut microbiome profiles of 24 AD children after taking an orally administered novel synbiotics formula with triple prebiotics for 8 weeks. A notable improvement in Eczema Area and Severity Index (EASI) (p = 0.008) was observed after taking an 8-week course of probiotics, with no adverse effects observed. The relative abundances of key microbial drivers including Bacteroides fragilis and Lactobacillus acidophilus were significantly increased at week 8. We also found that the positive responsiveness towards an 8-week course of probiotics was associated with improvements in the gut microbiome profile with a higher relative abundance of probiotic species. Over-represented functional abundance pathways related to vitamin B synthesis and peptidoglycan recycling may imply the underlying mechanism. In summary, our study suggests how the gut microbial landscape shifts upon probiotic supplementation in AD children, and provides preliminary evidence to support targeted probiotic supplementation for the management of childhood AD.

The prevalence of sensitization to food allergens in children with atopic dermatitis

INTRODUCTION

Atopic dermatitis (AD) has a complex pathophysiology. The course of the disease is affected by both environmental factors and allergen hypersensitivities. Food and aeroallergens have a significant role in the pathogenesis and disease control.

OBJECTIVE

In this study, it was aimed to determine the prevalence of food and aeroallergen sensitivity of children with AD.

METHODS

Children under 18 years with AD who applied to pediatric allergy and immunology outpatient clinics were evaluated. All patients had a skin prick test (SPT) within most common food and aeroallergens.

RESULTS

One hundred seventy three patients were studied. Most of the moderate and severe AD patients were boys (boys 64% vs. girls 47%). Symptoms started earlier and positive results in SPTs with food allergens were more common in patients with SCORAD (SCORing Atopic Dermatitis) >25 (p < 0.0001). Egg white (39%), egg yolk (31%), cow's milk (13%) and wheat flour (5%), were the most common allergens, respectively. The SCORAD scores were higher in multiple food sensitized patients' groups (p < 0.001). Although, food sensitizations were prevalent in patients who had higher SCORAD scores (p = 0.001), there was no significant difference in sensitization with aeroallergens. (p = 0.392).

CONCLUSION

Sensitizations to both food and aeroallergens are common in patients with AD. In addition, sensitization to these allergens and SCORAD severity in patients with AD have positive correlation.

On the definition of dermatological disease. Part 1: conceptual frameworks

Little attention is paid to disease definition in dermatology and how such definitions come about, yet defining a disease is a fundamental step upon which all subsequent clinical management and prognostic judgements depend. Developing diagnostic criteria is also a critically important step for research purposes so that studies referring to groups of people can be compared in a meaningful way. This short review introduces the concepts of regressive and progressive nosology, and how definitions of a dermatological disease can evolve in a useful way as knowledge about that disease increases. It also highlights the dangers of panchrestons - names that try to explain all yet end up explaining very little. It also considers approaches to disease definition, such as whether a binary yes/no or continuous approach is more appropriate. Conceptual frameworks including essentialistic vs. nominalistic approaches using the biomedical or biopsychosocial perspectives are articulated. The review then illustrates hazards of underdiagnosis and overdiagnosis, and introduces the notion of 'disease mongering' - the selling of disease in order to promote the use of medicines. The review concludes with a reaffirmation of the importance of defining dermatological disease, and why any new diagnostic criteria must be shown to increase predictive ability before they are assimilated into clinical practice and research.

Atopic Dermatitis and Food Allergy: A Complex Interplay What We Know and What We Would Like to Learn

Atopic dermatitis (AD) is a chronic inflammatory skin disorder characterized by intense pruritus, eczematous lesions, and relapsing course. It presents with great clinical heterogeneity, while underlying pathogenetic mechanisms involve a complex interplay between a dysfunctional skin barrier, immune dysregulation, microbiome dysbiosis, genetic and environmental factors. All these interactions are shaping the landscape of AD endotypes and phenotypes. In the “era of allergy epidemic”, the role of food allergy (FA) in the prevention and management of AD is a recently explored “era”. Increasing evidence supports that AD predisposes to FA and not vice versa, while food allergens are presumed as one of the triggers of AD exacerbations. AD management should focus on skin care combined with topical and/or systemic treatments; however, in the presence of suspected food allergy, a thorough allergy evaluation should be performed. Food-elimination diets in food-allergic cases may have a beneficial effect on AD morbidity; however, prolonged, unnecessary diets are highly discouraged since they can lead to loss of tolerance and potentially increase the risk of IgE-mediated food allergy. Preventive AD strategies with the use of topical emollients and anti-inflammatory agents as well as early introduction of food allergens in high-risk infants seem promising in managing and preventing food allergy in AD patients. The current review aims to overview data on the complex AD/FA relationship and provide the most recent developments on whether food allergy interventions change the AD course and vice versa.

Patterns of Atopic Eczema Disease Activity From Birth Through Midlife in 2 British Birth Cohorts

Importance

Atopic eczema is characterized by a heterogenous waxing and waning course, with variable age of onset and persistence of symptoms. Distinct patterns of disease activity such as early-onset/resolving and persistent disease have been identified throughout childhood; little is known about patterns into adulthood.

Objective

This study aimed to identify subtypes of atopic eczema based on patterns of disease activity through mid-adulthood, to examine whether early life risk factors and participant characteristics are associated with these subtypes, and to determine whether subtypes are associated with other atopic diseases and general health in mid-adulthood.

Design, Setting, and Participants

This study evaluated members of 2 population-based birth cohorts, the 1958 National Childhood Development Study (NCDS) and the 1970 British Cohort Study (BCS70). Participant data were collected over the period between 1958 and 2016. Data were analyzed over the period between 2018 and 2020.

Main Outcomes and Measures

Subtypes of atopic eczema were identified based on self-reported atopic eczema period prevalence at multiple occasions. These subtypes were the outcome in models of early life characteristics and an exposure variable in models of midlife health.

Results

Latent class analysis identified 4 subtypes of atopic eczema with distinct patterns of disease activity among 15 939 individuals from the NCDS (51.4% male, 75.4% White) and 14 966 individuals from the BCS70 (51.6% male, 78.8% White): rare/no (88% to 91%), decreasing (4%), increasing (2% to 6%), and persistently high (2% to 3%) probability of reporting prevalent atopic eczema with age. Sex at birth and early life factors, including social class, region of residence, tobacco smoke exposure, and breastfeeding, predicted differences between the 3 atopic eczema subtypes and the infrequent/no atopic eczema group, but only female sex differentiated the high and decreasing probability subtypes (odds ratio [OR], 1.99; 95% CI, 1.66-2.38). Individuals in the high subtype were most likely to experience asthma and rhinitis, and those in the increasing subtype were at higher risk of poor self-reported general (OR, 1.29; 95% CI, 1.09-1.53) and mental (OR 1.45; 95% CI, 1.23-1.72) health in midlife.

Conclusions and Relevance

The findings of this cohort study suggest that extending the window of observation beyond childhood may reveal clear subtypes of atopic eczema based on patterns of disease activity. A newly identified subtype with increasing probability of activity in adulthood warrants additional attention given observed associations with poor self-reported health in midlife.

Efficacy of moisturizers in paediatric atopic dermatitis: A systematic review and meta-analysis of randomised controlled trials

BACKGROUND

Topical moisturizer is recommended for atopic dermatitis.

AIMS

The aim of the study was to investigate the knowledge gap regarding the efficacy of moisturizer in young patients.

METHODS

A systematic review and meta-analysis were conducted on randomised controlled trials comparing participant's ≤15 years with atopic dermatitis, receiving either topical moisturizer or no moisturizer treatment. Certainty of evidence was assessed using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) framework.

RESULTS

Six trials were included (intervention n= 436; control n= 312). Moisturizer use extended time to flare by 13.52 days (95% confidence interval 0.05-26.99, I2 88%). Greater reduction in risk of relapse was observed during the first month of latency (pooled risk ratio 0.47, 95% confidence interval 0.31-0.72, I2 28%) compared to the second and third months (pooled risk ratio 0.65, 95% confidence interval 0.47-0.91, I2 35% and pooled risk ratio 0.63, 95% confidence interval 0.47-0.83, I2 33%, respectively).Treated patients were 2.68 times more likely to experience a three-six months remission (95% confidence interval1.18-6.09, I2 56%). Moisturizer minimally improved disease severity and quality of life.

LIMITATIONS

There is a dire need to conduct randomised controlled trialswith more robust and standardised designs.

CONCLUSION

Moisturizer benefits young patients with atopic dermatitis. However, more research is needed to better estimate its efficacy.

Four childhood atopic dermatitis subtypes identified from trajectory and severity of disease and internally validated in a large UK birth cohort

BACKGROUND

Atopic dermatitis (AD) disease activity and severity is highly variable during childhood. Early attempts to identify subtypes based on disease trajectory have assessed AD presence over time without incorporating severity.

OBJECTIVES

To identify childhood AD subtypes from symptom severity and trajectories, and determine associations with genetic risk factors, comorbidities and demographic and environmental variables.

METHODS

We split data from children in the Avon Longitudinal Study of Parents and Children birth cohort into development and validation sets. To identify subtypes, we ran latent class analyses in the development set on AD symptom reports up to age 14 years. We regressed identified subtypes on nongenetic variables in mutually adjusted, multiply imputed (genetic: unadjusted, complete case) multinomial regression analyses. We repeated analyses in the validation set and report confirmed results.

RESULTS

There were 11 866 children who contributed to analyses. We identified one Unaffected/Rare class (66% of children) and four AD subtypes: Severe-Frequent (4%), Moderate-Frequent (7%), Moderate-Declining (11%) and Mild-Intermittent (12%). Symptom patterns within the first two subtypes appeared more homogeneous than the last two. Filaggrin (FLG) null mutations, an AD polygenic risk score (PRS), being female, parental AD and comorbid asthma were associated with higher risk for some or all subtypes; FLG, AD-PRS and asthma associations were stronger along a subtype gradient arranged by increasing severity and frequency; FLG and AD-PRS further differentiated some phenotypes from each other.

CONCLUSIONS

Considering severity and AD trajectories leads to four well-defined and recognizable subtypes. The differential associations of risk factors among and between subtypes is novel and requires further research.

Surgical Wound Complications after Knee Cruciate Ligament Reconstruction in Patients with Atopic Dermatitis

Atopic dermatitis (AD), sometimes referred to as eczema, is a common skin disease, and skin barrier dysfunction and immunological disorders are well recognized. However, surgical wound complications after orthopaedic surgery in patients with AD have not been described. This study aimed to report four patients with AD who developed foreign body reactions to FiberWire sutures with or without surgical wound infection (SSI) after knee cruciate ligament reconstruction (CLR). The mean age was 19.8 (range, 16-25) years, and patients 1 and 3 underwent reconstructions of the posterior and anterior cruciate ligament, respectively. At a mean of 7.5 (range, 4-10) weeks postoperatively, discharge from the surgical wound at the tibial side of the fixed graft was identified. All patients were treated with continuous saline lavage and antibiotics; however, their wounds did not heal. Second-look arthroscopy and hardware removal were performed at a mean 12.2 (range, 9-15) months postoperatively. Proliferated granulation tissue surrounding the FiberWire was identified. Intraoperative wound cultures were negative in three of the four patients. Histological examination of the tissues adjacent to the FiberWire revealed a foreign body reaction. All wounds healed immediately after the second surgery. In addition to SSI, foreign body reactions are more likely to occur in patients with AD than in those without AD. Preoperative management of AD by dermatologists and consideration of appropriate suture materials are mandatory to reduce surgical wound complications after knee CLR in patients with AD.

Basophils promote barrier dysfunction and resolution in the atopic skin

BACKGROUND

The type 2 cytokines IL-4 and IL-13 promote not only atopic dermatitis (AD) but also the resolution of inflammation. How type 2 cytokines participate in the resolution of AD is poorly known.

OBJECTIVE

Our aim was to determine the mechanisms and cell types governing skin inflammation, barrier dysfunction, and resolution of inflammation in a model of AD.

METHODS

Mice that exhibit expression of IL-4, IL-13, and MCPT8 or that could be depleted of basophils or eosinophils, be deficient in IL-4 or MHC class II molecules, or have basophils lacking macrophage colony-stimulating factor (M-CSF) were treated with calcipotriol (MC903) as an acute model of AD. Kinetics of the disease; keratinocyte differentiation; and leukocyte accumulation, phenotype, function, and cytokine production were measured by transepidermal water loss, histopathology, molecular biology, or unbiased analysis of spectral flow cytometry.

RESULTS

In this model of AD, basophils were activated systemically and were the initial and main source of IL-4 in the skin. Basophils and IL-4 promoted epidermal hyperplasia and skin barrier dysfunction by acting on keratinocyte differentiation during inflammation. Basophils, IL-4, and basophil-derived M-CSF inhibited the accumulation of proinflammatory cells in the skin while promoting the expansion and function of proresolution M2-like macrophages and the expression of probarrier genes. Basophils kept their proresolution properties during AD resolution.

CONCLUSION

Basophils can display both beneficial and detrimental type 2 functions simultaneously during atopic inflammation.

Basophils add fuel to the flame of eczema itch

Children and adults with atopic dermatitis suffer from intractable chronic itch and can also experience acute itch flare ups that significantly increase itch intensity. In this issue of Cell, Wang et al. demonstrate that a subset of basophils activates sensory neurons to drive allergen-evoked itch flare ups in atopic dermatitis.

DNA Methylation Array Identifies Golli-MBP as a Biomarker for Disease Severity in Childhood Atopic Dermatitis

In this study, we investigated the changes in global methylation status and its functional relevance in childhood atopic dermatitis (AD). Differences in epigenome-scale methylation events in peripheral blood associated with childhood AD were screened using DNA methylation arrays of 24 patients with AD compared with 24 control subjects. Of the 16,840 differentially methylated CpG regions between AD and control subjects, >97% CpG loci revealed hypomethylation in patients with childhood AD. Among the globally hypomethylated loci, we identified two CpG clusters within the golli-mbp locus of the MBP gene, which was functionally enriched by subnetwork enrichment analysis as an orchestrator among associated genes. The differential hypomethylation of the top-ranked cg24700313 cluster in the golli-mbp locus was validated by pyrosequencing in an independent cohort of 224 children with AD and 44 control subjects. DNA methylation was found to be negatively correlated with disease severity but showed no significant correlation with IgE levels after age adjustment. The multivariate correlation analysis represents a higher score in AD intensity with significantly increased IgE levels and decreased methylation levels in cg27400313. We concluded that methylation loss in the golli-mbp locus is an epigenetic factor associated with disease severity of childhood AD.

Diagnosis and management of atopic dermatitis

ABSTRACT

Atopic dermatitis is a chronic inflammatory skin condition that affects patients of all ages. The disease is characterized by xerosis (dry skin) and intensely pruritic lesions distributed throughout the body. This article reviews diagnostic features and treatments for atopic dermatitis.

Microbial and transcriptional differences elucidate atopic dermatitis heterogeneity across skin sites

It is well established that different sites in healthy human skin are colonized by distinct microbial communities due to different physiological conditions. However, few studies have explored microbial heterogeneity between skin sites in diseased skin, such as atopic dermatitis (AD) lesions. To address this issue, we carried out deep analysis of the microbiome and transcriptome in the skin of a large cohort of AD patients and healthy volunteers, comparing two physiologically different sites: upper back and posterior thigh. Microbiome samples and biopsies were obtained from both lesional and nonlesional skin to identify changes related to the disease process. Transcriptome analysis revealed distinct disease-related gene expression profiles depending on anatomical location, with keratinization dominating the transcriptomic signatures in posterior thigh, and lipid metabolism in the upper back. Moreover, we show that relative abundance of Staphylococcus aureus is associated with disease severity in the posterior thigh, but not in the upper back. Our results suggest that AD may select for similar microbes in different anatomical locations-an "AD-like microbiome," but distinct microbial dynamics can still be observed when comparing posterior thigh to upper back. This study highlights the importance of considering the variability across skin sites when studying the development of skin inflammation.

Nomenclature and clinical phenotypes of atopic dermatitis

Atopic dermatitis is a heterogeneous disease and resists classification. In this review, we discuss atopic dermatitis nomenclature and identify morphologic phenotypes, which will facilitate correct diagnoses and development of treatment strategies. We support using the term 'atopic dermatitis' rather than eczema, because it describes the allergic background and inflammation ('itis') as drivers of the disease. Atopic dermatitis has many morphologic manifestations that vary by topographic area affected, age, or race and require consideration in differential diagnosis. Different phenotypes based on morphology and topographic location, ethnicity, and age are discussed. A better-defined phenotype identification for atopic dermatitis will facilitate earlier and correct diagnosis of this complex condition and inform selection of the most appropriate treatment choice in an era in which targeted therapies may generate more individualized patient care.

A basophil-neuronal axis promotes itch

Itch is an evolutionarily conserved sensation that facilitates expulsion of pathogens and noxious stimuli from the skin. However, in organ failure, cancer, and chronic inflammatory disorders such as atopic dermatitis (AD), itch becomes chronic, intractable, and debilitating. In addition to chronic itch, patients often experience intense acute itch exacerbations. Recent discoveries have unearthed the neuroimmune circuitry of itch, leading to the development of anti-itch treatments. However, mechanisms underlying acute itch exacerbations remain overlooked. Herein, we identify that a large proportion of patients with AD harbor allergen-specific immunoglobulin E (IgE) and exhibit a propensity for acute itch flares. In mice, while allergen-provoked acute itch is mediated by the mast cell-histamine axis in steady state, AD-associated inflammation renders this pathway dispensable. Instead, a previously unrecognized basophil-leukotriene (LT) axis emerges as critical for acute itch flares. By probing fundamental itch mechanisms, our study highlights a basophil-neuronal circuit that may underlie a variety of neuroimmune processes.

Atopic dermatitis epidemiology and unmet need in the United Kingdom

Atopic dermatitis (AD), also known as atopic eczema, is a chronic inflammatory skin condition associated with a significant health-related and socioeconomic burden, and is characterized by intense itch, disruption of the skin barrier, and upregulation of type 2-mediated immune responses. The United Kingdom (UK) has a high prevalence of AD, affecting 11-20% of children and 5-10% of adults. Approximately 2% of all cases of childhood AD in the UK are severe. Despite this, most AD treatments are performed at home, with little contact with healthcare providers or services. Here, we discuss the course of AD, treatment practices, and unmet need in the UK. Although the underlying etiology of the disease is still emerging, AD is currently attributed to skin barrier dysfunction and altered inflammatory responses. Management of AD focuses on avoiding triggers, improving skin hydration, managing exacerbating factors, and reducing inflammation through topical and systemic immunosuppressants. However, there is a significant unmet need to improve the overall management of AD and help patients gain control of their disease through safe and effective treatments. Approaches that target individual inflammatory pathways (e.g. dupilumab, anti-interleukin (IL)-4 receptor α) are emerging and likely to provide further therapeutic opportunities for patient benefit.

Free fatty acid receptor 4 (FFA4) activation ameliorates 2,4-dinitrochlorobenzene-induced atopic dermatitis by increasing regulatory T cells in mice

High dose intake of docosahexaenoic acid showed beneficial effects on atopic dermatitis in patients and was found to increase regulatory T cells in mice, but its molecular target has not been identified. Free fatty acid receptor 4 (FFA4, also known as GPR120) is a receptor sensing polyunsaturated long-chain fatty acids including docosahexaenoic acid. In the present study, we examined whether FFA4 acted as a therapeutic target of docosahexaenoic acid for treating atopic dermatitis. Experimental atopic dermatitis was induced in mice by 2,4-dinitrochlorobenzene (DNCB) sensitization on day 0, followed by repeated DNCB challenges from D7 to D48. The mice were treated with a selective agonist compound A (30 mg· kg⁻¹· d⁻¹, ip) from D19 to D48, and sacrificed on D49. We found that DNCB-induced atopic dermatitis-like skin lesions, i.e. hypertrophy and mast cell infiltration in skin tissues, as well as markedly elevated serum IgE levels. Administration of compound A significantly suppressed the atopic responses in ears and lymph nodes, such as hypertrophy and mast cell infiltration in the ears, enlarged sizes of lymph nodes, and elevated serum IgE and levels of cytokines IL-4, IL-13, IL-17, and IFN-γ in ear tissue. The therapeutic effects of compound A were abolished by FFA4 knockout. Similarly, increased CD4⁺Foxp3⁺ regulatory T-cell population in lymph nodes was observed in wide-type mice treated with compound A, but not seen in FFA4-deficient mice. In conclusion, we demonstrate that activation of FFA4 ameliorates atopic dermatitis by increasing CD4⁺Foxp3⁺ regulatory T cells, suggesting FFA4 as a therapeutic target for atopic dermatitis.

Genetic and Epigenetic Aspects of Atopic Dermatitis

Atopic dermatitis is a heterogeneous disease, in which the pathogenesis is associated with mutations in genes encoding epidermal structural proteins, barrier enzymes, and their inhibitors; the role of genes regulating innate and adaptive immune responses and environmental factors inducing the disease is also noted. Recent studies point to the key role of epigenetic changes in the development of the disease. Epigenetic modifications are mainly mediated by DNA methylation, histone acetylation, and the action of specific non-coding RNAs. It has been documented that the profile of epigenetic changes in patients with atopic dermatitis (AD) differs from that observed in healthy people. This applies to the genes affecting the regulation of immune response and inflammatory processes, e.g., both affecting Th1 bias and promoting Th2 responses and the genes of innate immunity, as well as those encoding the structural proteins of the epidermis. Understanding of the epigenetic alterations is therefore pivotal to both create new molecular classifications of atopic dermatitis and to enable the development of personalized treatment strategies.

What is the evidence for interactions between filaggrin null mutations and environmental exposures in the aetiology of atopic dermatitis? A systematic review

BACKGROUND

Epidemiological studies indicate that gene-environment interactions play a role in atopic dermatitis (AD).

OBJECTIVES

To review the evidence for gene-environment interactions in AD aetiology, focusing on filaggrin (FLG) loss-of-function mutations.

METHODS

A systematic search from inception to September 2018 in Embase, MEDLINE and BIOSIS was performed. Search terms included all synonyms for AD and filaggrin/FLG; any genetic or epidemiological study design using any statistical methods were included. Quality assessment using criteria modified from guidance (ROBINS-I and Human Genome Epidemiology Network) for nonrandomized and genetic studies was completed, including consideration of power. Heterogeneity of study design and analyses precluded the use of meta-analysis.

RESULTS

Of 1817 papers identified, 12 studies fulfilled the inclusion criteria required and performed formal interaction testing. There was some evidence for FLG-environment interactions in six of the studies (P-value for interaction ≤ 0·05), including early-life cat ownership, older siblings, water hardness, phthalate exposure, higher urinary phthalate metabolite levels (which all increased AD risk additional to FLG null genotype) and prolonged breastfeeding (which decreased AD risk in the context of FLG null genotype). Major limitations of published studies were the low numbers of individuals (ranging from five to 94) with AD and FLG loss-of-function mutations and exposure to specific environmental factors, and variation in exposure definitions.

CONCLUSIONS

Evidence on FLG-environment interactions in AD aetiology is limited. However, many of the studies lacked large enough sample sizes to assess these interactions fully. Further research is needed with larger sample sizes and clearly defined exposure assessment. Linked Comment: Park and Seo. Br J Dermatol 2020; 183:411.

Atopic dermatitis

Atopic dermatitis is a common inflammatory skin disorder characterised by recurrent eczematous lesions and intense itch. The disorder affects people of all ages and ethnicities, has a substantial psychosocial impact on patients and relatives, and is the leading cause of the global burden from skin disease. Atopic dermatitis is associated with increased risk of multiple comorbidities, including food allergy, asthma, allergic rhinitis, and mental health disorders. The pathophysiology is complex and involves a strong genetic predisposition, epidermal dysfunction, and T-cell driven inflammation. Although type-2 mechanisms are dominant, there is increasing evidence that the disorder involves multiple immune pathways. Currently, there is no cure, but increasing numbers of innovative and targeted therapies hold promise for achieving disease control, including in patients with recalcitrant disease. We summarise and discuss advances in our understanding of the disease and their implications for prevention, management, and future research.

What makes an inflammatory disease inflammatory? An overview of inflammatory mechanisms of allergic contact dermatitis, atopic dermatitis and psoriasis

Inflammatory response in the skin is important for host defense against a broad spectrum of insults including microorganisms, chemicals, radiation and physical trauma. When the inflammatory process becomes prolonged and self-perpetuating, illness occurs. In this review, we discuss recent findings regarding the complex inflammatory mechanisms in allergic contact dermatitis, atopic dermatitis and psoriasis.

Genetics and Epigenetics of Atopic Dermatitis: An Updated Systematic Review

BACKGROUND

Atopic dermatitis is a common inflammatory skin disorder that affects up to 15-20% of the population and is characterized by recurrent eczematous lesions with intense itching. As a heterogeneous disease, multiple factors have been suggested to explain the nature of atopic dermatitis (AD), and its high prevalence makes it necessary to periodically compile and update the new information available. In this systematic review, the focus is set at the genetic and epigenetic studies carried out in the last years.

METHODS

A systematic literature review was conducted in three scientific publication databases (PubMed, Cochrane Library, and Scopus). The search was restricted to publications indexed from July 2016 to December 2019, and keywords related to atopic dermatitis genetics and epigenetics were used.

RESULTS

A total of 73 original papers met the inclusion criteria established, including 9 epigenetic studies. A total of 62 genes and 5 intergenic regions were described as associated with AD.

CONCLUSION

Filaggrin (FLG) polymorphisms are confirmed as key genetic determinants for AD development, but also epigenetic regulation and other genes with functions mainly related to the immune system and extracellular matrix, reinforcing the notion of skin homeostasis breakage in AD.

β-1,3-glucanase rOle e 9 and MnSOD rAsp f 6 IgE reactivity are the signature of atopic dermatitis in the Mediterranean area

BACKGROUND

Atopic dermatitis (AD) represents a chronic skin disorder seriously affecting patients' QoL and is often associated with immunological imbalance, disorders of the skin barrier function and environmental factors.

OBJECTIVE

We extensively studied the proteomic IgE sensitization profile in a large AD Mediterranean cohort.

METHODS

A total of 588 individuals with moderate-severe (70.6%) or mild and/or history of (29.4%) AD were evaluated in comparison to 1285 unselected atopic controls (AC) with a history of adverse reactions to foods, allergic rhinitis and/or bronchial asthma by means of ImmunoCAP ISAC₁₁₂ ® and Allergy Explorer-ALEX® microarray analysis.

RESULTS

The olive tree pollen β-1,3-glucanase rOle e 9 and the manganese superoxide dismutase from Aspergillus rAsp f 6 were the molecules most significantly associated with AD occurrence and allowed to discriminate among the moderate and severe forms of disease. An IgE hyper-reactivity to cypress, grasses, olive tree, house dust mites (including rDer p 11), and to all cross-reactive components except profilin and polcalcin was observed. About 60% of adults with severe AD were sensitized to nsLTPs. Cross-reactive carbohydrate determinants (CCDs) IgE was found in about one-third of AD participants. Hen eggs nGal d 1 IgE sensitization was more prevalent in the paediatric population, whilst rAsp f 6 and rOle e 9 reactivity was found particularly in older patients. Despite the status of widespread IgE sensitization to both environmental and food allergens, a reduced frequency of patient-reported severe reactions to food or of asthma was observed in AD patients compared to AC, particularly in case of concomitant Ole e 9 reactivity.

CONCLUSION AND CLINICAL RELEVANCE

Testing IgE reactivity to a large panel of molecular components unveils important associations between IgE reactivity profiles and AD clinical presentation, highlights the allergens useful for a precise AD signature and allows the detection of interesting sensitisations patterns.

How does parental history of atopic disease predict the risk of atopic dermatitis in a child? A systematic review and meta-analysis

BACKGROUND

Parental history of atopic disease is a well-established risk factor for the development of atopic dermatitis (AD), but several aspects of this association remain unclear.

OBJECTIVE

We sought to determine the association of parental history of atopic disease with AD in offspring.

METHODS

We searched PubMed and EMBASE through June 2018 for relevant records and adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Pooled odds ratios (ORs) with 95% CI were calculated using random-effects models.

RESULTS

A total of 163 records covering 149 unique studies were included. Of these, 119 studies were included in the meta-analysis. Individuals with parental history of atopic disease had increased odds of AD (OR, 1.81; 95% CI, 1.65-1.99). Parental asthma (OR, 1.56; 95% CI, 1.18-2.05) and allergic rhinitis (OR, 1.68; 95% CI, 1.34-2.11) had a smaller effect than AD (OR, 3.30; 95% CI, 2.46-4.42). The effect of maternal and paternal history was comparable for all atopic diseases. An increase in odds was observed when comparing the effect of having 1 (OR, 1.30; 95% CI, 1.15-1.47) or 2 atopic parents (OR, 2.08; 95% CI, 1.83-2.36), as well as having a parent with 1 (OR, 1.49; 95% CI, 1.28-1.74) or more atopic diseases (OR, 2.32; 95% CI, 1.92-2.81).

CONCLUSIONS

This study provides evidence-based risk estimates that may guide physicians who counsel parents with a history of atopic disease about their children's risk of AD. This information is of particular importance for future efforts toward establishing prophylactic interventions for AD on a general population level.

The Microbiome and Atopic Dermatitis: A Review

The microbiome is defined as the sum of microbes, their genomes, and interactions in a given ecological niche. Atopic dermatitis is a multifactorial chronic inflammatory skin disease leading to dryness and itchiness of the skin. It is often associated with comorbidities such as allergic rhinoconjunctivitis and asthma. Today, culture-free techniques have been established to define microbes and their genomes that may be both detrimental and beneficial for their host. There are signs that microbes, both on skin and in the gut, may influence the course of atopic dermatitis. Antiseptic treatment has been used for decades, however now, with the help of traditional culture-based methods and modern metagenomics, we are beginning to understand that targeted treatment of dysbiosis may possibly become part of an integrated therapy plan in the future.

Atopic dermatitis without serum immunoglobulin E elevation or loss-of-function filaggrin gene mutation in a patient with X-linked agammaglobulinemia

A case of atopic dermatitis (AD) with X-linked agammaglobulinemia (XLA), which is one of the primary immunodeficiency diseases, is reported. A 12-year-old boy had suffered from dry skin and recurrent itchy eruptions since he was 2 years old, and he was diagnosed as having XLA at the age of 4 years. His total immunoglobulin (Ig)E level was 7 IU/mL, even with regular Ig replacement therapy. Furthermore, filaggrin (FLG) mutations known in the Japanese population were not found. His skin lesions were well controlled by the application of a mild-class topical steroid and a moisturizer, though he developed folliculitis due to Staphylococcus aureus infection during treatment with a strong-class topical steroid. This case suggests that the FLG mutation and IgE-mediated sensitization are not necessary to induce AD skin manifestation.

Atopic March: Collegium Internationale Allergologicum Update 2020

In recent decades, the worldwide prevalence of allergic disease has increased considerably. The atopic march is a model aimed at explaining the apparent progression of allergic diseases from atopic dermatitis (AD) to allergic asthma (AA) and to allergic rhinitis (AR). It hypothesizes that allergic disease begins, typically in children, with the development of AD, then AA, and finally progresses to AR. This theory has been widely studied in cross-sectional and long-term longitudinal studies and it has been found that as prevalence of AD declines, prevalence of AA increases. A similar relationship is reported between AA and AR. The legitimacy of the atopic march model is, however, currently debated. Epidemiological evidence and criticism of longitudinal studies point to an overstatement of the atopic march's prevalence and incorrect mechanisms, opening a discussion for alternative models to better explain the pathophysiological and epidemiological processes that promote this progression of allergic diseases. Albeit, risk factors for the development and progression of allergic disease, particularly AD, are critical in identifying disease progression. Investigating the role of age, severity, family history, phenotype, and genetic traits may give a better indication into the progression of allergic diseases. In addition, studies following patients from infancy into adulthood and a general increase in longitudinal studies would help broaden the knowledge of allergic disease progression and the atopic march.

MicroRNAs: Potential Biomarkers and Targets of Therapy in Allergic Diseases?

MicroRNAs (miRNAs) are small non-coding RNA molecules that are 18-22 nucleotides long and highly conserved throughout evolution. Currently, they are considered one of the fundamental regulatory mechanisms of genes expression. It has been demonstrated that miRNAs are involved in many biologic processes, such as signal transduction, cell proliferation and differentiation, apoptosis and stress responses. More recently, the role of miRNA has also been revealed in numerous immunological and inflammatory disorders, including allergic inflammation. Specific miRNA profiles were demonstrated in asthma, allergic rhinitis and atopic dermatitis. A core set of miRNAs involved in atopic diseases include upregulated miR-21, miR-223, miR-146a, miR-142-5p, miR-142-3p, miR-146b, miR-155 and downregulated let-7 family, miR-193b and miR-375. Most of the involved miRNAs increase secretion of Th2 cytokines (miR-1248, miR-146b), decrease secretion of Th1 cytokines (miR-513-5p, miR-625-5p) or promote differentiation of T cells towards Th2 (miR-21, miR-19a). In asthma miR-140-3p, miR-708 and miR-142-3p play a role in hyperplasia and hypertrophy of bronchial smooth muscle cells. Some single miRNAs or, more probably, their sets hold the promise for their use as biomarkers of atopic diseases. They are also promising target of future therapies.

Altered hypothalamus-pituitary-adrenal axis function: A relevant factor in the comorbidity of atopic eczema and attention deficit/hyperactivity disorder?

Epidemiological data show a significant association between childhood atopic eczema (AE) and an increased risk to develop attention deficit/hyperactivity disorder (ADHD). However, the underlying mechanisms of the comorbidity of AE and ADHD are mostly unknown. We investigated whether alterations of hypothalamus-pituitary-adrenal (HPA) axis function represent a shared feature of AE and ADHD potentiating AE-ADHD comorbidity. Children aged 6-12 years with AE, ADHD, or comorbid AE + ADHD and healthy control (HC) children were examined cross-sectionally (N = 145). To evaluate HPA axis function, salivary cortisol in response to psychosocial stress (Trier Social Stress Test for Children, TSST-C), after awakening (cortisol awakening response, CAR), and throughout the day (short diurnal profile) and hair cortisol capturing long-term HPA axis activity were assessed. Quantile regression analyses showed an attenuated cortisol response (% maximum change) to the TSST-C in children with ADHD compared to HC. A diminished cortisol response to acute stress was also observed in the comorbid AE + ADHD group, in which the reduction was numerically even more pronounced. Contrary to our previous findings, no alteration of the cortisol response to the TSST-C was observed in children with AE. However, in children with AE, increased ADHD-like behavior (i.e., inattention, impulsivity, and overall ADHD symptom severity) was associated with a reduced HPA axis response to acute stress. No such associations were observed in children without AE. Groups did not differ in CAR, short diurnal profile, and hair cortisol. These findings underscore the potential relevance of HPA axis function in the pathophysiology of AE and ADHD with emphasis on stress reactivity. Additional studies are required to further explore the separate and joint role of the HPA axis in the pathophysiology of AE and ADHD.

Clinical onset of atopic eczema: Results from 2 nationally representative British birth cohorts followed through midlife

Background

Atopic eczema onset is described primarily in early childhood, and the frequency and characteristics of adult-onset disease remain controversial.

Objective

We sought to determine the proportion of subjects who report atopic eczema symptoms between birth and midadulthood and to examine demographic, immunologic, and genetic factors associated with period of symptom onset.

Methods

We conducted a longitudinal study using data from 2 nationally representative community-based birth cohorts from the United Kingdom: the British Cohort Studies 1958 and 1970. Subjects were followed from birth through age 42 to 50 years. The primary outcome was the age period of self-reported atopic eczema symptom onset based on repeated measures of self-reported atopic eczema at each survey wave.

Results

The annual period prevalence of atopic eczema ranged from 5% to 15% in 2 cohorts of more than 17,000 participants each followed from birth through middle age. There was no clear trend in prevalence by age, and among adults reporting active atopic eczema during a given year, only 38% had symptom onset reported in childhood. When compared with subjects whose eczema started in childhood, those with adult-onset disease were more likely to be women, from Scotland or Northern England, of lower childhood socioeconomic group, smokers in adulthood, and less likely to have a history of asthma. In a subanalysis using data from the 1958 cohort only, genetic mutations previously associated with atopic eczema, including filaggrin-null mutations, and allergen-specific IgE were more common among those with childhood-onset disease.

Conclusion

Rates of self-reported atopic eczema remain high after childhood, and adult-onset atopic eczema has different risk factor associations than childhood-onset eczema.

Atopic dermatitis and autoimmunity: the occurrence of autoantibodies and their association with disease severity

Atopic dermatitis (AD) is a widespread condition that appears to be increasing in prevalence and severity worldwide, yet the underlying mechanisms are not well understood. Recent research has identified various similarities between AD and autoimmune conditions, as well as indicating that there may be an association between AD and autoimmunity. This systematic review evaluates the association between AD and autoimmunity, as well as between severity of disease in AD and autoimmunity, with an emphasis on the associations with autoantibodies. MEDLINE (1946 to December 2017) and Embase (1974 to December 2017) databases were searched. Further relevant articles were retrieved from reference lists. Only studies measuring direct indicators of autoimmunity, in humans, were included. Qualitative analysis was carried out for all studies. In addition, quantitative analysis was used to evaluate prevalence of IgE autoantibodies and anti-nuclear antibodies (ANAs) in AD patients and control subjects. The Mantel-Haenszel method was used with a random-effects model. 28 studies assessed the occurrence of autoantibodies in AD patients and 16 studies were used to evaluate association between disease severity and autoantibodies. Pooled analysis from 14 studies, involving 986 AD patients and 441 control subjects, showed that IgE autoantibodies were significantly more prevalent in patients with AD (P < 0.00001) than control subjects. Similar analysis was carried out for ANAs, with eight studies that involved 1045 AD patients and 1273 control subjects. ANAs were significantly more prevalent in patients with AD (P = 0.003). This quantitative analysis supported an association between AD and IgE autoantibodies, as well as between AD and ANAs. There was insufficient data to make similar conclusions for other indicators of autoimmunity. The weight of evidence also suggests an association between IgE autoantibodies and disease severity. There was insufficient evidence to make this link for other indicators of autoimmunity.

Probiotics for treating eczema

BACKGROUND

Eczema is a common chronic skin condition. Probiotics have been proposed as an effective treatment for eczema; their use is increasing, as numerous clinical trials are under way. This is an update of a Cochrane Review first published in 2008, which suggested that probiotics may not be an effective treatment for eczema but identified areas in which evidence was lacking.

OBJECTIVES

To assess the effects of probiotics for treating patients of all ages with eczema.

SEARCH METHODS

We updated our searches of the following databases to January 2017: the Cochrane Skin Group Specialised Register, the Cochrane Central Register of Controlled Trials (CENTRAL), in the Cochrane Library, the Global Resource of Eczema Trials (GREAT) database, MEDLINE, Embase, PsycINFO, the Allied and Complementary Medicine Database (AMED), and Latin American Caribbean Health Sciences Literature (LILACS). We searched five trials registers and checked the reference lists of included studies and relevant reviews for further references to relevant randomised controlled trials (RCTs). We also handsearched a number of conference proceedings. We updated the searches of the main databases in January 2018 and of trials registries in March 2018, but we have not yet incorporated these results into the review.

SELECTION CRITERIA

Randomised controlled trials of probiotics (live orally ingested micro-organisms) compared with no treatment, placebo, or other active intervention with no probiotics for the treatment of eczema diagnosed by a doctor.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures as expected by Cochrane. We recorded adverse events from the included studies and from a separate adverse events search conducted for the first review. We formally assessed reporting bias by preparing funnel plots, and we performed trial sequential analysis for the first primary outcome - eczema symptoms at the end of active treatment.We used GRADE to assess the quality of the evidence for each outcome (in italic font).

MAIN RESULTS

We included 39 randomised controlled trials involving 2599 randomised participants. We included participants of either gender, aged from the first year of life through to 55 years (only six studies assessed adults), who had mild to severe eczema. Trials were undertaken in primary and secondary healthcare settings, mainly in Europe or Asia. Duration of treatment ranged from four weeks to six months, and duration of follow-up after end of treatment ranged from zero to 36 months. We selected no standard dose: researchers used a variety of doses and concentrations of probiotics. The probiotics used were bacteria of the Lactobacillus and Bifidobacteria species, which were taken alone or combined with other probiotics, and were given with or without prebiotics. Comparators were no treatment, placebo, and other treatments with no probiotics.For all results described in this abstract, the comparator was no probiotics. Active treatment ranged from six weeks to three months for all of the following results, apart from the investigator-rated eczema severity outcome, for which the upper limit of active treatment was 16 weeks. With regard to score, the higher the score, the more severe were the symptoms. All key results reported in this abstract were measured at the end of active treatment, except for adverse events, which were measured during the active treatment period.Probiotics probably make little or no difference in participant- or parent-rated symptoms of eczema (13 trials; 754 participants): symptom severity on a scale from 0 to 20 was 0.44 points lower after probiotic treatment (95% confidence interval (CI) -1.22 to 0.33; moderate-quality evidence). Trial sequential analysis shows that target sample sizes of 258 and 456, which are necessary to demonstrate a minimum mean difference of -2 and -1.5, respectively, with 90% power, have been exceeded, suggesting that further trials with similar probiotic strains for this outcome at the end of active treatment may be futile.We found no evidence suggesting that probiotics make a difference in QoL for patients with eczema (six studies; 552 participants; standardised mean difference (SMD) 0.03, 95% CI -0.36 to 0.42; low-quality evidence) when measured by the participant or the parent using validated disease-specific QoL instruments.Probiotics may slightly reduce investigator-rated eczema severity scores (24 trials; 1596 participants). On a scale of 0 to 103 for total Severity Scoring of Atopic Dermatitis (SCORAD), a score combining investigator-rated eczema severity score and participant scoring for eczema symptoms of itch and sleep loss was 3.91 points lower after probiotic treatment than after no probiotic treatment (95% CI -5.86 to -1.96; low-quality evidence). The minimum clinically important difference for SCORAD has been estimated to be 8.7 points.We noted significant to extreme levels of unexplainable heterogeneity between the results of individual studies. We judged most studies to be at unclear risk of bias; six studies had high attrition bias, and nine were at low risk of bias overall.We found no evidence to show that probiotics make a difference in the risk of adverse events during active treatment (risk ratio (RR) 1.54, 95% CI 0.90 to 2.63; seven trials; 402 participants; low-quality evidence). Studies in our review that reported adverse effects described gastrointestinal symptoms.

AUTHORS' CONCLUSIONS

Evidence suggests that, compared with no probiotic, currently available probiotic strains probably make little or no difference in improving patient-rated eczema symptoms. Probiotics may make little or no difference in QoL for people with eczema nor in investigator-rated eczema severity score (combined with participant scoring for eczema symptoms of itch and sleep loss); for the latter, the observed effect was small and of uncertain clinical significance. Therefore, use of probiotics for the treatment of eczema is currently not evidence-based. This update found no evidence of increased adverse effects with probiotic use during studies, but a separate adverse events search from the first review revealed that probiotic treatment carries a small risk of adverse events.Results show significant, unexplainable heterogeneity between individual trial results. Only a small number of studies measured some outcomes.Future studies should better measure QoL scores and adverse events, and should report on new probiotics. Researchers should also consider studying subgroups of patients (e.g. patients with atopy or food allergies, adults) and standardising doses/concentrations of probiotics given.

Diagnosing atopic dermatitis in infancy: Questionnaire reports vs criteria-based assessment

BACKGROUND

Persisting atopic dermatitis (AD) is known to be associated with more serious allergic diseases at later ages; however, making an accurate diagnosis during infancy is challenging. We assessed the diagnostic performance of questionnaire-based AD measures with criteria-based in-person clinical assessments at age 1 year and evaluated the ability of these diagnostic methods to predict asthma, allergic rhinitis and food allergies at age 5 years.

METHODS

Data relate to 3014 children participating in the Canadian Healthy Infant Longitudinal Development (CHILD) Study who were directly observed in a clinical assessment by an experienced healthcare professional using the UK Working Party criteria. The majority (2221; 73.7%) of these children also provided multiple other methods of AD ascertainment: a parent reporting a characteristic rash on a questionnaire, a parent reporting the diagnosis provided by an external physician and a combination of these two reports.

RESULTS

Relative to the direct clinical assessment, the area under the Receiver Operating Characteristic curve for a parental report of a characteristic rash, reported physician diagnosis and a combination of both were, respectively, 0.60, 0.69 and 0.70. The strongest predictor of asthma at 5 years was AD determined by criteria-based in-person clinical assessment followed by the combination of parental and physician report.

CONCLUSIONS

These findings suggest that questionnaire data cannot accurately substitute for assessment by experienced healthcare professionals using validated criteria for diagnosis of atopic dermatitis. Combining the parental report with diagnosis by a family physician might sometimes be appropriate (eg to avoid costs of a clinical assessment).

Classifying atopic dermatitis: protocol for a systematic review of subtypes (phenotypes) and associated characteristics

INTRODUCTION

Atopic dermatitis is a complex disease with differing clinical presentations. Many attempts have been made to identify uniform subtypes, or phenotypes, of atopic dermatitis in order to identify different aetiologies, improve diagnosis, estimate more accurate clinical prognoses, inform treatment andmanagement or predict treatment efficacy andeffectiveness. However, no consensus yet exists on exactly what defines these phenotypes or how many there are and whether they are genuine or statistical artefacts. This review aims to identify previously reported phenotypes of atopic dermatitis, the features used to define them and any characteristics or clinical outcomes significantly associated with them.

METHODS AND ANALYSIS

We will search Ovid Embase, Ovid MEDLINE and Web of Science from inception to the latest available date at the time of the search for studies attempting to classify atopic dermatitis in humans using any cross-sectional or longitudinal epidemiological or interventional design. Primary outcomes are atopic dermatitis phenotypes, features used to define them and characteristics associated with them in subsequent analyses. A secondary outcome is the methodological approach used to derive them. Two reviewers will independently screen titles and abstracts for inclusion, extract data and assess study quality. We will present the results of this review descriptively and with frequencies where possible.

ETHICS AND DISSEMINATION

Ethical approval is not required for this study as it is a systematic review. We will report results from this systematic review in a peer-reviewed journal. The main value of this study will be to inform further research.

PROSPERO REGISTRATION NUMBER

CRD42018087500.

Atopic dermatitis

Atopic dermatitis (AD) is the most common chronic inflammatory skin disease, with a lifetime prevalence of up to 20% and substantial effects on quality of life. AD is characterized by intense itch, recurrent eczematous lesions and a fluctuating course. AD has a strong heritability component and is closely related to and commonly co-occurs with other atopic diseases (such as asthma and allergic rhinitis). Several pathophysiological mechanisms contribute to AD aetiology and clinical manifestations. Impairment of epidermal barrier function, for example, owing to deficiency in the structural protein filaggrin, can promote inflammation and T cell infiltration. The immune response in AD is skewed towards T helper 2 cell-mediated pathways and can in turn favour epidermal barrier disruption. Other contributing factors to AD onset include dysbiosis of the skin microbiota (in particular overgrowth of Staphylococcus aureus), systemic immune responses (including immunoglobulin E (IgE)-mediated sensitization) and neuroinflammation, which is involved in itch. Current treatments for AD include topical moisturizers and anti-inflammatory agents (such as corticosteroids, calcineurin inhibitors and cAMP-specific 3',5'-cyclic phosphodiesterase 4 (PDE4) inhibitors), phototherapy and systemic immunosuppressants. Translational research has fostered the development of targeted small molecules and biologic therapies, especially for moderate-to-severe disease.

Presence of atopy increases the risk of asthma relapse

OBJECTIVES

To describe the point prevalence of respiratory viruses/atypical bacteria using PCR and evaluate the impact of respiratory viruses/atypical bacteria and atopy on acute severity and clinical recovery in children with hospitalised and non-hospitalised asthma exacerbations.

DESIGN

This was a prospective study performed during 2009-2011.

SETTING

The study was performed in the emergency departments of two hospitals.

PATIENTS

244 children aged 2-16 years presenting with acute asthma to the emergency departments were recruited. A nasopharyngeal aspirate and allergen skin prick test were performed.

MAIN OUTCOME MEASURES

The outcomes were divided into (1) acute severity outcomes (Australian National Asthma Council assessment, hospitalisation, Functional Severity Scale, Acute Asthma Score, asthma quality of life questionnaires for parents (PACQLQ) on presentation, asthma diary scores (ADS) on presentation and length of hospitalisation) and (2) recovery outcomes (PACQLQ for 21 days, ADS for 14 days and representation for asthma for 21 days).

RESULTS

PCR for viruses/atypical bacteria was positive in 81.7% of children (75.1% human rhinovirus, codetection in 14.2%). Mycoplasma pneumoniae and Chlamydophila pneumoniae were rarely detected. The presence of micro-organisms had little impact on acute asthma or recovery outcomes. Children with atopy were significantly more likely to relapse and represent for medical care by day 14 (OR 1.11, 95% CI 1.00 to 1.23).

CONCLUSIONS

The presence of any viruses is associated with asthma exacerbations but does not appear to influence asthma recovery. In contrast, atopy is associated with asthma relapse. M. pneumoniae and C. pneumoniae are rare triggers of acute asthma in young children.

Risk factors for asthma occurrence in children with early-onset atopic dermatitis: An 8-year follow-up study

BACKGROUND

Children with early-onset atopic dermatitis (AD) are at substantial risk of developing asthma later in life, and identifying the critical window of detrimental exposure is advantageous for implementing preventive actions. The aim of this study was to evaluate the role of exposure to environmental modifiers during pregnancy and early childhood in asthma occurrence in an infantile AD cohort.

METHODS

Eligible study participants were selected from the Taiwan Birth Cohort Study, which enrolled 24 200 newborns in 2005. We enrolled those cases who had been diagnosed as having AD before 3 years of age and followed them up till age 8. We excluded those ever diagnosed with asthma before AD onset. The dependent variable was defined in terms of whether the participant was diagnosed as having asthma before 8 years of age. We applied logistic regression models to evaluate the risks of exposure to different determinants in asthma occurrence.

RESULTS

A total of 1549 children with AD had completed the 8-year follow-up, and 334 (21.6%) of them had asthma. The results revealed that male sex, lower birth order, maternal asthma history, maternal obesity before pregnancy, and environmental tobacco smoke exposure before 3 years of age were significant risk factors for further development of asthma. Furthermore, food allergy during early life, lower respiratory tract infection, and longer durations of symptomatic AD influenced asthma development later in life.

CONCLUSIONS

The findings confirmed the critical determinants for asthma occurrence in infantile AD, which may enable a more personalized approach to the prevention of asthma.

Identification of atopic dermatitis subgroups in children from 2 longitudinal birth cohorts

BACKGROUND

Atopic dermatitis (AD) is a prevalent disease with variable natural history. Longitudinal birth cohort studies provide an opportunity to define subgroups on the basis of disease trajectories, which may represent different genetic and environmental pathomechanisms.

OBJECTIVES

We sought to investigate the existence of distinct longitudinal phenotypes of AD and test whether these findings are reproducible in 2 independent cohorts.

METHODS

The presence of AD was examined in 2 birth cohort studies including 9894 children from the United Kingdom (ALSPAC) and 3652 from the Netherlands (PIAMA). AD was defined by parental report of a typical itchy and/or flexural rash. Longitudinal latent class analysis was used to investigate patterns of AD from birth to the age of 11 to 16 years. We investigated associations with known AD risk factors, including FLG null mutations, 23 other established AD-genetic risk variants, and atopic comorbidity.

RESULTS

Six latent classes were identified, representing subphenotypes of AD, with remarkable consistency between the 2 cohorts. The most prevalent class was early-onset-early-resolving AD, which was associated with male sex. Two classes of persistent disease were identified (early-onset-persistent and early-onset-late-resolving); these were most strongly associated with the AD-genetic risk score as well as personal and parental history of atopic disease. A yet unrecognized class of mid-onset-resolving AD, not associated with FLG mutations, but strongly associated with asthma, was identified.

CONCLUSIONS

Six classes based on temporal trajectories of rash were consistently identified in 2 population-based cohorts. The differing risk factor profiles and diverse prognoses demonstrate the potential importance of a stratified medicine approach for AD.

Prenatal Exposure to Phthalates and the Development of Eczema Phenotypes in Male Children: Results from the EDEN Mother-Child Cohort Study

BACKGROUND

Contradictory results exist regarding the importance of early-life exposure to phthalates for development of childhood eczema.

OBJECTIVES

We evaluated the association between maternal urinary concentrations of phthalate metabolites between the 24th and 28th week of gestation and occurrence of eczema in their sons up to 5 y of age, according to allergic sensitization as assessed by total immunoglobulin E (IgE) in a subsample of individuals.

METHODS

Data on health outcomes and background factors were collected using five standardized annual questionnaires completed by parents at the children's ages of 1-5 y, and their associations with phthalate metabolite urinary concentrations were assessed in 604 mother-son pairs with adjusted multiple logistic regression and Cox's survival model. Several eczema phenotypes were considered. Atopic status was assessed at 5 y of age in 293 boys through total IgE assessment.

RESULTS

At 5 y of age, the prevalence of ever eczema was 30.4%. Metabolites of di-isobutyl phthalate (DiBP) and di-isononyl phthalate (DiNP) were positively associated with early-onset (0-24 mo of age) eczema (15.7%) and late-onset (24-60 mo of age) eczema (14.7%). Applying the Cox's model showed a significant association of occurrence of eczema in the first 5 y of life with DiBP and DiNP metabolites. Among IgE-sensitized boys, metabolites of di-n-butyl phthalate (DBP) and DiBP were significantly associated with ever eczema {hazard ratio (HR)=1.67 [95% confidence interval (CI): 1.10, 2.54], p=0.01 and HR=1.87 (95% CI: 1.01, 3.48), p=0.04, respectively}.

CONCLUSIONS

Occurrence of eczema in early childhood may be influenced by prenatal exposure to certain phthalates in boys. Further investigations are needed to confirm this observation. https://doi.org/10.1289/EHP1829.

Predicting the atopic march: Results from the Canadian Healthy Infant Longitudinal Development Study

BACKGROUND

The atopic march describes the progression from atopic dermatitis during infancy to asthma and allergic rhinitis in later childhood. In a Canadian birth cohort we investigated whether concomitant allergic sensitization enhances subsequent development of these allergic diseases at age 3 years.

METHODS

Children completed skin prick testing at age 1 year. Children were considered sensitized if they produced a wheal 2 mm or larger than that elicited by the negative control to any of 10 inhalant or food allergens. Children were also assessed for atopic dermatitis by using the diagnostic criteria of the UK Working Party. At age 3 years, children were assessed for asthma, allergic rhinitis, food allergy, and atopic dermatitis. Data from 2311 children were available.

RESULTS

Atopic dermatitis without allergic sensitization was not associated with an increased risk of asthma at age 3 years after adjusting for common confounders (relative risk [RR], 0.46; 95% CI, 0.11-1.93). Conversely, atopic dermatitis with allergic sensitization increased the risk of asthma more than 7-fold (RR, 7.04; 95% CI, 4.13-11.99). Atopic dermatitis and allergic sensitization had significant interactions on both the additive (relative excess risk due to interaction, 5.06; 95% CI, 1.33-11.04) and multiplicative (ratio of RRs, 5.80; 95% CI, 1.20-27.83) scales in association with asthma risk. There was also a positive additive interaction between atopic dermatitis and allergic sensitization in their effects on food allergy risk (relative excess risk due to interaction, 15.11; 95% CI, 4.19-35.36).

CONCLUSIONS

Atopic dermatitis without concomitant allergic sensitization was not associated with an increased risk of asthma. In combination, atopic dermatitis and allergic sensitization had strong interactive effects on both asthma and food allergy risk at age 3 years.

Risks for comorbidity in children with atopic disorders: an observational study in Dutch general practices

OBJECTIVE

This study aimed to investigate both atopic and non-atopic comorbid symptoms and diseases in children with physician-diagnosed atopic disorders (atopic eczema, asthma and allergic rhinitis).

METHODS

All children aged 0-18 years listed in a nationwide primary care database (the Netherlands Institute for Health Services Research-Primary Care Database) with routinely collected healthcare data in 2014 were selected. Children with atopic disorders were matched on age and gender with non-atopic controls within the same general practice. A total of 404 International Classification of Primary Care codes were examined. Logistic regression analyses were performed to examine the associations between the presence of atopic disorders and (non-)atopic symptoms and diseases by calculating ORs.

RESULTS

Having one of the atopic disorders significantly increased the risk of having other atopic-related symptoms, even if the child was not registered as having the related atopic disorder. Regarding non-atopic comorbidity, children with atopic eczema (n=15 530) were at significantly increased risk for (infectious) skin diseases (OR: 1.2-3.4). Airway symptoms or (infectious) diseases (OR: 2.1-10.3) were observed significantly more frequently in children with asthma (n=7887). Children with allergic rhinitis (n=6835) had a significantly distinctive risk of ear-nose-throat-related symptoms and diseases (OR: 1.5-3.9). Neither age nor gender explained these increased risks.

CONCLUSION

General practitioners are not always fully aware of relevant atopic and non-atopic comorbidity. In children known to have at least one atopic disorder, specific attention is required to avoid possible insufficient treatment and unnecessary loss of quality of life.

International consensus (ICON) on: clinical consequences of mite hypersensitivity, a global problem

Since mite allergens are the most relevant inducers of allergic diseases worldwide, resulting in significant morbidity and increased burden on health services, the International Collaboration in Asthma, Allergy and Immunology (iCAALL), formed by the American Academy of Allergy, Asthma and Immunology (AAAAI), the American College of Allergy, Asthma and Immunology (ACAAI), the European Academy of Allergy and Clinical Immunology (EAACI), and the World Allergy Organization (WAO), has proposed to issue an International Consensus (ICON) on the clinical consequences of mite hypersensitivity. The objectives of this document are to highlight aspects of mite biology that are clinically relevant, to update the current knowledge on mite allergens, routes of sensitization, the genetics of IgE responses to mites, the epidemiologic aspects of mite hypersensitivity, the clinical pictures induced by mites, the diagnosis, specific immunotherapeutic approaches, and prevention.