Development of allergies and asthma in infants and young children with atopic dermatitis--a prospective follow-up to 7 years of age

Dupilumab Safety and Efficacy up to 1 Year in Children Aged 6 Months to 5 Years with Atopic Dermatitis: Results from a Phase 3 Open-Label Extension Study

BACKGROUND

Pediatric patients with moderate-to-severe atopic dermatitis (AD) often experience a high disease burden and have a high risk of persistent disease. Standard-of-care immunosuppressive systemic treatments have been used off-label for AD in pediatric patients despite concerns for suboptimal safety with continuous use and risk of relapse upon discontinuation. The biologic agent dupilumab is the first systemic treatment approved for moderate-to-severe AD in children as young as 6 months. Long-term safety and efficacy data in this patient population are needed to inform continuous AD management.

OBJECTIVES

The purpose of this work was to determine the long-term safety and efficacy of dupilumab treatment up to 1 year in an open-label extension (OLE) study [LIBERTY AD PED-OLE (NCT02612454)] in children aged 6 months to 5 years with moderate-to-severe AD who previously participated in the 16-week, double-blind, phase 3 LIBERTY AD PRESCHOOL trial (NCT03346434 part B; parent study) and were subsequently enrolled in PED-OLE.

METHODS

In PED-OLE, patients received dupilumab every 4 weeks according to a weight-tiered regimen (body weight ≥ 5 kg to < 15 kg: 200 mg; ≥ 15 kg to < 30 kg: 300 mg).

RESULTS

Data for 142 patients were analyzed, 60 of whom had completed the 52-week visit at time of database lock. Mean age at baseline was 4.1 y [SD, 1.13; range, 1.0-5.9 years]. A majority (78.2%) of patients reported ≥ 1 treatment-emergent adverse event (TEAE), most of which were mild or moderate and transient. The most frequently reported TEAEs were nasopharyngitis (19.7%), cough (15.5%), and pyrexia (14.1%). One TEAE led to treatment discontinuation (severe urticaria, which resolved in 1 day). By week 52, 36.2% of patients had achieved an Investigator's Global Assessment score of 0/1 (clear/almost clear skin), and 96.6%, 79.3%, and 58.6% had at least 50%, 75%, or 90% improvement, respectively, in Eczema Area and Severity Index scores.

CONCLUSIONS

Consistent with results seen in adults, adolescents, and older children (aged 6-11 years), treatment with dupilumab for up to 1 year in children aged 6 months to 5 years with inadequately controlled moderate-to-severe AD demonstrated an acceptable long-term safety profile and sustained efficacy. These results support the long-term continuous use of dupilumab in this patient population.

TRIAL REGISTRATION

ClinicalTrials.gov Identifiers: NCT02612454 and NCT03346434 (part B).

Infant lung function and early skin barrier impairment in the development of asthma at age 3 years

BACKGROUND

Largely unexplored, we investigated if lower lung function, impaired skin barrier function by transepidermal water loss (TEWL), eczema, and filaggrin (FLG) mutations in infancy were associated with asthma in early childhood.

METHODS

From the factorially designed randomized controlled intervention study PreventADALL, we evaluated 1337/2394 children from all randomization groups with information on asthma at age 3 years, and at age 3 months either lung function, TEWL, eczema, and/or FLG mutations. Lower lung function was defined as the time to peak tidal expiratory flow to expiratory time (tPTEF /tE ) <0.25, and skin barrier impairment as a high TEWL >9.50 g/m2 /h. Eczema was clinically observed, and DNA genotyped for FLG mutations. Asthma was defined as asthma-like symptoms (≥3 episodes of bronchial obstruction) between age 2-3 years as well as a history of doctor-diagnosed asthma and/or asthma medication use. Associations were analyzed in logistic regression models, presented with adjusted ORs (aOR) and 95% confidence intervals (CI).

RESULTS

Lower lung function and skin barrier impairment were associated with asthma in general; aOR (95% CI) 5.4 (2.1, 13.7) and 1.6 (1.1, 2.5), while eczema and FLG mutations were associated with asthma in children with atopic dermatitis or allergic sensitization only. Stratifying for sex, the risk of asthma was only increased in boys with lower lung function; aOR (95% CI) 7.7 (2.5, 23.6), and in girls with FLG mutations; aOR (95% CI) 3.5 (1.5, 8.2).

CONCLUSION

Lower lung function and impaired skin barrier function in infancy may increase the risk of asthma at age 3 years.

The relationship between childhood atopic dermatitis and asthma in an under resourced community

Background: Atopic dermatitis (AD) is an inflammatory skin disease caused by allergen exposures and estimated to affect ∼20% of children. Children in urban areas have a higher prevalence of AD compared with those living outside of urban areas. AD is believed to lead to asthma development as part of the "atopic march." Objective: Our objective was to determine the sequential and chronological relationships between AD and asthma for children in an under-resourced community. Methods: The progression from AD to asthma in the under-resourced, urban community of Sun Valley, Colorado, was examined by assessing Medicaid data for the years 2016 to 2019 for a diagnosis of AD or asthma in children 6 and 7 years old. Results: Pearson correlations between AD and asthma diagnoses were significant only with respect to AD at age 6 years compared with asthma 1 year later, at age 7 years. Conclusion: By studying a susceptible community with a consistent but mixed genetic background, we found sequential and chronological links between AD and asthma.

Atopic Dermatitis: Disease Background and Risk Factors

Multiple risk factors have been associated with the development of atopic dermatitis (AD). Recent advances in understanding the role of genetics in this disease have been made, with discovery of the filaggrin (FLG) gene as the most notable so far. In addition to FLG gene mutations as a risk factor for AD, a positive family history of atopic or allergic disease in either parent has been shown to confer a greater risk of developing AD. Atopic dermatitis usually presents early in life and is thought to represent the initial step in the "atopic march," which is characterized by the development of other atopic diseases later in life such as asthma, allergic rhinitis, and/or rhinoconjunctivitis, food allergies, and hay fever. Other comorbid diseases that have been associated with AD include increase risk of viral and bacterial skin infections, neuropsychiatric diseases such as attention-deficit hyperactivity disorders (ADHD), and autistic spectrum disorder (ASD). Patients with AD have also been found to have worse sleep quality overall compared to patients without AD. In this chapter, we will discuss the risk factors associated with development of atopic dermatitis as well as the most commonly reported comorbidities in patients with this disease.

Efficacy and safety of abrocitinib in patients with moderate-to-severe atopic dermatitis and comorbid allergies

BACKGROUND

Abrocitinib efficacy by comorbidity status in patients with moderate-to-severe atopic dermatitis (AD) has not been previously assessed. This post hoc analysis evaluated the efficacy and safety of abrocitinib in patients with AD and allergic comorbidities.

METHODS

Data were pooled from patients who received abrocitinib 200 mg, 100 mg, or placebo in phase 2b (NCT02780167) and phase 3 (NCT03349060, NCT03575871) monotherapy trials. Patients with and without allergic comorbidities (allergic asthma, rhinitis, conjunctivitis, or food allergy) were evaluated for Investigator's Global Assessment (IGA) response (clear [0] or almost clear [1]), ≥75% improvement in the Eczema Area and Severity Index (EASI-75), ≥4-point improvement in Peak Pruritus Numerical Rating Scale (PP-NRS4), and Dermatology Life Quality Index (DLQI) response (<2 with baseline score ≥2). Other outcomes were Patient-Oriented Eczema Measure (POEM), SCORing Atopic Dermatitis (SCORAD), Pruritus and Symptoms Assessment for Atopic Dermatitis (PSAAD), and treatment-emergent adverse events (TEAEs).

RESULTS

Of 942 patients, 498 (53%) reported at least one allergic comorbidity (asthma only, 33%; conjunctivitis only or rhinitis only or both, 17%; food allergies only, 15%; >1 allergic comorbidity, 34%). Regardless of comorbidity status, from Week 2 to Week 12, higher percentages of patients treated with either abrocitinib dose achieved IGA 0/1, EASI-75, PP-NRS4, or DLQI 0/1 versus placebo-treated patients. Changes from baseline in POEM, SCORAD, and PSAAD were greater with abrocitinib than with placebo in patients with and without allergic comorbidities. Most TEAEs were mild or moderate.

CONCLUSIONS

Efficacy and safety data support abrocitinib use to manage AD in patients with or without allergic comorbidities.

Allergic Rhinitis

Allergic rhinitis (AR) affects more than 400 million people worldwide, making it 1 of the most prevalent chronic diseases. Childhood AR is increasing, and almost half of patients with AR develop symptoms before age 6 years. Although a diagnosis of AR is associated with higher socioeconomic status, underserved and urban populations have more indoor aeroallergen sensitizations and are likely underdiagnosed with AR, further exacerbating health-care disparities. AR negatively impacts quality of life, school performance, and overall health outcomes. Untreated AR in children increases the risk for poor asthma control, increased asthma severity, and exacerbations. Many patients believe that they have seasonal allergies only but in reality have both perennial and seasonal AR, which may change the approach to allergen avoidance measures and treatment recommendations. Pharmacotherapy of AR has expanded, with many intranasal corticosteroids, intranasal antihistamines, and second-generation oral antihistamines approved for pediatric use. Allergen immunotherapy, including both subcutaneous and sublingual forms, are approved for children and are disease modifying, potentially reducing further allergen sensitization and progression to asthma. Many of the currently available biological therapies indicated for pediatric asthma and/or atopic diseases reduce AR symptoms as well. Children with moderate to severe or refractory AR or those with comorbidities should be referred to allergists for diagnostic testing and expanded management options, including immunotherapy and potential biological treatment.

Beyond the Skin: Reduced Lung Function Associated With Atopic Dermatitis in Infants

BACKGROUND

Very few studies have examined lung function parameters using tidal breath analysis (TBA) in atopic dermatitis (AD) with its high potential for progression to asthma.

OBJECTIVE

To measure lung functions using TBA in infants with AD and in healthy controls (HCs), and to investigate the effects of disease severity, food sensitivity, and history of recurrent wheezing on TBA parameters in infants with AD.

METHODS

Two hundred thirty infants were included in this prospective cross-sectional study, including an AD group (n = 150) and an HC group (n = 80). Food sensitivity was assessed by means of food-specific IgE or the skin prick test. The severity of the disease was evaluated using the SCORing Atopic Dermatitis. Lung function was assessed using TBA.

RESULTS

The following TBA parameters were significantly lower in the AD group than in the HC group (P < .05): time to peak tidal expiratory flow, exhaled volume to peak tidal expiratory flow, ratio of time to peak tidal expiratory flow to expiratory time, ratio of exhaled volume to peak tidal expiratory flow to total expiratory volume, expiratory flow when 25% of tidal volume remains in the lungs, respiratory rate, and minute ventilation. No difference was observed in the AD group when TBA parameters were compared according to disease severity, food sensitivity, and history of recurrent wheezing (P > .05). The receiver-operating characteristic curve demonstrated by the ratio of time to peak tidal expiratory flow to expiratory time yielded an area under the curve of 0.826 (CI, 0.772-0.879), with a cutoff value of 31.65 or higher in differentiating AD, with a sensitivity of 78.7% and a specificity of 77.5%.

CONCLUSIONS

TBA curves can be a useful tool for demonstrating expiratory airway obstruction in AD and for providing objective information for the clinician. Bronchial obstruction was detected in young children with AD irrespective of the severity of the disease, food sensitivity, and history of recurrent wheezing.

Risk factors predisposing children to food allergies

BACKGROUND

Food allergies are the most common cause of anaphylaxis in children, and their incidence is increasing globally. The aim of this study was to determine the risk factors leading to food allergies in childhood.

METHODS

Children with food allergies and non-atopic healthy children were compared using a questionnaire that included prenatal, neonatal, and postnatal risk factors.

RESULTS

A total of 314 subjects, 155 patients and 159 healthy children for the control group, were enrolled in the study. The median age of patients with a food allergy at diagnosis was 6 months (1-156 months), and 71 patients (45.8%) were males. The median age of the control group was 12 months (1-61 months), and 67.0% were males. Older maternal age (P = 0.023), birth by caesarean section (P = 0.001), birth in the summer or autumn (P = 0.011), crowded housing (P = 0.001), damp houses (P = 0.001), being fed with breast milk and complementary food (P = 0.001), use of synthetic bedding (P = 0.024), and being the oldest child in the family (P = 0.001) were the considered risk factors for an immunoglobulin-E (IgE)-mediated food allergy. A low frequency of yoghurt consumption by mother (P = 0.001) and use of wool bedding (P = 0.018) were identified as risk factors for non-IgE-mediated food allergies. Low socioeconomic status (P = 0.001) played a protective role against both IgE- and non-IgE-mediated food allergies whereas breastfeeding played a protective role against IgE-mediated food allergies (P = 0.030).

CONCLUSION

The most important aspect of this study was that it separately identified prenatal, neonatal, and postnatal risk factors for IgE- and non-IgE-mediated food allergies.

Disease modification in inflammatory skin disorders: opportunities and challenges

Progress in understanding of the mechanisms underlying chronic inflammatory skin disorders, such as atopic dermatitis and psoriasis vulgaris, has led to new treatment options with the primary goal of alleviating symptoms. In addition, this knowledge has the potential to inform on new strategies aimed at inducing deep and therapy-free remission, that is, disease modification, potentially impacting on associated comorbidities. However, to reach this goal, key areas require further exploration, including the definitions of disease modification and disease activity index, further understanding of disease mechanisms and systemic spillover effects, potential windows of opportunity, biomarkers for patient stratification and successful intervention, as well as appropriate study design. This Perspective article assesses the opportunities and challenges in the discovery and development of disease-modifying therapies for chronic inflammatory skin disorders.

Attenuating the atopic march: Meta-analysis of the dupilumab atopic dermatitis database for incident allergic events

BACKGROUND

Atopic march refers to the sequential development of allergic diseases from infancy through adolescence, typically beginning with atopic dermatitis (AD), followed by food allergy and then airway diseases, later evolving to broader or worsened spectrum of allergic diatheses. No intervention has shown to alter its course.

OBJECTIVE

We sought to determine the rate of acquisition of new or worsened allergic events for dupilumab versus placebo in patients with AD.

METHODS

Allergy-associated events from 12 clinical trials were grouped into 17 allergy categories, and IgE changes from baseline were defined. A new/worsened event was considered one step of atopic march. Treatment effect was assessed by incidence rate ratios (IRRs), dupilumab versus placebo, by meta-analysis.

RESULTS

The duration of pooled AD studies was 4 to 52 weeks (1359 patient-years; n = 2296 dupilumab, n = 1229 placebo, median age 35 years). The median age at AD onset was 2 years. Baseline allergic disease burden was comparable between groups. Dupilumab reduced the risk of new/worsening allergies by 34% (IRR 0.66; 95% confidence interval [CI], 0.52-0.84) and new allergies by 37% (IRR 0.63; 95% CI, 0.48-0.83) versus placebo. Including IgE category shift, the IRR for combined new/worsening allergies was reduced by 54% (IRR 0.46; 95% CI, 0.36-0.57). These treatment benefits did not reverse on treatment discontinuation in off-treatment follow-up.

CONCLUSIONS

The acquisition/worsening of allergic conditions suggestive of atopic march was observed in a pooled adult/adolescent AD study population with inadequately controlled AD. Treatment with dupilumab reduced new/worsened allergy events versus placebo; inclusion of IgE category change increased the apparent benefit.

Environmental Exposures may Hold the Key; Impact of Air Pollution, Greenness, and Rural/Farm Lifestyle on Allergic Outcomes

PURPOSE OF REVIEW

There has been an increased prevalence of allergy. Due to this relatively rapid rise, changes in environmental exposures are likely the main contributor. In this review, we highlight literature from the last 3 years pertaining to the role of air pollution, greenness, and the rural/farm lifestyle and their association with the development of allergic sensitization, atopic dermatitis, food allergy, and allergic rhinitis in infancy and childhood. Because asthma has a more complex pathophysiology, it was excluded from this review.

RECENT FINDINGS

Recent studies support a role for air pollution, greenness, and rural/farming lifestyle influencing atopic outcomes that continue to be defined. While many studies have examined singular environmental exposures, the interconnectedness of these exposures and others points to a need for future work to consider an individual's whole exposure. Environmental exposures' influence on atopic disease development remains an ongoing and important area of study.

Trends (2007-2019) of major atopic diseases throughout the life span in a large Mexican population

Background

Major atopic diseases such as atopic dermatitis (AD), allergic rhinitis (AR), and asthma share the same atopic background, but they often show differences in their epidemiological behavior.

Objective

We aimed to report the profile of these atopic diseases in a large Mexican population, including their age-related incidences, male:female (M:F) ratios, recent time trends, and association with altitude.

Methods

Registries from the largest, nationwide health institution in Mexico (more than 34 million insured subjects), were reviewed. New cases of AD, AR, and asthma diagnosed each year by family physicians from 2007 to 2019 were adjusted by the corresponding insured population to estimate incidence rates.

Results

Incidences of the 3 atopic diseases were highest in the 0-4 years age-group and progressively decreased thereafter until adolescence. Asthma and AR, but not AD, were more frequent in males during childhood (M:F ratios of 1.5, 1.3, and 0.95, respectively), but predominated in females during adulthood (M:F ratios of 0.52, 0.68, and 0.73, respectively). Time trends showed an initial increasing trend of annual incidences, with a peak around 2009-2011, and a downward trend afterward. This decreasing trend was seen in all age-groups and was more evident for AD (∼50% drop) and asthma (∼40% drop) than for AR (∼20% drop). Geographical distribution suggested that incidences of asthma and AR, but not of AD, had an inverse association with altitude.

Conclusion

Annual incidences of the 3 major atopic diseases have declined in recent years in almost all age groups, and their epidemiological profile during the life span showed contrasting differences according to age, sex, and ecological association with altitude, mainly regarding AD.

Biomarkers associated with the development of comorbidities in patients with atopic dermatitis: A systematic review

Biomarkers associated with the development of comorbidities in atopic dermatitis (AD) patients have been reported, but have not yet been systematically reviewed. Seven electronic databases were searched, from database inception to September 2021. English language randomized controlled trials, prospective and retrospective cohort, and case-control studies that investigated the association between a biomarker and the development of comorbidities in AD patients were included. Two authors independently screened the records for eligibility, one extracted all data, and critically appraised the quality of studies and risk of bias. Fifty six articles met the inclusion criteria, evaluating 146 candidate biomarkers. The most frequently reported biomarkers were filaggrin mutations and allergen specific-IgE. Promising biomarkers include specific-IgE and/or skin prick tests predicting the development of asthma, and genetic polymorphisms predicting the occurrence of eczema herpeticum. The identified studies and biomarkers were highly heterogeneous, and associated with predominately moderate-to-high risk of bias across multiple domains. Overall, findings were inconsistent. High-quality studies assessing biomarkers associated with the development of comorbidities in people with AD are lacking. Harmonized datasets and independent validation studies are urgently needed.

Association of Severe Bronchiolitis during Infancy with Childhood Asthma Development: An Analysis of the ECHO Consortium

Objective: Many studies have shown that severe (hospitalized) bronchiolitis during infancy is a risk factor for developing childhood asthma. However, the population subgroups at the highest risk remain unclear. Using large nationwide pediatric cohort data, namely the NIH Environmental influences on Child Health Outcomes (ECHO) Program, we aimed to quantify the longitudinal relationship of bronchiolitis hospitalization during infancy with asthma in a generalizable dataset and to examine potential heterogeneity in terms of major demographics and clinical factors. Methods: We analyzed data from infants (age <12 months) enrolled in one of the 53 prospective cohort studies in the ECHO Program during 2001−2021. The exposure was bronchiolitis hospitalization during infancy. The outcome was a diagnosis of asthma by a physician by age 12 years. We examined their longitudinal association and determined the potential effect modifications of major demographic factors. Results: The analytic cohort consisted of 11,762 infants, 10% of whom had bronchiolitis hospitalization. Overall, 15% subsequently developed asthma. In the Cox proportional hazards model adjusting for 10 patient-level factors, compared with the no-bronchiolitis hospitalization group, the bronchiolitis hospitalization group had a significantly higher rate of asthma (14% vs. 24%, HR = 2.77, 95%CI = 2.24−3.43, p < 0.001). There was significant heterogeneity by race and ethnicity (Pinteraction = 0.02). The magnitude of the association was greater in non-Hispanic White (HR = 3.77, 95%CI = 2.74−5.18, p < 0.001) and non-Hispanic Black (HR = 2.39, 95%CI = 1.60−3.56; p < 0.001) infants, compared with Hispanic infants (HR = 1.51, 95%CI = 0.77−2.95, p = 0.23). Conclusions: According to the nationwide cohort data, infants hospitalized with bronchiolitis are at a higher risk for asthma, with quantitative heterogeneity in different racial and ethnic groups.

Prevalence and Influencing Risk Factors of Eczema Among Preschool Children in Hail City

Background Eczema is a common inflammatory skin disorder in the pediatric population. Although eczema is a significant public health issue with negative impacts on quality of life, studies looking at the prevalence and risk factors among preschool-aged children in Saudi Arabia are limited. Methods A descriptive, cross-sectional, online-based study was conducted among parents of preschool children in Hail City, Saudi Arabia, between July 2022 and September 2022. The self-administered, pre-tested questionnaire was distributed on social media networks for data gathering, which was subsequently analyzed using Statistical Package for the Social Sciences (SPSS, IBM Corp., Armonk, NY) software. Results Among 964 preschool children, 54.5% of the children have been diagnosed with eczema. A total of 152 (60.1%) male children had eczema compared to 231 (59.8%) female children, while 142 (43.7%) parents had children of both genders diagnosed with eczema (P = 0.001). Multivariate logistic regression showed that male gender (odds ratio [OR] = 1.41, 95% confidence interval = 1.16-1.71), smoking in the house (OR = 1.85, 95%CI = 1.37-2.50), presence of mold or dampness in the house while the mother was pregnant (OR = 1.95, 95%CI = 1.17-3.24), house renovation during the mother's pregnancy (OR = 1.54, 95%CI = 1.01-2.34), use of an air conditioner (OR = 1.57, 95%CI = 1.07-2.30), and dry skin (OR = 5.83, 95%CI = 4.27-7.96) were significant predictors for the development of eczema. Conclusion The high prevalence of eczema among preschool-aged children in Hail indicates the need for parents to take action at the household level and beyond to successfully lower the risk of eczema development in the region.

Effect of early atopic sensitization in children aged 0-2 years on the development of asthma symptoms at 9-11 years of age

BACKGROUND

Personal genetic predisposition and early life environmental factors are important for the development of childhood asthma. We aimed to search whether egg, milk and mite sensitizations at 0-2 years old are risk factors for asthma symptoms at 9-11 years old.

METHODS

A total of 210 wheezer children who had specific immunoglobulin (Ig) E in 2010-2012 were included in the study (followed by pediatric allergy). Patients were divided into non-atopic (group 1, n = 157) and atopic patients [groups 2-7, n = 53 (5 patients were in both group 4 and group 5)] based on sensitizations. Using the International Study of Asthma and Allergy in Childhood questionnaire, current wheeze (CW, 2nd question), exercise wheezing (EW, 7th question), and dry cough (DC, 8th question) were surveyed. Also, parental allergies, eczema at 0-2 years, current eosinophil percentage and total IgE were recorded.

RESULTS

Eczema was observed as an important risk factor [CW: odds ratio (OR) = 2.83, 95% confidence interval (CI) = 1.54-5.23, P ≤ 0.001; EW: OR = 2.71, 95% CI = 1.33-5.54, P = 0.006; DC: OR = 3.03, 95% CI = 1.47-6.25, P = 0.003], whereas having no atopic sensitization at 0-2-year-old (group 1) was found as a significant protective factor for asthma at 9-11 years old (CW: OR = 0.32, 95% CI = 0.15-0.70, P = 0.004; EW: OR = 0.21, 95% CI 0.10-0.44, P ≤ 0.001; DC: OR = 0.25, 95% CI = 0.10-0.59, P = 0.002).

CONCLUSION

Early personal eczema is a significant risk factor for the development of asthma symptoms at 9-11 years old, whereas not having an allergic sensitization at 0-2 years old (group 1) is an important protective factor.

The Acari Hypothesis, III: Atopic Dermatitis

Atopic dermatitis is a chronic relapsing dermatopathology involving IgE against allergenic materials present on mammalian epithelial surfaces. Allergens are as diverse as pet danders, and polypeptides expressed by microbes of the mammalian microbiome, e.g., Malassezia spp. The Acari Hypothesis posits that the mammalian innate immune system utilizes pathogen-bound acarian immune effectors to protect against the vectorial threat posed by mites and ticks. Per The Hypothesis, IgE-mediated allergic disease is a specious consequence of the pairing of acarian gastrointestinal materials, e.g., allergenic foodstuffs, with acarian innate immune effectors that have interspecies operability. In keeping with The Hypothesis, the IgE profile of atopic patients should include both anti-acarian antibodies and specious antibodies responsible for specific allergy. Further, the profile should inform on the diet and/or environment of the acarian vector. In this regard, the prevalence of Demodex and Dermatophagoides on the skin of persons suffering from atopic dermatitis is increased. Importantly, the diets of these mites correspond well with the allergens of affected patients. In this report, roles for these specific acarians in the pathogenesis of atopic dermatitis are proposed and elaborated.

Time-trends for eczema prevalences among children and adults from 1985 to 2015 in China: a systematic review

Background

Several studies have reported that childhood prevalence of eczema has been increasing worldwide. However, none study quantitatively evaluated prevalence trends of eczema among children and adults in the last 30 years in China.

Methods and Findings

Via a systematic review of literature databases in English and Chinese, we summarized all studies reporting eczema prevalences from 1985 to 2015 in China as well as diagramed prevalence and eczematous population trends against year for different age groups. A total of 93 studies and 17 studies (16 for children and one for adults) were selected for qualitative and quantitative synthesis, respectively. Childhood lifetime-ever eczema prevalences ranged from 10.0% to 30.0%. Prevalences among 3-12-year-olds children showed increasing trends in most specific cities, but national lifetime-ever eczema prevalences among 13-14-year-olds children decreased from 10.6% in 2001 to 8.6% in 2009 in mainland China. We estimated that about 1.5 million children aged 13-14-year-olds in 2009 and 15.5 million children aged 3-6-year-olds in 2012 had lifetime-ever eczema in mainland China. Similar studies were too few to ascertain time-trends of eczema prevalence among adults. About 39.4, 20.0, and 11.6 million adults aged 15-86-year-olds in 2010 had contact dermatitis, seborrheic dermatitis, and atopic dermatitis in the mainland China, respectively.

Conclusions

The burden of eczema became heavier in young children, whereas perhaps had been reduced in adolescent in China. More studies for eczema prevalence in adults are warranted.

Revisiting the Roles of Filaggrin in Atopic Dermatitis

The discovery in 2006 that loss-of-function mutations in the filaggrin gene (FLG) cause ichthyosis vulgaris and can predispose to atopic dermatitis (AD) galvanized the dermatology research community and shed new light on a skin protein that was first identified in 1981. However, although outstanding work has uncovered several key functions of filaggrin in epidermal homeostasis, a comprehensive understanding of how filaggrin deficiency contributes to AD is still incomplete, including details of the upstream factors that lead to the reduced amounts of filaggrin, regardless of genotype. In this review, we re-evaluate data focusing on the roles of filaggrin in the epidermis, as well as in AD. Filaggrin is important for alignment of keratin intermediate filaments, control of keratinocyte shape, and maintenance of epidermal texture via production of water-retaining molecules. Moreover, filaggrin deficiency leads to cellular abnormalities in keratinocytes and induces subtle epidermal barrier impairment that is sufficient enough to facilitate the ingress of certain exogenous molecules into the epidermis. However, although FLG null mutations regulate skin moisture in non-lesional AD skin, filaggrin deficiency per se does not lead to the neutralization of skin surface pH or to excessive transepidermal water loss in atopic skin. Separating facts from chaff regarding the functions of filaggrin in the epidermis is necessary for the design efficacious therapies to treat dry and atopic skin.

Differences between pediatric and adult atopic dermatitis

Atopic dermatitis (AD) is a common disease with a broad spectrum of clinical manifestations. AD can manifest differently in adults than children. Core AD features are similar between children and adults overall, including lesions affecting flexural areas, presence of atopy, and xerosis. Adults have more signs of chronic disease, higher prevalence and different patterns of hand eczema, and a stronger relationship of disease activity with emotional factors, whereas children with AD have more exudative lesions, perifollicular accentuation, pityriasis alba, Dennie-Morgan folds, and seborrheic dermatitis-like presentation. These differences may be due in part to pathophysiologic differences in AD in children compared with adults. Atopic diseases commonly co-occur with AD, although most do not temporally have the "atopic march." Further research is warranted to better understand the differential roles of immune dysregulation, epidermal-barrier disruption, and dysbiosis between children and adults and determine whether such differences translate into differences in therapeutic efficacy.

Optimizing emollient therapy for skin barrier repair in atopic dermatitis

OBJECTIVE

We compared the principal characteristics of over-the-counter moisturizers with physiological lipid-based barrier repair therapy (BRT).

DATA SOURCES

An extended literature reported that moisturizers are considered standard ancillary therapy for anti-inflammatory skin disorders such as atopic dermatitis (AD). Additional studies have found that physiological lipid-based BRT can comprise effective, stand-alone therapy for pediatric AD.

RESULTS

Not all moisturizers are beneficial-some negatively impact skin function, and in doing so, they risk inducing or exacerbating inflammation in patients with AD. The frequent self-reported occurrences of sensitive skin in patients with AD could reflect the potential toxicity of such formulations. A still unanswered question is whether improper formulations could also prove to be counterproductive in other types of sensitive skin, such as rosacea. In contrast, we found how physiological lipid-based BRT (when comprised of the 3 key stratum corneum lipids in sufficient quantities and at an appropriate molar ratio) can correct the barrier abnormality, thereby reducing inflammation in AD and possibly in other inflammatory dermatoses, such as adult eczemas and possibly even psoriasis.

CONCLUSION

We provide guidelines for the appropriate dispensation of moisturizers and physiological lipid-based, BRT for the treatment of AD. Both over-the-counter (Atopalm) and prescription (EpiCeram) products are available in the United States with these characteristics.

Preventing allergies through the skin

OBJECTIVE

To inform readers of the current and forthcoming skin barrier interventions that have clinically relevant implications in the prevention of allergic sensitization and atopic diseases.

DATA SOURCES

Peer-reviewed journal articles indexed on PubMed and clinical trials referenced on clinicaltrials.gov were analyzed.

STUDY SELECTIONS

Literature searches from PubMed and clinicaltrials.gov were performed using combinations of the following search terms: prevention, allergy, atopy, skin, cutaneous, microbiome, microbiota, Staphylococcus aureus, atopic dermatitis, eczema, food allergy, and asthma.

RESULTS

The skin barrier represents an entry point for allergic sensitization and T_H2-mediated allergic disorders. Results from clinical trials designed to improve microbiome complexity and reduce S aureus colonization, provide skin barrier enhancement, and deliver epicutaneous immunotherapy are summarized and discussed in the context of primary, secondary, and tertiary prevention of allergic disease.

CONCLUSION

The skin barrier is a promising target for prevention of allergic disease, though clinical trial results thus far have been mixed, at best.

Association of heat shock protein 8 with atopic march in a murine experimental model

Background

Atopic march (AM), a unique characteristic of allergic diseases, refers to the sequential progression of atopic dermatitis (AD) in infants to allergic asthma and allergic rhinitis in children and young adults, respectively. Although there are several studies on AM, the establishment of an AM murine model to expand our understanding of the underlying mechanism and to identify the potential biomarkers is yet to be achieved. In this study, an improved murine model was established by applying a method to minimize skin irritation in inducing AD, and it was used to perform integrated analyses to discover candidate biomarkers.

Methods

To induce atopic dermatitis, 2,4-dinitrochlorobenzene (DNCB) was applied to the ear skin once a week, and this was continued for 5 weeks. From the second application of DNCB, Dermatophagoides pteronyssinus (Dp) extract was applied topically 2 days after each DNCB application; this was continued for 4 weeks. Dp sensitization and intranasal challenges were then performed for 4 weeks to develop conditions mimicking AM.

Results

Exacerbated airway inflammation and allergic responses observed in the AM-induced group suggested successful AM development in our model. Two-dimensional gel electrophoresis (2-DE) and mass spectrometry analysis identified 753 candidate proteins from 124 2-DE spots differentially expressed among the experimental groups. Functional analyses, such as Gene Ontology (GO) annotation and protein-protein interaction (PPI) analysis were conducted to investigate the relationship among the candidate proteins. Seventy-two GO terms were significant between the two groups; heat shock protein 8 (Hspa8) was found to be included in six of the top 10 GO terms. Hspa8 scored high on the PPI parameters as well.

Conclusion

We established an improved murine model for AM and proposed Hspa8 as a candidate biomarker for AM.

Increasing severity of early-onset atopic dermatitis, but not late-onset, associates with development of aeroallergen sensitization and allergic rhinitis in childhood

BACKGROUND

Early exposure to allergens through a defect skin barrier has been proposed as a mechanism for inducing sensitization and development of allergic diseases. We hypothesized that early-onset, severe atopic dermatitis (AD) is associated with development of aeroallergen sensitization and allergic rhinitis.

METHODS

We included 368 children from the Copenhagen Prospective Studies on Asthma in Childhood₂₀₀₀ (COPSAC₂₀₀₀ ) at-risk mother-child cohort. AD was diagnosed prospectively based on Hanifin&Rajka's criteria and severity assessed using the Scoring Atopic Dermatitis (SCORAD) index. Early-onset AD was defined as debut ≤1 year, late-onset as debut from 1-6 years. Aeroallergen sensitization and allergic rhinitis were diagnosed at ages 6-7 and 12 years. Associations between early-onset and late-onset AD and allergy endpoints were calculated using general estimating equations (GEE) models to compute the overall odds ratios (OR) for both time points.

RESULTS

Early-onset AD (yes/no) and severity (SCORAD) were associated with development of aeroallergen sensitization during childhood; GEE OR = 1.68 [1.08; 2.62], p = .02 and 1.08 [1.03; 1.12], p < .001, whereas late-onset AD showed a borderline significant association and late-onset severity showed no association; GEE OR = 1.65 [0.92; 2.94], p = .08 and 1.01 [0.97; 1.06], p = .55. The same trend was seen for allergic rhinitis with significant association between early-onset AD and allergic rhinitis; GEE OR = 1.56 [1.01; 2.41], p = .04 and severity; GEE OR = 1.09 [1.05; 1.13], p < .001, whereas late-onset AD showed no association. The effects on sensitization and rhinitis of early-onset versus late-onset AD severity were significantly different: p-interaction_{sensitization}  = .03 and p-interaction_rhinitis  < .01.

CONCLUSION

Increasing severity of early-onset AD, but not late-onset AD, associates with aeroallergen sensitization and allergic rhinitis later in childhood.

New Directions in Understanding Atopic March Starting from Atopic Dermatitis

Recent evidence showed that the postulated linear progression of the atopic march, from atopic dermatitis to food and respiratory allergies, does not capture the heterogeneity of allergic phenotypes, which are influenced by complex interactions between environmental, genetic, and psychosocial factors. Indeed, multiple atopic trajectories are possible in addition to the classic atopic march. Nevertheless, atopic dermatitis is often the first manifestation of an atopic march. Improved understanding of atopic dermatitis pathogenesis is warranted as this could represent a turning point in the prevention of atopic march. In this review, we outline the recent findings on the pathogenetic mechanisms leading to atopic dermatitis that could be targeted by intervention strategies for the prevention of atopic march.

Skin Microbiota in Atopic Dermatitis

The skin microbiota represents an ecosystem composed of numerous microbial species interacting with each other, as well as with host epithelial and immune cells. The microbiota provides health benefits to the host by supporting essential functions of the skin and inhibiting colonization with pathogens. However, the disturbance of the microbial balance can result in dysbiosis and promote skin diseases, such as atopic dermatitis (AD). This review provides a current overview of the skin microbiota involvement in AD and its complex interplay with host immune response mechanisms, as well as novel therapeutic strategies for treating AD focused on restoring skin microbial homeostasis.

Gut-derived short-chain fatty acids modulate skin barrier integrity by promoting keratinocyte metabolism and differentiation

Barrier integrity is central to the maintenance of healthy immunological homeostasis. Impaired skin barrier function is linked with enhanced allergen sensitization and the development of diseases such as atopic dermatitis (AD), which can precede the development of other allergic disorders, for example, food allergies and asthma. Epidemiological evidence indicates that children suffering from allergies have lower levels of dietary fibre-derived short-chain fatty acids (SCFA). Using an experimental model of AD-like skin inflammation, we report that a fermentable fibre-rich diet alleviates systemic allergen sensitization and disease severity. The gut-skin axis underpins this phenomenon through SCFA production, particularly butyrate, which strengthens skin barrier function by altering mitochondrial metabolism of epidermal keratinocytes and the production of key structural components. Our results demonstrate that dietary fibre and SCFA improve epidermal barrier integrity, ultimately limiting early allergen sensitization and disease development.The Graphical Abstract was designed using Servier Medical Art images ( https://smart.servier.com ).

Atopic March: Dermatologic perspectives

The progression of allergic diseases with the development of atopic dermatitis and food allergy in infancy and subsequent asthma and allergic rhinitis in the later childhood is known as 'atopic march'. There have been many arguments in favour of and against this concept. This article reviews the latest epidemiology, immunological mechanisms and translational implications in clinical practice and research, which is relevant to the dermatologists. The role of skin as a site of initiation and the potential for interventions on skin that may prevent subsequent allergic diseases is also highlighted.

Current Insights into Atopic March

The incidence of allergic diseases is increasing, and research on their epidemiology, pathophysiology, and the prevention of onset is urgently needed. The onset of allergic disease begins in infancy with atopic dermatitis and food allergy and develops into allergic asthma and allergic rhinitis in childhood; the process is defined as “atopic march”. Atopic march is caused by multiple immunological pathways, including allergen exposure, environmental pollutants, skin barrier dysfunction, type 2 inflammation, and oxidative stress, which promote the progression of atopic march. Using recent evidence, herein, we explain the involvement of allergic inflammatory conditions and oxidative stress in the process of atopic march, its epidemiology, and methods for prevention of onset.

Prevalence of type 2 inflammatory diseases in pediatric patients with atopic dermatitis: real-world evidence

BACKGROUND

Patients with atopic dermatitis (AD) are considered at increased risk of developing other type 2 inflammatory diseases. However, real-world evidence based on large US commercially insured pediatric populations is scarce.

OBJECTIVE

To use a large US claims database (IBM® MarketScan® 2013-2017) to assess prevalence and incidence of type 2 inflammatory diseases in pediatric AD patients.

METHODS

Pediatric AD patients were matched 1:1 to non-AD patients. Prevalence was assessed for conjunctivitis, rhinitis, urticaria, asthma, eosinophilic esophagitis and chronic rhinosinusitis/nasal polyps, 12 months post-index date (first AD diagnosis date for AD patients; a randomly selected outpatient visit for control patients). Incidence of other type 2 inflammatory diseases post-index was assessed among patients 0-2 years old.

RESULTS

244,776 AD and matched non-AD patients were selected. The prevalence and incidence of type 2 inflammatory diseases were higher among AD patients. Overall, the prevalence more than doubled for asthma, eosinophilic esophagitis, urticaria, and rhinitis, and increased with AD severity.

LIMITATIONS

AD identification based on billing diagnoses; observation period of only 12 months; limited to commercially insured patients CONCLUSION: The burden of type 2 inflammatory diseases in pediatric AD patients is substantial, highlighting the need to optimize management of AD and its numerous associated morbidities.

ITS2 Sequencing and Targeted Meta-Proteomics of Infant Gut Mycobiome Reveal the Functional Role of Rhodotorula sp. during Atopic Dermatitis Manifestation

Association between the gut mycobiome and atopic dermatitis was investigated in 9-12-month-old infants using metagenomics. Two groups of atopic dermatitis infants were classified according to their symptom development as outgrown (recovered) and persisted (still undergoing). The evenness and diversity of the mycobiome in the persisted group were higher than in the healthy and outgrown groups. Dysbiosis of the microbiome in the persisted group was observed by a reduction in the Ascomycota/Basidiomycota ratio. Five fungi were selected as markers from each sample group. In the persisted group, Rhodotorula sp. abundance increased significantly, while Wickerhamomyces sp. and Kodamaea sp. abundance increased in the healthy group, and Acremonium sp. and Rhizopus sp. abundance increased considerably in the outgrown group. Metaproteomic analysis revealed that the persisted group had a high abundance of fungal proteins, particularly those from Rhodotorula sp. Unique proteins such as RAN-binding protein 1 and glycerol kinase from Rhodotorula sp. were hypothesized to be related to atopic dermatitis manifestation in infants.

Thymic stromal lymphopoietin, skin barrier dysfunction, and the atopic march

OBJECTIVE

Atopic dermatitis often precedes the development of other atopic diseases, and the atopic march describes this temporal relationship in the natural history of these diseases. Although the pathophysiological mechanisms that underlie this relationship are poorly understood, epidemiologic and genetic data have suggested that the skin might be an important route of sensitization to allergens.

DATA SOURCES

Review of recent studies on the role of skin barrier defects in systemic allergen sensitization.

STUDY SELECTIONS

Recent publications on the relationship between skin barrier defects and expression of epithelial cell-derived cytokines.

RESULTS

Animal models have begun to elucidate on how skin barrier defects can lead to systemic allergen sensitization. Emerging data now suggest that epithelial cell-derived cytokines, such as thymic stromal lymphopoietin, drive the progression from atopic dermatitis to asthma and food allergy. Skin barrier defects can lead to induction of epithelial cell-derived cytokines, which in turn leads to the initiation and maintenance of allergic inflammation and the atopic march.

CONCLUSION

Development of new biologic drug targeting type 2 cytokines provides novel therapeutic interventions for atopic dermatitis.

One march, many paths: Insights into allergic march trajectories

OBJECTIVE

The classical allergic march model posits that atopy begins in infancy with atopic dermatitis and progresses to asthma and allergic rhinitis in a subset of individuals. The growing prevalence and severity of allergic diseases have prompted renewed interest in refining this model. This review outlines epidemiologic evidence for the existence of allergic march trajectories (distinct paths of atopy development in individuals); reviews the roles that genetics, environment, and disease endotypes play in determining trajectory outcomes; and discusses the clinical utility of the trajectory model.

DATA SOURCES

PubMed search of English-language articles and reviews without date limits pertaining to the epidemiology, genetics, and immunologic mechanisms of allergic march trajectories and disease endotypes.

STUDY SELECTIONS

Studies and reviews were selected based on their high quality and direct relevance to the review topic.

RESULTS

Recent work in the field has revealed that immunoglobulin E-mediated food allergy and eosinophilic esophagitis are components of the allergic march. Furthermore, the field is acknowledging that variability exists in the number and sequence of allergic manifestations that individuals develop. These allergic march pathways, or trajectories, are influenced by genetic, environmental, and psychosocial factors that are incompletely understood.

CONCLUSION

Continued elucidation of the landscape and origins of allergic march trajectories will inform efforts to personalize allergic disease prevention, diagnosis, and treatment.

Atopic Eczema: Pathophysiological Findings as the Beginning of a New Era of Therapeutic Options

Atopic eczema (AE) is a chronic inflammatory disease hallmarked by intense pruritus and eczematous lesions. It depicts one of the most common skin diseases affecting a major part of children and several percentages of adults.Both pathogenesis and pathophysiology are based on complex orchestrated interactions of skin barrier defects, immunological changes, the environment, and an abundance of other contributing factors. Frequently, AE displays the starting point for other allergic diseases such as allergic asthma and rhinoconjunctivitis. Additionally, the risk of developing food allergy is increased. Furthermore, the disease is accompanied by a susceptibility to bacterial, fungal, and viral infections. The development of new therapies received great impetus by an ample research of the pathophysiological mechanisms, leading to a new era in the treatment of severe atopic eczema due to targeted treatments, e.g. the IL-4R alpha specific monoclonal antibody dupilumab.This article provides an overview of the causative and pathophysiological characteristics, the clinical and diagnostic aspects as well as current and future therapeutical possibilities focusing allergic aspects contributing to the course of the disease.

Associations between maternal and environmental exposures on atopic disease in the offspring of mothers with asthma

Background and Objective

Available data on the impact of perinatal and environmental factors on atopic diseases in the offspring are sparse and conflicting. We, therefore, investigated the impact of these factors on the risk of atopic diseases in the offspring of women with asthma.

Methods

Pregnant women referred to give birth at Copenhagen University Hospital‐Hvidovre, Denmark, have since 2007 been invited to participate in the Management of Asthma during Pregnancy program. Women with diagnosed asthma, currently prescribed asthma medication, first visit to the respiratory out‐patient clinic within the first 18 weeks of pregnancy that completed an online questionnaire about atopic diseases in their child were included in the current study.

Results

Five hundred and seventy‐one pregnancies were included. Among the off‐spring, 113 children (21%) had doctor‐diagnosed asthma, 178 (31%) atopic dermatitis (AD), and 55 (32%) both AD and doctor‐diagnosed asthma. AD in the offspring was associated with having a dog at home (odds ratio [OR], 2.56; 95% confidence interval [CI], [1.40–4.67], p = .002), whereas having a cat at home was associated with a higher risk of asthma in the offspring (OR, 2.16; 95% CI, [1.14–4.11], p = .02). The associations remained significant after adjusting for maternal age, smoking status, allergy, treatment with inhaled corticosteroids, forced expiratory volume in 1 s less than 80% predicted, uncontrolled asthma, and history of pre‐pregnancy asthma exacerbations. No association was found between gestational weight gain (GWG) in first trimester and total GWG and atopic disease in the offspring.

Conclusion

Having pets at home is associated with AD and asthma in the offspring of mothers with asthma.

Mapping risk factors for cumulative life course impairment in patients with chronic skin diseases - a systematic review

Patients with chronic skin diseases suffer from physical and psychosocial impairments which can lead to a cumulative life-long burden. Therefore, the concept of cumulative life course impairment (CLCI) was introduced, referring to the non-reversible damage due to the persistent life-long burden. This systematic review (PROSPERO registry number: CRD42020179141) aimed at mapping the risk factors and the associated burden over time in patients with psoriasis, atopic dermatitis (AD) and hidradenitis suppurativa (HS). Three electronic databases were searched (date of the last search: December 2019). Studies with a longitudinal study design that assessed the association between a risk factor and the associated burden over time in patients with psoriasis, AD and HS were included. Quality assessment of the included studies was done using Critical Appraisal Skills Programme (CASP) checklists. In total, 40 publications reflecting 25 different studies were included: nine studies addressed patients with psoriasis, 13 patients with AD, two studies included patients with HS and one study enrolled patients with psoriasis and AD, respectively. Twenty-two potential risk factors with underlying evidence were found in this review. These risk factors include mainly sociodemographic (such as age or gender) and clinical (such as disease severity or comorbidities) variables. Disease severity and comorbidities were the most often studied risk factors, while only a few studies evaluated psychosocial risk factors over time. Patients with chronic skin diseases are at high risk to develop a life-long negative impact from the disease. However, there is a lack of data that evaluates the psychosocial burden and its influence on the patients' life course over time. The risk factors found in this review help to identify patients at risk, to treat them adequately and, ultimately, to prevent CLCI. These results can be the basis to develop a highly needed tool to assess the risk for CLCI in the future.

Neonatal jaundice, phototherapy and childhood allergic diseases: An updated systematic review and meta-analysis

BACKGROUND

Neonatal jaundice and phototherapy have been associated with the development of allergic diseases. It has been suggested, however, that effect estimates of the associations might be smaller than expected. We sought to update the evidence of their associations including recently published large longitudinal studies.

METHODS

We sought published and unpublished observational studies through the major databases. We used a random-effect meta-analysis model weighted by the inverse variance estimate, the Quality in Prognosis Studies tool to assess the methodological quality for each study, and the Grading of Recommendations, Assessment, Development, and Evaluation approach to assess the certainty of evidence (COE).

RESULTS

Nineteen studies were enrolled in the qualitative syntheses, and fourteen studies were synthesized in the meta-analyses. Neonatal jaundice was associated with a higher risk of childhood-onset asthma (odds ratio [OR], 1.46; 95% confidence interval [95% CI], 1.39-1.53; COE, moderate), atopic dermatitis (AD; OR, 1.30; 95% CI, 1.07-1.57; COE, moderate), and allergic rhinitis (AR; OR, 3.01; 95% CI, 0.8810.30; COE, low). Neonatal phototherapy was also associated with a higher risk of childhood-onset asthma (OR, 1.24; 95% CI, 1.11-1.38; COE, moderate), AD (OR, 1.31; 95% CI, 1.24-1.39; COE, moderate), and AR (OR, 1.38; 95% CI, 0.93-2.04; COE, very low). There were no studies that reported effect estimates of the associations between childhood-onset food allergies and neonatal jaundice and phototherapy.

CONCLUSION

Neonatal jaundice and phototherapy were probably a prognostic factor of childhood-onset allergic diseases; however, the associations were likely to be smaller than previously estimated.

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.

Do Children With Constipation Have Increased Risk of Asthma? Real-World Data From a Nationwide Population-Based Cohort Study

Background: Asthma is one of the most burdensome childhood disorders. Growing evidence disclose intestinal dysbiosis may contribute to asthma via the gut-lung axis. Constipation can lead to alteration of the gut microbiota. The clinical impact of constipation on asthma has not been researched. Therefore, we aim to assess whether pediatric constipation influence the risk of developing asthma by a nationwide population-based cohort study. Methods: We analyzed 10,363 constipated patients and 10,363 individuals without constipation between 1999 and 2013 from Taiwan's National Health Insurance Research Database. Analysis of propensity score was utilized to match age, sex, comorbidities, and medications at a ratio of 1:1. In addition, multiple Cox regression analysis was performed to evaluate the adjusted hazard ratio of asthma. Furthermore, sensitivity tests and a stratified analysis were performed. Results: After adjustment for age, sex, comorbidities, and medications, constipated patients had a 2.36-fold greater risk of asthma compared to those without constipation [adjusted hazard ratio (aHR): 2.36, 95% C.I. 2.04-2.73, p < 0.001]. Furthermore, the severity of constipation is associated with an increased risk of asthma; the adjusted hazard ratio was 2.25, 2.85, and 3.44 within < 3, 3-12, and ≥12 times of laxatives prescription within 1 year, respectively (p < 0.001). Conclusion: Constipation was correlated with a significantly increased risk of asthma. Pediatricians should be aware of the possibility of asthma in constipated patients. Further research is warranted to investigate the possible pathological mechanisms of this association.

Reduced peanut sensitization with maternal peanut consumption and early peanut introduction while breastfeeding

New guidelines for peanut allergy prevention in high-risk infants recommend introducing peanut during infancy but do not address breastfeeding or maternal peanut consumption. We assessed the independent and combined association of these factors with peanut sensitization in the general population CHILD birth cohort (N = 2759 mother-child dyads). Mothers reported peanut consumption during pregnancy, timing of first infant peanut consumption, and length of breastfeeding duration. Child peanut sensitization was determined by skin prick testing at 1, 3, and 5 years. Overall, 69% of mothers regularly consumed peanuts and 36% of infants were fed peanut in the first year (20% while breastfeeding and 16% after breastfeeding cessation). Infants who were introduced to peanut early (before 1 year) after breastfeeding cessation had a 66% reduced risk of sensitization at 5 years compared to those who were not (1.9% vs. 5.8% sensitization; aOR 0.34, 95% CI 0.14-0.68). This risk was further reduced if mothers introduced peanut early while breastfeeding and regularly consumed peanut themselves (0.3% sensitization; aOR 0.07, 0.01-0.25). In longitudinal analyses, these associations were driven by a higher odds of outgrowing early sensitization and a lower odds of late-onset sensitization. There was no apparent benefit (or harm) from maternal peanut consumption without breastfeeding. Taken together, these results suggest the combination of maternal peanut consumption and breastfeeding at the time of peanut introduction during infancy may help to decrease the risk of peanut sensitization. Mechanistic and clinical intervention studies are needed to confirm and understand this "triple exposure" hypothesis.

Simultaneous Determination of 6 Antiallergic Components in Asarum sieboldii Using High-Performance Liquid Chromatography

Owing to the side effects of current drugs for treating atopic dermatitis (AD), a chronic disease in the skin, traditional herbal medicine is receiving much attention as an alternative treatment. Asarum sieboldii has traditionally been used to treat colds, fevers, headaches, coughs, neuralgia, chronic bronchitis, asthma, and allergies. In this study, 6 compounds (echinacoside, vanillic acid, kakuol, methyl eugenol, sesamin, and asarinin) in A. sieboldii were analyzed simultaneously using high-performance liquid chromatography (HPLC), and the proposed analytical method was validated. In addition, the inhibitory effects of the A. sieboldii extract and the 6 analyzed compounds on the expression of chemokine were evaluated in HaCaT cells. The HPLC method showed high linearity, with a correlation coefficient of ≥0.9999. The limits of detection for the 6 compounds ranged from 0.00 to 0.02 µg/mL, and the limits of quantification ranged from 0.01 to 0.05 µg/mL. The intraday and interday precisions were 0.15%-1.90%; the accuracy was 97.36%-103.23%, and the recoveries of the 6 compounds were 97.45%-103.93%. The content of each compound in A. sieboldii, as determined using the corresponding calibration curve, was in the range of 0.380-12.062 mg/g. This optimized simultaneous quantification method will be suitable for improving the quality control of A. sieboldii. Moreover, the 6 compounds in A. sieboldii showed an inhibitory effect on the production of chemokines, which suggests that A. sieboldii has an antiallergic effect.

Which Way Do We Go? Complex Interactions in Atopic Dermatitis Pathogenesis

Atopic dermatitis (AD) is a common, chronic, inflammatory skin condition characterized by recurrent and pruritic skin eruptions. Multiple factors contribute to the pathogenesis of AD, including skin barrier dysfunction, microbial dysbiosis, and immune dysregulation. Interactions among these factors form a complex, multidirectional network that can reinforce atopic skin disease but can also be ameliorated by targeted therapies. This review summarizes the complex interactions among contributing factors in AD and the implications on disease development and therapeutic interventions.

Remote allergen exposure elicits eosinophil infiltration into allergen nonexposed mucosal organs and primes for allergic inflammation

The natural history of allergic diseases suggests bidirectional and progressive relationships between allergic disorders of the skin, lung, and gut indicative of mucosal organ crosstalk. However, impacts of local allergic inflammation on the cellular landscape of remote mucosal organs along the skin:lung:gut axis are not yet known. Eosinophils are tissue-dwelling innate immune leukocytes associated with allergic diseases. Emerging data suggest heterogeneous phenotypes of tissue-dwelling eosinophils contribute to multifaceted roles that favor homeostasis or disease. This study investigated the impact of acute local allergen exposure on the frequency and phenotype of tissue eosinophils within remote mucosal organs. Our findings demonstrate allergen challenge to skin, lung, or gut elicited not only local eosinophilic inflammation, but also increased the number and frequency of eosinophils within remote, allergen nonexposed lung, and intestine. Remote allergen-elicited lung eosinophils exhibited an inflammatory phenotype and their presence associated with enhanced susceptibility to airway inflammation induced upon subsequent inhalation of a different allergen. These data demonstrate, for the first time, a direct effect of acute allergic inflammation on the phenotype and frequency of tissue eosinophils within antigen nonexposed remote mucosal tissues associated with remote organ priming for allergic inflammation.

Research Progress in Atopic March

The incidence of allergic diseases continues to rise. Cross-sectional and longitudinal studies have indicated that allergic diseases occur in a time-based order: from atopic dermatitis and food allergy in infancy to gradual development into allergic asthma and allergic rhinitis in childhood. This phenomenon is defined as the “atopic march”. Some scholars have suggested that the atopic march does not progress completely in a temporal pattern with genetic and environmental factors. Also, the mechanisms underlying the atopic march are incompletely understood. Nevertheless, the concept of the atopic march provides a new perspective for the mechanistic research, prediction, prevention, and treatment of atopic diseases. Here, we review the epidemiology, related diseases, mechanistic studies, and treatment strategies for the atopic march.

TSLP as druggable target - a silver-lining for atopic diseases?

Atopic diseases refer to common allergic inflammatory diseases such as atopic dermatitis (AD), allergic rhinitis (AR), and allergic asthma (AA). AD often develops in early childhood and may herald the onset of other allergic disorders such as food allergy (FA), AR, and AA. This progression of the disease is also known as the atopic march, and it goes hand in hand with a significantly impaired quality of life as well as a significant economic burden. Atopic diseases usually are considered as T helper type 2 (Th2) cell-mediated inflammatory diseases. Thymic stromal lymphopoietin (TSLP), an epithelium-derived pro-inflammatory cytokine, activates distinct immune and non-immune cells. It has been shown to be a master regulator of type 2 immune responses and atopic diseases. In experimental settings, the inhibition or knockout of TSLP signaling has shown great therapeutic potential. This, in conjunction with the increasing knowledge about the central role of TSLP in the pathogenesis of atopic diseases, has sparked an interest in TSLP as a druggable target. In this review, we will discuss the autocrine and paracrine effects of TSLP, how it regulates the tissue microenvironment and drives atopic diseases, which provide the rationale for the increasing interest in TSLP as a druggable target.

Histoire naturelle de la dermatite atopique

Atopic dermatitis (AD) is a common frequent chronic inflammatory skin disease which begins frequently in infancy. The clinical expression of AD is a recurrent eczema on a dry skin. AD is a multifactorial disease characterized by two linked abnormalities: a skin barrier defect and a cellular inflammation, with type-2 main components. However, the pathophysiology of AD is not as simple as this description looks like. In this review, we will present a synthesis of current knowledge on natural history of AD and the involved factors, in order to clarify AD care. The evolution of AD is associated with many atopic comorbidities, following the "atopic march" scheme: IgE-mediated food allergy, allergic asthma and rhinitis occurring classically after AD. In fact, this is rarely the case, but the atopic march seems to be associated with AD severity. AD has also many neuropsychological complications which are essential to be detected. Other factors could influence the natural history of AD: genetic mutations on different genes (proteins of skin barrier, innate and adaptive immunity pathways), skin dysbiosis with colonization by Staphylococcus aureus, sensitization against environmental proteins. AD treatment is based on the restauration of the skin barrier using emollients and on anti-inflammatory drugs (notably topical corticosteroids) during the inflammatory flares. It is not recommended to treat the skin colonization by S. aureus, excepted in case of skin infection. The probiotics have no efficiency as curative treatment of AD, but could have an interest for the primary prevention, especially in at-risk populations. © 2019 Elsevier Masson SAS. All rights reserved.

Early origins of allergy and asthma (ARIES): study protocol for a prospective prenatal birth cohort in Chile

Background

Growing evidence shows that atopic dermatitis (AD), food allergy (FA), allergic rhinitis, and asthma are largely determined during the first 1000 days (time elapsed from conception to the 2nd birthday). The ARIES birth cohort aims to determine prenatal and perinatal conditions, as well as genetic and epigenetic factors, that participate in the early setting of immune responses, and the role of these in the later determination of the risk of allergic diseases and asthma in the offspring.

Methods

We have designed a birth cohort of 250 families with prenatal recruitment (~ 14 weeks). We will genotype relevant allergy/asthma-associated variants in trios and will perform immunophenotyping and evaluation of allergy biomarkers in cord blood. At 1 and 2 years of age we will assess if infants have developed allergic sensitization, AD, FA, as well as biomarkers of asthma including the asthma predictive index. We will also evaluate how maternal conditions modify immune programming through epigenetic modifications and will then depict newborn epigenetic cues of allergy/asthma risk. Next, we will assess composition/diversity of maternal gut, placenta, breastmilk and infant gut microbiome and their association with immunophenotype and biomarkers at birth, and clinical outcomes at age 1 and 2. Finally, we plan to assess how environmental exposures (perinatal outdoor and indoor pollution, allergens and endotoxin) affect the incidence of allergic sensitization, AD, FA, and risk of asthma.

Discussion

The in-depth study of the ARIES birth cohort shall provide crucial information to understand the rising incidence of allergies and asthma in developing countries, and hopefully provide cues on how to prevent and treat these diseases.

Trial registration

clinicaltrials.gov NCT04186949, retrospectively registered on December 5, 2019.

Exposure to diisononyl phthalate promotes atopic march by activating of NF-κB and p38 MAPK

What factors and underlying mechanisms influence the occurrence of the atopic march remain unclear. Recent studies suggest that exposure to diisononyl phthalate (DINP) might be associated with the occurrence of atopic dermatitis (AD) and asthma. However, little is known about the role of DINP exposure in the atopic march. In this study, we investigated the effect of DINP exposure on the progression from AD to asthma, and explored the potential mechanisms. We built an atopic march mouse model from AD to asthma, by exposure to DINP and sensitization with OVA. Pyrrolidine dithiocarbamate and SB203580 were used to block NF-κB and p38 MAPK respectively, to explore the possible molecular mechanisms. The data showed that DINP aggravated airway remodeling and airway hyperresponsiveness (AhR) in the progression from AD to asthma, induced a sharp increase in IL-33, IgE, Th2 and Th17 cytokines, and resulted in an increase in the expression of thymic stromal lymphopoietin (TSLP) and in the number of inflammatory cells. Blocking NF-κB inhibited AD-like lesions, and the production of IL-33 and TSLP in the progression of AD, while alleviating airway remodeling, AhR, and the expression of Th2 and Th17 cytokines in both the progression of AD and the asthmatic phenotype. Blocking p38 MAPK in the progression of asthma, inhibited airway remodeling, AhR, and the expression of Th2 and Th17 cytokines. The results demonstrated that exposure to DINP enhanced the immune response to memory CD4⁺ T helper cells through the NF-κB and p38 MAPK signaling pathways, leading to an aggravation of the atopic march.

Gut microbiota of children with atopic dermatitis: Controlled study in the metropolitan region of São Paulo, Brazil

BACKGROUND

It is possible that imbalances in the composition of the gut microbiota or the relationship of the microbiota with the host may be implicated in the origin of allergy. Therefore, we studied the intestinal microbiota of children with atopic dermatitis (AD).

METHODS

Cross-sectional study with 81 children aged 5-11; 23 with AD and 58 controls. Surveys were conducted to obtain demographic, socioeconomic and neonatal data. Diagnosis of AD was made based on the International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire. Eubacteria, Bacteroidetes, Firmicutes, B. fragilis, E. coli, Lactobacillus spp., S. aureus, E. faecalis, Salmonella spp., M. smithii, Bifidobacterium spp., C. difficile and C. perfringens were quantified using real-time PCR.

RESULTS

The analysis showed an association between presence of C. difficile (OR: 5.88; 95 % CI: 1.24; 27.98), greater abundance of bifidobacteria (OR: 11.09; 95 % CI: 2.14; 57.39) and a lower abundance of lactobacilli (OR: 0.07; 95 % CI: 0.01; 0.51) in the gut microbiota of children with AD. Counts of Eubacteria (0,05×10³ and 8.49×10³), B. fragilis (0.72×10⁹ and 4.5×10⁹), Lactobacillus spp. (0.02×10⁸ and 0.38×10⁸), E. coli (0.13×10⁹ and 1.52×10⁹) and M. smithii (0.02×10⁸ and 0.31×10⁸) were lower in children with AD (P<0.05).

CONCLUSIONS

This study confirmed that children living in the metropolitan area of São Paulo (Brazil) with AD have a different microbiota pattern with higher prevalence of C. difficile, lower abundance of Lactobacillus and greater abundance of bifidobacteria, regardless of socioeconomic status.

Study of atopic multimorbidity in subjects with rhinitis using multiplex allergen component analysis

Background

Rhinitis is a common problem within the population. Many subjects with rhinitis also have atopic multimorbidity, such as asthma and eczema. The purpose of this investigation was to compare subjects with only rhinitis to those that have rhinitis, asthma and/or eczema in relation to immunoglobulin E (IgE) sensitization, inflammatory markers, family history, lung function and body mass index (BMI).

Methods

A total of 216 adult subjects with rhinitis from the European Community Respiratory Health Survey II were investigated with multiplex component allergen analysis (103 allergen components), total IgE, C-reactive protein, eosinophilic cationic protein, fractional exhaled nitric oxide and spirometry. Rhinitis, eczema, asthma and parental allergy were questionnaire-assessed.

Results

Of the 216 participants with rhinitis, 89 also had asthma and/or eczema. Participants with rhinitis that also had asthma or eczema were more likely to be IgE-sensitized (3.44, odds ratio, OR: 95% CI 1.62–7.30, adjusted for sex, age, mother’s allergy, total IgE and forced expiratory volume (FEV₁)). The number of IgE-positive components was independently associated with atopic multimorbidity (1.11, OR: 95% Cl 1.01–1.21) adjusted for sex, age, mother’s allergy, total IgE and FEV₁. When analysing different types of sensitization, the strongest association with atopic multimorbidity was found in participants that were IgE-sensitized both to perennial and seasonal allergens (4.50, OR: 95% CI 1.61–12.5). Maternal allergy (2.75, OR: 95% CI 1.15–4.46), high total IgE (2.38, OR: 95% CI 1.21–4.67) and lower FEV₁ (0.73, OR: 95% CI 0.58–0.93) were also independently associated with atopic multimorbidity, while no association was found with any of the other inflammatory markers.

Conclusion

IgE polysensitization, to perennial and seasonal allergens, and levels of total IgE seem to be the main determinants of atopic multimorbidity in subjects with rhinitis. This indicates that disease-modifying treatment that targets IgE sensitization may be of value when decreasing the risk of developing atopic multimorbidity.