Atopic dermatitis in a high-risk cohort: natural history, associated allergic outcomes, and risk factors

Real-world efficacy and safety of dupilumab for paediatric atopic dermatitis: a multicentre retrospective study

BACKGROUND

Real-world data regarding the use of dupilumab in children with atopic dermatitis (AD) are limited.

OBJECTIVES

To evaluate the real-world efficacy of dupilumab in children with moderate-to-severe AD over an extended follow-up period.

METHODS

This was a retrospective study of patients (≤ 18 years) with moderate-to-severe AD treated with dupilumab in four Israeli tertiary centres. Efficacy and safety were assessed using descriptive statistics.

RESULTS

In total, 230 patients were included in the analysis [age 9.9 years (SD 4.3), male/female 1 : 1 ratio)]. Of them, 59.6% (137/230) had ≥ 1 atopic comorbidity. The follow-up duration ranged from 2 to 248 weeks, with a median of 52 weeks (interquartile range 24-96). Within 12 weeks of treatment, 41.7% (68/163) of patients had reached Investigator Global Assessment 0-1. The mean body surface area was reduced from 58.0% (SD 20.5%) at baseline to 27.8% (SD 20.2%) at 12 weeks. The average Pruritus Numeric Rating Scale score was reduced from 7.9 (SD 2.2) at baseline to 2.3 (SD 2.8) at 12 weeks. Adverse events, in 210 patients, included conjunctivitis in 34 patients (16.2%), injection-site reactions in 11 patients (5.2%) and dupilumab-associated head and neck dermatitis in 6 patients (2.9%). Overall, 26 of 210 patients (12.3%) discontinued the treatment: 9 of the 26 patients (35%) because of adverse events and 15 patients (58%) because of inadequate efficacy. The overall probability of dupilumab survival at 52 weeks was 94.0%.

CONCLUSIONS

Real-world data presented here for 230 paediatric and adolescents with moderate-to-severe AD reinforce dupilumab's efficacy and safety and highlight dupilumab's high survival rate after 1 year of treatment in the paediatric population.

[Consensus for the treatment of atopic dermatitis in primary care: resolving myths and legends based on evidence]

Atopic dermatitis (AD) is a disease that significantly impacts the quality of life of patients. Although there are multiple evidence-based guidelines, they are usually aimed at providing recommendations to AD specialists rather than primary care physicians (PCPs). The aim of this study was to construct a consensus document for PCPs, with the aim of presenting evidence-based recommendations that allow general practitioners, family physicians, pediatricians, internists and emergency physicians to provide appropriate care to AD patients, facilitating their diagnosis, management, and avoiding delays that can deteriorate patients' f quality of life. As a central source of information, we used the recommendations of different international AD guidelines. Delegates from distinct medical societies identify barriers to care and possible solutions for the application of recommendations in primary care. Subsequently, a second evaluation for physicians from different Latin American countries was carried out. The main doubts and barriers that PCPs face in applying the recommendations proposed by the guidelines were identified across different areas, diagnostic criteria, non-pharmacological therapies, pharmacological therapies, management in special conditions and guidelines for referral to a specialist. Consensus solutions were proposed for each identified issue. In conclusion, this consensus contains recommendations regarding the management and treatment of AD in children and adults, which clarify doubts and provide tools to primary care physicians to offer effective treatment for patients and their families.

Mechanisms for initiation of food allergy by skin pre-disposed to atopic dermatitis

Food allergy can be life-threatening and often develops early in life. In infants and children, loss-of-function mutations in skin barrier genes associate with food allergy. In a mouse model with skin barrier mutations (Flakey Tail, FT+/- mice), topical epicutaneous sensitization to a food allergen peanut extract (PNE), an environmental allergen Alternaria alternata (Alt) and a detergent induce food allergy and then an oral PNE-challenge induces anaphylaxis. Exposures to these allergens and detergents can occur for infants and children in a household setting. From the clinical and preclinical studies of neonates and children with skin barrier mutations, early oral exposure to allergenic foods before skin sensitization may induce tolerance to food allergens and thus protect against development of food allergy. In the FT+/- mice, oral food allergen prior to skin sensitization induce tolerance to food allergens. However, when the skin of FT+/- pups are exposed to a ubiquitous environmental allergen at the time of oral consumption of food allergens, this blocks the induction of tolerance to the food allergen and the mice can then be skin sensitized with the food allergen. The development of food allergy in neonatal FT+/- mice is mediated by altered skin responses to allergens with increases in skin expression of interleukin 33, oncostatin M and amphiregulin. The development of neonate food allergy is enhanced when born to an allergic mother, but it is inhibited by maternal supplementation with α-tocopherol. Moreover, preclinical studies suggest that food allergen skin sensitization can occur before manifestation of clinical features of atopic dermatitis. Thus, these parameters may impact design of clinical studies for food allergy, when stratifying individuals by loss of skin barrier function or maternal atopy before offspring development of atopic dermatitis.

Atopic diseases-Diagnostics, mechanisms, and exposures

Epidemiological data suggest that atopic diseases begin in early life and that most cases present clinically during early childhood. The diseases are highly prevalent and increase as communities adopt western lifestyles. Disentangling the pathophysiological mechanisms leading to disease debut is necessary to identify beneficial/harmful exposures so that successful prevention and treatment can be generated. The objective of this review is to explore the definition of atopy and mechanisms of atopic diseases, and to investigate the importance of environmental factors in early life, prior to disease development. First, the distribution of sIgE levels in children is investigated, as this is one of the main criteria for the definition of atopy. Thereafter, it is explored how studies of parental atopic status, sensitization patterns, and early debut and severity of atopic dermatitis have substantiated the theory of an early-life window of opportunity for intervention that precedes the development of atopic diseases in childhood. Then, it is examined whether early-life exposures such as breastfeeding, dogs, cats, and house dust mites in the home perinatally constitute important influencers in this crucial time of life. Finally, it is discussed how these findings could be validated in randomized controlled trials, which might prepare the ground for improved diagnostics and prevention strategies to mitigate the current atopic pandemic.

Patterns of Common Dermatological Conditions among Children and Adolescents in Pakistan

Background and Objectives: Dermatological disorders are highly prevalent among children in Pakistan. The present cross-sectional study aims to identify the spectrum of dermatological conditions among children and adolescents in Pakistan. Materials and Methods: A total of 582 patients (50.9% males; 49.1% females) were included in the study based on their age (5.7 ± 4.1 years), dermatological condition, and epidemiology. The youngest patient was aged ten days, whereas the eldest was seventeen. Age criteria were further stratified into three categories: infants and toddlers (≤5 years), children (≥5 to <12 years), and adolescents (≥12 to <18 years). Amongst them, the majority was from Punjab (81.6%), while the other regions included were Azad Jammu and Kashmir (14.4%), Islamabad (3.3%), and Khyber Pakhtunkhwa (0.7%). Results: Scabies was the highest reported skin condition with 281 (45.55%) patients, followed by 114 (19.6%) with eczema, 60 (10.3%) with dermatitis, 33 (5.7%) with tinea capitis, 17 (2.9%) with tinea corporis, 16 (2.7%) with impetigo, and 15 (2.6%) with folliculitis. Other conditions include urticaria, burns, infections, pediculosis, tinea inguinalis, tinea faciei, nappy rashes, alopecia, warts, tinea incognito, tinea cruris, and acne vulgaris. The chi-squared test showed a high prevalence of tinea corporis and acne among adolescents (12-17 years), whereas eczema, dermatitis, and impetigo were more prevalent among infants and toddlers. Conclusions: Pets or livestock and poor hygiene were found to be highly reported risk factors for many dermatological conditions like scabies and fungal infections. Dermatological conditions are common in younger individuals, but unfortunately, many children do not receive the desired medical assistance.

Assessing anatomical distribution of atopic dermatitis identifies a cluster of patients with late onset and low risk of asthma and allergy: An observational study

Background and Aims

A better understanding of distinct subgroups in atopic dermatitis (AD) is warranted. The aim was to identify and determine characteristics of clusters based on anatomical location of AD.

Methods

In this 8-week, observational, decentralized study, patients with AD completed a baseline questionnaire about anatomical location and severity of AD, and a principal component analysis (PCA) was applied to identify clusters. The Patient-Oriented Eczema Measure (POEM) was completed weekly and photographs of affected body areas were captured by the participants' own smartphones. From the weekly photographs, the AD severity was evaluated using the intensity part of the SCORing Atopic Dermatitis.

Results

Fifty-five participants were recruited, of which 53 completed the baseline questionnaire with a mean POEM of 14.5 (SD: 5.6). The PCA analysis revealed three clusters, with AD predominantly on the shins, knees, and genitals (Cluster 1), with involvement of the upper body (Cluster 2), and with AD on the hands and feet (Cluster 3). Cluster 1 had a lower mean POEM score (11.12, SD: 5.3) compared with Clusters 2 (12.64, SD: 4.5) and 3 (15.98, SD: 4.7), respectively (p = 0.007). Further, Cluster 1 had the highest age of AD onset (mean 9.5 vs. 2.5 and 4.7 years, p = 0.02) and the lowest proportion of asthma/allergy (47% vs. 82% and 90%, p = 0.01).

Conclusion

Three clusters of patients with AD based on affected body areas were identified. The cluster with involvement of legs and genitals was characterized by the oldest age of AD onset and the lowest prevalence of asthma/allergy.

The hen and the egg question in atopic dermatitis: allergy or eczema comes first

Atopic dermatitis (AD) as a chronic inflammatory systemic condition is far more than skin deep. Co-morbidities such as asthma and allergic rhinitis as well as the psychological impact influence seriously the quality of life of the patients. Recent studies have shown that only 10% of atopic patients undergo full manifestation of the atopic march, while 40% demonstrate concomitant food allergy. Exposure to food allergens in the environment causes sensitization and food allergy through the disruption of the skin barrier, as in AD. Food allergy and AD are closely related. While not all AD patients have a food allergy, 20-40% of children with moderate to severe AD will have an IgE-mediated food allergy. It is known that they may coexist but it is unclear if food allergy worsens the course of AD. Experimental, clinical, and epidemiological studies have provided evidence of the primary role of an epidermal barrier defect in the development of sensitization to environmental allergens and that this process occurs in the damaged skin barrier rather than the gastrointestinal or respiratory tract. There is strong evidence for a connection between early AD onset and the development of other allergic diseases later in life.

The efficacy and safety of lebrikizumab monotherapy for the management of moderate-to-severe atopic dermatitis: A systematic review and meta-analysis

Background

Atopic dermatitis (AD) is a chronically relapsing disease. Few biologics are approved for moderate-to-severe AD, and novel interventions are emerging. We aimed to evaluate the safety and efficacy of lebrikizumab, an IL-13 immunomodulator, as monotherapy vs. placebo in treating moderate-to-severe AD.

Methods

Cochrane Central Register of Controlled Trials (CENTRAL), Medline, Embase, and ClinicalTrials.gov registry (CT.gov) databases were systematically searched. We evaluated lebrikizumab vs. placebo and measured efficacy using Eczema Area and Severity Index (EASI), Body Surface Area (BSA), and Investigator's Global Assessment (IGA) change from baseline to week 16. Safety was evaluated by the incidence of serious adverse events (SAEs), non-serious adverse events (NSAEs), and mortality. The risk of bias was investigated using the Revised Cochrane risk of bias tool.

Results

Three RCTs (n = 1,149) included 543 (47.25%) men vs. 606 (52.75%) women. Meta-analysis showed statistically significant improvement in EASI, IGA, and BSA. EASI75 at week 16 for all regimens was (RR = 2.62, 95% CI [2.06, 3.34], p < 0.00001) with the first regimen (500 mg loading dose then 200 mg every 2 weeks) showing the most significant improvement (RR = 3.02, 95% CI [2.39, 3.82], p < 0.00001). The pooled analysis of safety outcomes concluded that lebrikizumab did not correlate significantly with the incidence of SAEs, NSAEs, and mortality.

Conclusion

Overall, lebrikizumab showed a significant improvement in all efficacy outcomes. Additionally, it did not contribute to any significant incidence of SAEs, NSAEs, or mortality. The risk of bias in included RCTs was minor except in the randomization domain. Grading of Recommendations Assessment, Development, and Evaluation (GRADE) assessment of the outcomes ranged from low to high, but predominantly high certainty of evidence.

Systematic review registration

https://www.crd.york.ac.uk/prospero/, identifier CRD42022362438.

Atopic Dermatitis With Coexisting Food Allergy in Early Life Is Associated With Childhood Asthma

PURPOSE

Atopic dermatitis (AD) and food allergy (FA) are associated with respiratory comorbidities, in the concept of 'atopic march.' However, children with AD and a coexisting FA have various disease courses, and the mechanism of atopic march remains unclear. In this study, we investigated whether the phenotype of AD with coexisting FA in early life affected asthma or allergic rhinitis (AR) in school children.

METHODS

A total of 1,579 children from the Panel Study on Korean Children (PSKC) cohort were followed-up in 2013. The participants diagnosed with AD in this cohort were classified by the age of AD onset and persistence as well as FA history. We compared the presence of comorbidities-asthma and rhinitis-among different AD phenotypes.

RESULTS

Asthma and AR with current symptoms within 12 months at age 6-8 years were associated with early-onset persistent AD phenotype, regardless of coexisting FA. AD with FA conferred a higher risk of recent wheezing at 8 years of age than AD without FA (adjusted odds ratio, 8.09; 95% confidence interval, 2.54-25.76). Children with early-onset persistent AD with FA manifested a distinctive trajectory with a higher prevalence of wheezing and AR at age 5-8 years than those without AD.

CONCLUSIONS

AD with FA in early life is strongly associated with asthma and AR in school children, and the early-onset persistent AD with FA had a strong additive effect on the risk of asthma at school age. Classifying AD phenotypes regarding FA in early life will help predict and prevent asthma and AR in school children.

Functional Recognition Theory and Type 2 Immunity: Insights and Uncertainties

Type 2 immunity plays an important role in host defense against helminths and toxins while driving allergic diseases. Despite progress in understanding the biology of type 2 immunity, the fundamental mechanisms regulating the type 2 immune module remain unclear. In contrast with structural recognition used by pattern recognition receptors, type 2 immunogens are sensed through their functional properties. Functional recognition theory has arisen as the paradigm for the initiation of type 2 immunity. However, the vast array of structurally unrelated type 2 immunogens makes it challenging to advance our understanding of type 2 immunity. In this article, we review functional recognition theory and organize type 2 immunogens into distinct classes based on how they fit into the concept of functional recognition. Lastly, we discuss areas of uncertainty in functional recognition theory with the goal of providing a framework to further define the logic of type 2 immunity in host protection and immunopathology.

Probiotics for the prevention of atopic dermatitis in infants from different geographic regions: a systematic review and meta-analysis

BackgroundAtopic dermatitis (AD) is a common skin disease during infancy, but the preventive effect of probiotics on AD remains unclear.AimTo evaluate the efficacy of probiotic supplementation for the prevention of AD in infants.MethodsPubMed, Cochrane Library, and Embase databases were reviewed for relevant randomized controlled trials (RCTs). Two authors independently extracted the data. The primary endpoint was the risk of AD in infants. Risk ratio (RR) and 95% confidence interval (CI) were calculated.ResultsA total of 20 related articles including 22 studies were included. A significant reduction in AD risk was revealed for the probiotic group compared to the control group (RR 0.76; 95% CI 0.67-0.87). Subgroup analyses by participant receiving intervention revealed that not only probiotics given to mother (RR 0.70; 95% CI 0.57-0.85) or given to mother and infant (RR 0.76; 95% CI 0.61-0.95) were effective in preventing AD in infants, and probiotics given to infants alone (RR 0.76; 95% CI 0.60-0.96) still effectively decreased the risk of AD.ConclusionProbiotic supplementation reduced the risk of developing AD in infants. Furthermore, probiotic supplementation given to mother or to mother and infant could effectively prevent AD in infants.

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.

Age-specific associations of early daycare, older siblings, severe airway infection, and preterm birth with subsequent atopic diseases

BACKGROUND

The effects of infection and developmental adaptations in infancy on the prevalence of subsequent atopy-related diseases at different ages during childhood are not fully determined. This study aims to examine the similarities and differences in the age-specific association of asthma, allergic rhinitis/conjunctivitis, and atopic dermatitis with early-life infection-related factors (i.e., daycare, older siblings, and severe airway infection) and developmental adaptations (i.e., preterm birth and rapid weight gain) in children.

METHODS

In this longitudinal cohort study (n = 47,015), children were followed from 0.5 to 11 years. The potential risks and protective factors, including daycare attendance at 0.5 years, existence of older siblings, history of hospitalization due to cold/bronchitis/bronchiolitis/pneumonia during 0.5-1.5 years, preterm birth, and rapid weight gain in the first 2.5 years, were assessed using multivariable logistic regression with adjustments for potential confounders.

RESULTS

A protective association was observed between early-life daycare attendance and asthma at 5.5-9 years, which disappeared after 10 years. A protective association was also noted throughout childhood between early daycare attendance and older siblings with allergic rhinitis/conjunctivitis. However, the association between early daycare and atopic dermatitis was found to be risky during childhood. In contrast, the early-life history of hospitalization owing to cold/bronchitis/bronchiolitis/pneumonia was identified to be a risk factor for developing both asthma and allergic rhinitis/conjunctivitis. Preterm birth was a significant risk factor for childhood asthma.

CONCLUSION

Different age-specific patterns were demonstrated in the relationship between early daycare, severe airway infection, preterm birth, and atopy-related diseases in childhood.

Clinical Characteristics of Atopic Dermatitis in Korean School-Aged Children and Adolescents According to Onset Age and Severity

BACKGROUND

Atopic dermatitis (AD) is a heterogeneous disease with different age of onset, disease course, clinical symptoms, severity, and risk of comorbidity. The characteristics of children with AD also vary by age or country. However, little is known about the clinical characteristics of AD in Korean school-aged children and adolescents. Furthermore, there are few studies on phenotypic differences according to onset age. This study aimed to explore the clinical characteristics and phenotypes according to onset age and severity of AD in children and adolescents in Korea.

METHODS

AD patients aged 6-18 years who presented to 18 hospitals nationwide were surveyed. The patients were examined for disease severity by pediatric allergy specialists, and data on history of other allergic diseases, familial allergy history, onset age, trigger factors, lesion sites, treatment history and quality of life were collected. The results of the patient's allergy test were also analyzed. The patients were classified into infancy-onset (< 2 years of age), preschool-onset (2-5 years of age), and childhood-onset (≥ 6 years of age) groups. Study population was analyzed for clinical features according to onset-age groups and severity groups.

RESULTS

A total of 258 patients with a mean age of 10.62 ± 3.18 years were included in the study. Infancy-onset group accounted for about 60% of all patients and presented significantly more other allergic diseases, such as allergic rhinitis and asthma (P = 0.002 and P = 0.001, respectively). Food allergy symptoms and diagnoses were highly relevant to both earlier onset and more severe group. Inhalant allergen sensitization was significantly associated with both infancy-onset group and severe group (P = 0.012 and P = 0.024, respectively). A family history of food allergies was significantly associated with infancy-onset group (P = 0.036). Severe group was significantly associated with a family history of AD, especially a paternal history of AD (P = 0.048 and P = 0.004, respectively). Facial (periorbital, ear, and cheek) lesions, periauricular fissures, hand/foot eczema, and xerosis were associated with infancy-onset group. The earlier the onset of AD, the poorer the quality of life (P = 0.038). Systemic immunosuppressants were used in only 9.6% of the patients in the severe group.

CONCLUSION

This study analyzed the clinical features of AD in Korean children and adolescents through a multicenter nationwide study and demonstrated the phenotypic differences according to onset age and severity. Considering the findings that the early-onset group is more severe and accompanied by more systemic allergic diseases, early management should be emphasized in young children and infants.

Mechanisms for Alternaria alternata Function in the Skin During Induction of Peanut Allergy in Neonatal Mice With Skin Barrier Mutations

Neonatal mice with heterozygous mutations in genes encoding the skin barrier proteins filaggrin and mattrin (flaky tail mice [FT^+/-]) exhibit oral peanut-induced anaphylaxis after skin sensitization. As we have previously reported, sensitization in this model is achieved via skin co- exposure to the environmental allergen Alternaria alternata (Alt), peanut extract (PNE), and detergent. However, the function of Alt in initiation of peanut allergy in this model is little understood. The purpose of this study was to investigate candidate cytokines induced by Alt in the skin and determine the role of these cytokines in the development of food allergy, namely oncostatin M (Osm), amphiregulin (Areg), and IL-33. RT-qPCR analyses demonstrated that skin of FT^+/- neonates expressed Il33 and Osm following Alt or Alt/PNE but not PNE exposure. By contrast, expression of Areg was induced by either Alt, PNE, or Alt/PNE sensitization in FT^+/- neonates. In scRNAseq analyses, Osm, Areg, and Il33 were expressed by several cell types, including a keratinocyte cluster that was expanded in the skin of Alt/PNE-exposed FT^+/- pups as compared to Alt/PNE-exposed WT pups. Areg and OSM were required for oral PNE-induced anaphylaxis since anaphylaxis was inhibited by administration of neutralizing anti-Areg or anti-OSM antibodies prior to each skin sensitization with Alt/PNE. It was then determined if intradermal injection of recombinant IL33 (rIL33), rAreg, or rOSM in the skin could substitute for Alt during skin sensitization to PNE. PNE skin sensitization with intradermal rIL33 was sufficient for oral PNE-induced anaphylaxis, whereas skin sensitization with intradermal rAreg or rOSM during skin exposure to PNE was not sufficient for anaphylaxis to oral PNE challenge. Based on these studies a pathway for IL33, Areg and OSM in Alt/PNE sensitized FT^+/- skin was defined for IgE induction and anaphylaxis. Alt stimulated two pathways, an IL33 pathway and a pathway involving OSM and Areg. These two pathways acted in concert with PNE to induce food allergy in pups with skin barrier mutations.

Atopic Dermatitis-Beyond the Skin

Atopic dermatitis is a chronic inflammatory disease that can arise during the first months of life or at maturity and have a significant negative impact on the quality of life. The main pathogenic mechanism is the breakdown of cutaneous barrier integrity, which is associated with systemic inflammatory immunologic disorders. Atopic dermatitis involves numerous immunologic, allergic, respiratory, and ophthalmologic comorbidities that develop through similar intricate pathogenic phenomena. The atopic march represents the evolution in time of various allergic diseases, of which food allergies often cause the first manifestations of atopy, even from a very young age. Chronic inflammation translated through specific markers, next to increased immunoglobulin E (IgE) serum levels and heterogenous clinical manifestations, argue for the inclusion of atopic dermatitis in the systemic disease category.

Phenotypes of atopic dermatitis and the risk for subsequent asthma: a systematic review and meta-analysis

BACKGROUND

Various atopic dermatitis (AD) phenotypes showed an enormously heterogenic risk for subsequent asthma development.

OBJECTIVE

We aimed to investigate the association between AD phenotypes and the risk for progression to asthma.

METHODS

We searched PubMed, Embase, and Web of Science databases for relevant publications. Pooled relative risks (RR) with 95% confidence intervals (CI) were calculated using the CMA-3.0 software. This study has been registered with PROSPERO (CRD42019129273).

RESULTS

We analyzed 39 publications with 458,810 participants. The RR for asthma in AD was 2.16 (95% CI, 1.88-2.48). The risk in persistent AD (RR, 3.36; 95% CI, 2.83-3.99) was higher than in transient AD (RR, 1.52; 95% CI, 1.34-1.73), and in severe AD (RR, 2.40; 95% CI, 1.96-2.94) was higher than mild (RR, 1.82; 95% CI, 1.03-3.23) or moderate (RR, 1.51; 95% CI, 1.30-1.75) AD. The risk for asthma in early-onset AD was slightly higher than in late-onset AD and in boys higher than girls.

LIMITATIONS

The AD and asthma definitions differed across the included studies.

CONCLUSION

Patients with persistent or severe AD were at a higher risk for developing asthma. These findings further elucidate the atopic march and identify target populations for asthma prevention.

Adherence to Guideline-Oriented Preventive Measures in Patients with Atopic Dermatitis in Germany

BACKGROUND

Atopic dermatitis (AD) is a chronic inflammatory skin disease that is often associated with comorbidities and quality of life losses. The implementation of evidence-based preventive measures strengthens patient participation and offers the potential to improve quality of care for AD.

OBJECTIVES

To assess adherence to guideline-oriented preventive measures in adult patients with AD in dermatological routine care in Germany.

METHODS

The self-responsible application of preventive measures, clinical features, pruritus, disease severity, and duration of disease as well as skin disease-related quality of life were assessed in two independent cross-sectional studies in 2010 and 2017-2019.

RESULTS

Between 2017 and 2019, 706 patients (55.8% female, mean age 41 years) were recruited in a comparable way to the survey in 2010 with 1,678 patients (60.5% female, mean age 38 years). Regular skin care was applied by 99.5% (2010: 94.9%), 90.9% avoided skin irritants (2010: 84.6%), and 80.2% (2010: 61.6%) did not smoke at home. Relaxation techniques were applied by 44.4% (2010: 29.9%). Advice on self-help measures was taken by 36.4% (2010: 27.1%) and 29.2% (2010: 15.4%) attended AD patient education courses. All six preventive measures categorized as obligatory were performed by 13.9% of the patients (2010: 6.7%). Predictors for the number of obligatory preventive measures applied were a high level of education, a longer disease duration, and a lower quality of life.

CONCLUSIONS

Although the self-reported use of evidence-based preventive measures in the 2017-2019 study appears to be more frequent than in 2010, important measures are still insufficiently established. Hence, more implementation, including education, is needed to increase the use of guideline-oriented preventive measures.

The Effectiveness of Probiotic Lactobacillus rhamnosus and Lactobacillus casei Strains in Children with Atopic Dermatitis and Cow's Milk Protein Allergy: A Multicenter, Randomized, Double Blind, Placebo Controlled Study

Probiotics seem to have promising effects in the prevention and treatment of allergic conditions including atopic dermatitis (AD) and food allergy. The purpose of this multicenter randomized placebo-controlled trial was to evaluate the effectiveness of a probiotic preparation comprising Lactobacillus rhamnosus ŁOCK 0900, Lactobacillus rhamnosus ŁOCK 0908, and Lactobacillus casei ŁOCK 0918 in children under 2 years of age with AD and a cow’s milk protein (CMP) allergy. The study enrolled 151 children, who—apart from being treated with a CMP elimination diet—were randomized to receive the probiotic preparation at a daily dose of 10⁹ bacteria or a placebo for three months, with a subsequent nine-month follow-up. The primary outcomes included changes in AD symptom severity assessed with the scoring AD (SCORAD) index and in the proportion of children with symptom improvement (a SCORAD score decreased by at least 30% in comparison with that at baseline). After the three-month intervention, both the probiotic and placebo groups showed a significant (p < 0.0001) decrease in SCORAD scores, which was maintained nine months later. The percentage of children who showed improvement was significantly higher in the probiotic than in the placebo group (odds ratio (OR) 2.56; 95% confidence interval (CI) 1.13–5.8; p = 0.012) after three months. Probiotics induced SCORAD improvement mainly in allergen sensitized patients (OR 6.03; 95% CI 1.85–19.67, p = 0.001), but this positive effect was not observed after nine months. The results showed that the mixture of probiotic ŁOCK strains offers benefits for children with AD and CMP allergy. Further research is necessary to assess the effect of probiotic supplementation on the development of immune tolerance (NCT04738565).

Rhinitis prevalence and association with atopic dermatitis: A systematic review and meta-analysis

BACKGROUND

Atopic dermatitis (AD) and rhinitis are common atopic diseases that may co-occur owing to an overlap in pathophysiology. Although most cases of both diseases are mild and managed with topical anti-inflammatory medicaments, the advent of new systemic and biologic treatments targeting type 2 inflammation in both diseases warrants further insight in the exact overlap of AD and rhinitis.

OBJECTIVE

To determine the association between AD and rhinitis.

METHODS

A systematic review and meta-analysis of the databases PubMed, Embase, and CNKI were performed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Pooled prevalence and pooled odds ratios (ORs) with 95% confidence intervals (95% CIs) were calculated.

RESULTS

The search resulted in 10,422 citations, and 341 and 302 articles were included in the qualitative and quantitative analyses, respectively. The pooled prevalence of rhinitis was 40.5% (95% CI 39.0-42.0) in patients with AD and 18.0% (95% CI 16.7-19.2) in the reference individuals without AD. The pooled prevalence of having both rhinitis and asthma was 14.2% (95% CI 13.0-15.5) in patients with AD. There was an association between AD and rhinitis (OR 3.00, 95% CI 2.83-3.18), allergic rhinitis (OR 3.25, 95% CI 2.26-4.66), and nonallergic rhinitis (OR 1.99, 95% CI 1.39-2.86), respectively.

CONCLUSION

Rhinitis, both allergic and nonallergic forms, is very common in patients with AD. Future investigations should clarify how medications targeting both diseases should be indicated in these patients.

Eosinophil microRNAs Play a Regulatory Role in Allergic Diseases Included in the Atopic March

(1) Background: The atopic march is defined by the increased prevalence of allergic diseases after atopic dermatitis onset. In fact, atopic dermatitis is believed to play an important role in allergen sensitization via the damaged skin barrier, leading to allergic diseases such as allergic asthma and allergic rhinitis. The eosinophil, a pro-inflammatory cell that contributes to epithelial damage, is one of the various cells recruited in the inflammatory reactions characterizing these diseases. Few studies were conducted on the transcriptome of this cell type and even less on their specific microRNA (miRNA) profile, which could modulate pathogenesis of allergic diseases and clinical manifestations post-transcriptionally. Actually, their implication in allergic diseases is not fully understood, but they are believed to play a role in inflammation-related patterns and epithelial cell proliferation. (2) Methods: Next-generation sequencing was performed on RNA samples from eosinophils of individuals with atopic dermatitis, atopy, allergic rhinitis and asthma to obtain differential counts of primary miRNA (pri-miRNA); these were also analyzed for asthma-related phenotypes such as forced expiratory volume in one second (FEV₁), immunoglobulin E (IgE) and provocative concentration of methacholine inducing a 20% fall in forced expiratory volume in 1 s (PC₂₀) levels, as well as FEV₁ to forced vital capacity (FEV₁/FVC) ratio. (3) Results: Eighteen miRNAs from eosinophils were identified to be significantly different between affected individuals and unaffected ones. Based on counts from these miRNAs, individuals were then clustered into groups using Ward's method on Euclidian distances. Groups were found to be explained by asthma diagnosis, familial history of respiratory diseases and allergic rhinitis as well as neutrophil counts. (4) Conclusions: The 18 differential miRNA counts for the studying phenotypes allow a better understanding of the epigenetic mechanisms underlying the development of the allergic diseases included in the atopic march.

Atopic dermatitis: Correlation of severity with allergic sensitization and eosinophilia

Background: It is widely acknowledged that food sensitization is related to atopic dermatitis in infants and young children. Objective: To investigate the association of aeroallergen sensitization with increased rates and severity of atopic dermatitis in school children. Methods: We enrolled 576 children (mean age, 9.4 ± 1.8 years) from six elementary schools. Atopic dermatitis was diagnosed by questionnaires, and severity was rated by physical examinations graded by using the Scoring Atopic Dermatitis (SCORAD) index. Skin-prick tests to 22 common allergens (6 aeroallergens and 16 food allergens) were conducted. Logistic and linear regression analyses were performed by using two models: model I adjusted for age, sex, and body mass index z score; and model II adjusted for all model I factors plus asthma and allergic rhinitis. Results: We diagnosed atopic dermatitis in 22.4% (n = 129) of the children, sensitization to foods in 48.3% (n = 278), and sensitization to aeroallergens in 11.3% (n = 65). A total of 26.2% of the children (n = 149) had mild and 6.5% had moderate-to-severe symptoms and signs of atopic dermatitis (n = 37). Atopic dermatitis was associated with sensitization to aeroallergens and eosinophilia (model I), but this risk was no longer significant after additional adjustment for current allergic status (model II). However, the relationship of the total SCORAD score with aeroallergen sensitization and eosinophilia was significant in model I and model II. Conclusion: The severity of atopic dermatitis correlated with the extent of allergic sensitization and eosinophilia. Analysis of our results suggests that more sensitization to dust mites and eosinophilia are related to increased rates and high severity scores of atopic dermatitis.

Distribution of serum specific IgE in children with allergic conjunctivitis and analysis of its concomitant allergic diseases

BACKGROUND

Allergic conjunctivitis (AC) is predominantly caused by serum specific-IgE (sIgE)-mediated type I allergy. This study aims to analyze the distribution of sIgE in children with AC, and the concomitant allergic diseases.

METHODS

The clinical data from 310 children, diagnosed with AC and admitted to our hospital from January 2017 to January 2019 were retrospectively collected. The children were divided into three groups: infant group (2 months to 1 year old, 91 cases), child group (1 to 3 years old, 112 cases), and preschool group (3 to 6 years old, 107 cases). Children in every group were analyzed for positive rates, the number of positive sIgE types, the distribution of positive inhaling and ingesting allergens and concomitant allergic diseases.

RESULTS

The sIgE positive rate of infant was significantly lower than that of the other two groups, and the number of 18.75% sIgE positive species was 1. The number of sIgE positive species in the child group and preschool group was more than 2 (78.30%, 71.15%). The positive rate of sIgE to dust mites, house dust, animal dander, eggs, beef, mutton and mango in the preschool group was significantly higher than the other groups (P<0.05). The positive rate of sIgE to milk in infant group was significantly higher than the other two groups (P<0.05). Children in the preschool group showed the highest incidence of AC, AC + allergic rhinitis, AC + allergic rhinitis + wheezing, while those in the infant group displayed the lowest incidence (P<0.05). AC + gastrointestinal allergy, AC + atopic dermatitis, AC + gastrointestinal allergy + atopic dermatitis in infant group was significantly higher than the other two groups (P<0.05). Patients in the child group displayed a significantly higher incidence of AC + infant wheezing than the other two groups (P<0.05).

CONCLUSIONS

We correlated children's age with the positive rate and gradual increase in types of AC allergens. Concomitant allergic diseases of children with AC at different ages conform to the natural course of allergic diseases. In clinic, improving the diagnostic efficiency of AC in children, and early interventional treatment will positively contribute to their prognosis, and reduce the risk of other allergic diseases.

Recent advances in mechanisms of food allergy and anaphylaxis

Food allergens are innocuous proteins that promote tolerogenic adaptive immune responses in healthy individuals yet in other individuals induce an allergic adaptive immune response characterized by the presence of antigen-specific immunoglobulin E and type-2 immune cells. The cellular and molecular processes that determine a tolerogenic versus non-tolerogenic immune response to dietary antigens are not fully elucidated. Recently, there have been advances in the identification of roles for microbial communities and anatomical sites of dietary antigen exposure and presentation that have provided new insights into the key regulatory steps in the tolerogenic versus non-tolerogenic decision-making processes. Herein, we will review and discuss recent findings in cellular and molecular processes underlying food sensitization and tolerance, immunological processes underlying severity of food-induced anaphylaxis, and insights obtained from immunotherapy trials.

Halting the March: Primary Prevention of Atopic Dermatitis and Food Allergies

Atopic dermatitis (AD) is one of the most common inflammatory skin conditions, affecting 15% to 30% of children and 2% to 10% of adults. Population-based studies suggest that having AD is associated with subsequent development of other atopic diseases, in what is known as the "atopic march." We will provide an overview of studies that investigate primary prevention strategies for the first 2 diseases in the march, namely, AD and food allergies (FA). These strategies include emollients, breastfeeding, microbial exposures, probiotics, vitamin D and UV light, water hardness, and immunotherapy. Some studies, including randomized controlled trials on emollients and microbial supplementation, have found encouraging results; however, the evidence remains limited and contradictory. With regard to breastfeeding, microbial and lifestyle exposures, vitamin D and UV light, water hardness, and immunotherapy, the lack of randomized controlled trials makes it difficult to draw definitive conclusions. Current American Academy of Pediatrics guidelines support the idea that breastfeeding for 3 to 4 months can decrease AD incidence in children less than 2 years old. Recommendations regarding a direct relationship between breastfeeding on FA, however, cannot be made because of insufficient data. Regarding microbial supplementation, most guidelines do not recommend probiotics or prebiotics for the purpose of preventing allergic diseases because of limited evidence. Before definitive conclusions can be made regarding these interventions, more well-designed, longitudinal, and randomized controlled trials, particularly in at-risk populations, are required.

Epicutaneous sensitization to food allergens in atopic dermatitis: What do we know?

Atopic dermatitis (AD) is a chronic inflammatory skin disease mainly affecting children, which has no definitive curative therapy apart from natural outgrowing. AD is persistent in 30%-40% of children. Epithelial barrier dysfunction in AD is a significant risk factor for the development of epicutaneous food sensitization, food allergy, and other allergic disorders. There is evidence that prophylactic emollient applications from birth may be useful for primary prevention of AD, but biomarkers are needed to guide cost-effective targeted therapy for high-risk individuals. In established early-onset AD, secondary preventive strategies are needed to attenuate progression to other allergic disorders such as food allergy, asthma, and allergic rhinitis (the atopic march). This review aims to describe the mechanisms underpinning the development of epicutaneous sensitization to food allergens and progression to clinical food allergy; summarize current evidence for interventions to halt the progression from AD to food sensitization and clinical food allergy; and highlight unmet needs and directions for future research.

Imbalance of Gut Streptococcus, Clostridium, and Akkermansia Determines the Natural Course of Atopic Dermatitis in Infant

Purpose

The roles of gut microbiota on the natural course of atopic dermatitis (AD) are not yet fully understood. We investigated whether the composition and function of gut microbiota and short-chain fatty acids (SCFAs) at 6 months of age could affect the natural course of AD up to 24 months in early childhood.

Methods

Fecal samples from 132 infants were analyzed using pyrosequencing, including 84 healthy controls, 22 transient AD and 26 persistent AD subjects from the Cohort for Childhood Origin of Asthma and Allergic Diseases (COCOA) birth cohort. The functional profile of the gut microbiome was analyzed by whole-metagenome sequencing. SCFAs were measured using gas chromatography-mass spectrometry.

Results

Low levels of Streptococcus and high amounts of Akkermansia were evident in transient AD cases, and low Clostridium, Akkermansia and high Streptococcus were found in children with persistent AD. The relative abundance of Streptococcus positively correlated with scoring of AD (SCORAD) score, whereas that of Clostridium negatively correlated with SCORAD score. The persistent AD group showed decreased gut microbial functional genes related to oxidative phosphorylation compared with healthy controls. Butyrate and valerate levels were lower in transient AD infants compared with healthy and persistent AD infants.

Conclusions

Compositions, functions and metabolites of the early gut microbiome are related to natural courses of AD in infants.

Approach to the Assessment and Management of Pediatric Patients with Atopic Dermatitis: A Consensus Document. Section II: Comorbid Disease in Pediatric Atopic Dermatitis

Pediatric atopic dermatitis (AD) is one of the most common skin conditions encountered by health-care providers caring for infants, children, and adolescents. Pediatric patients with AD may present with other allergic and nonallergic comorbidities that require appropriate treatment and referral. They may also experience a trajectory of allergic diseases known as the atopic march, which depends on a complex interaction between genetic and environmental factors and likely involves early epidermal barrier dysfunction. Here we provide a review and clinical recommendations on the assessment and referral of comorbidities in pediatric AD.

Timing of Introduction, Sensitization, and Allergy to Highly Allergenic Foods at Age 3 Years in a General-Population Canadian Cohort

BACKGROUND

Early dietary introduction of highly allergenic foods has been associated with decreased risk of food allergy in high-risk infants.

OBJECTIVE

Early introduction of highly allergenic foods for lower risk infants was examined using Canadian Healthy Infant Longitudinal Development (CHILD) Study data.

METHODS

CHILD participants were recruited from the general population before birth. Every 6 months, caregivers reported food introduction and allergic reactions. At ages 1 and 3 years, sensitization to peanut, egg, and cow's milk was measured by skin prick testing (SPT) and atopic dermatitis diagnosed at clinical visits. Multivariable logistic regression was used to examine associations between timing of introduction to peanut, egg, and cow's milk and the presence at 3 years of sensitization (positive SPT) and probable clinical IgE-mediated allergy (sensitization with no current consumption and convincing history of allergic reaction to the specific food).

RESULTS

Among 2669 CHILD participants at age 3 years, 101 (3.80%) showed sensitization to peanut, 59 (2.21%) to egg, and 30 (1.12%) to cow's milk; 46 (1.78%) showed probable clinical IgE-mediated allergy to peanut, 4 (0.16%) to egg, and 2 (0.08%) to cow's milk. Infants introduced to peanut after 12 months had increased odds of sensitization (odds ratio [OR]: 2.38, 95% confidence interval [CI]: 1.39-4.07) and probable clinical allergy (OR: 4.04, 95% CI: 1.66-9.85) to peanut at 3 years. Associations persisted after exclusion of high-risk infants with moderate-to-severe atopic dermatitis in the first year/egg sensitization at 1 year.

CONCLUSIONS

General-population infants introduced to peanut after age 12 months were more likely to have sensitization and probable clinical allergy to peanut at 3 years.

Evolution of pathologic T-cell subsets in patients with atopic dermatitis from infancy to adulthood

BACKGROUND

The circulating immune phenotype was defined in adults and young children with early atopic dermatitis (AD), but chronologic changes in the blood of infants and children with AD through adolescence have not been explored.

OBJECTIVE

We sought to compare immune activation and cytokine polarization in the blood of 0- to 5-year-old (n = 39), 6- to 11-year-old (n = 26), 12- to 17-year-old (n = 21) and 18-year-old or older (n = 43) patients with AD versus age-matched control subjects.

METHODS

Flow cytometry was used to measure IFN-γ, IL-9, IL-13, IL-17, and IL-22 cytokine levels in CD4⁺/CD8⁺ T cells, with inducible costimulator molecule and HLA-DR defining midterm and long-term T-cell activation, respectively, within skin-homing/cutaneous lymphocyte antigen (CLA)⁺ versus systemic/CLA^- T cells. Unsupervised clustering differentiated patients based on their blood biomarker frequencies.

RESULTS

Although CLA⁺ T_H1 frequencies were significantly lower in infants with AD versus all older patients (P < .01), frequencies of CLA⁺ T_H2 T cells were similarly expanded across all AD age groups compared with control subjects (P < .05). After infancy, CLA^- T_H2 frequencies were increased in patients with AD in all age groups, suggesting systemic immune activation with disease chronicity. IL-22 frequencies serially increased from normal levels in infants to highly significant levels in adolescents and adults compared with levels in respective control subjects (P < .01). Unsupervised clustering aligned the AD profiles along an age-related spectrum from infancy to adulthood (eg, inducible costimulator molecule and IL-22).

CONCLUSIONS

The adult AD phenotype is achieved only in adulthood. Unique cytokine signatures characterizing individual pediatric endotypes might require age-specific therapies. Future longitudinal studies, comparing the profile of patients with cleared versus persistent pediatric AD, might define age-specific changes that predict AD clearance.

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.

Atopic Dermatitis Is a Barrier Issue, Not an Allergy Issue

Atopic dermatitis (AD) is a chronic, relapsing disease that typically manifests in childhood and improves with age. Studies have demonstrated that the presence of AD increases the risk of developing food allergy, allergic rhinitis, and asthma later in life. Although children with AD are more likely to produce allergen-specific immunoglobulin E, there is conflicting evidence that allergen avoidance improves disease severity. Furthermore, food-elimination diets in patients with AD may increase the risk of developing immediate, life-threatening reactions to the removed food. The most effective treatments of AD aim to repair and protect the skin barrier and decrease inflammation.

Longitudinal atopic dermatitis control and persistence vary with timing of disease onset in children: A cohort study

BACKGROUND

Wide variation exists in the timing of atopic dermatitis (AD) disease onset among children. Distinct trajectories of early-onset, mid-onset, and late-onset AD have been previously described.

OBJECTIVE

To evaluate longitudinal disease control and persistence with respect to age at onset of AD.

METHODS

A cohort study was performed using the Pediatric Eczema Elective Registry, a prospective observational cohort of subjects with childhood-onset AD. AD control and persistence were assessed biannually for up to 10 years.

RESULTS

A total of 8015 subjects with 41,934 person-years of follow-up were included. In longitudinal analyses using generalized linear latent and mixed modeling, older age at onset of AD was associated with better disease control and less-persistent AD. For each additional year of age at onset of AD, the adjusted odds ratios for poorer AD control and for persistent AD were 0.93 (95% confidence interval, 0.91-0.94) and 0.84 (95% confidence interval, 0.80-0.88), respectively. Differences in AD control and persistence among subjects with early-, mid-, and late-onset AD were most pronounced from early adolescence onward.

LIMITATIONS

Misclassification bias may arise from using self-reported data on age at onset. Attrition and missing data in longitudinal studies may introduce bias.

CONCLUSION

Early-, mid-, and late-onset pediatric AD appear to be clinically distinct subtypes of the disease.

Early immunologic changes during the onset of atopic dermatitis

OBJECTIVE

Atopic dermatitis (AD), which is commonly called eczema, is the most common chronic inflammatory skin disease. The pipeline of new targeted treatments is currently expanding, a development that is largely based on our increasing understanding of disease mechanisms. Mechanistic insights have long been based on long-standing adult AD. Recently, studies also investigated early pediatric AD at disease onset, and revealed several differences in barrier and immune properties when compared with long-standing adult AD. This review focuses on immunological changes very early in life that predispose to the development of AD, and summarizes characteristics of the molecular AD phenotype in this age group.

DATA SOURCES

Review of published literature.

STUDY SELECTIONS

Studies investigating human AD at disease onset in newborns, toddlers, and young children, in comparison with adults with long-standing disease.

RESULTS

Already in cord blood, increased Th2 and decreased Th1 levels were found to increase the risk of AD development. Both pediatric and adult AD share Th2/Th22 activation and defects in lipid barrier deposition and tight junction formation, but Th1 activation and epidermal differentiation complex defects are largely absent in pediatric AD.

CONCLUSION

Immune changes predisposing to AD development are present very early in life. During the first months of disease, AD shows various differences in immune and barrier properties from long-standing adult AD, which might necessitate tailored treatment approaches depending on the age of the patient.

Influences on allergic mechanisms through gut, lung, and skin microbiome exposures

In industrialized societies the incidence of allergic diseases like atopic dermatitis, food allergies, and asthma has risen alarmingly over the last few decades. This increase has been attributed, in part, to lifestyle changes that alter the composition and function of the microbes that colonize the skin and mucosal surfaces. Strategies that reverse these changes to establish and maintain a healthy microbiome show promise for the prevention and treatment of allergic disease. In this Review, we will discuss evidence from preclinical and clinical studies that gives insights into how the microbiota of skin, intestinal tract, and airways influence immune responses in the context of allergic sensitization.

Mechanisms by Which Atopic Dermatitis Predisposes to Food Allergy and the Atopic March

The Atopic march denotes the progression from atopic dermatitis (AD) to the development of other allergic disorders such as immunoglobulin (Ig) E-mediated food allergy, allergic rhinitis and asthma in later childhood. There is increasing evidence from prospective birth cohort studies that early-onset AD is a risk factor for other allergic diseases or is found in strong association with them. Animal studies now provide mechanistic insights into the pathways that may be responsible for triggering the progression from the skin barrier dysfunction seen in AD to epicutaneous sensitization, food allergy and allergic airway disorders. Recent large randomized controlled trials have demonstrated the efficacy of early interventions targeted at AD and food allergy prevention. These show great promise for research into future strategies aimed at prevention of the atopic march.

New insights into the phenotypes of atopic dermatitis linked with allergies and asthma in children: An overview

Atopic dermatitis (AD) is a complex disease with multiple causes and complex mechanistic pathways according to age of onset, severity of the illness, ethnic modifiers, response to therapy and triggers. A group of difficult-to-manage patients characterized by early-onset AD and severe lifelong disease associated with allergic asthma and/or food allergy (FA) has been identified. In this study, we focus on these severe phenotypes, analysing their links with other atopic comorbidities, and taking into account the results from recent cohort studies and meta-analyses. The main hypothesis that is currently proposed to explain the onset of allergic diseases is an epithelial barrier defect. Thus, the atopic march could correspond to an epithelial dysfunction, self-sustained by a secondary allergenic sensitization, explaining the transition from AD to allergic asthma. Furthermore, AD severity seems to be a risk factor for associated FA. Results from population-based, birth and patient cohorts show that early-onset and severe AD, male gender, parental history of asthma, and early and multiple sensitizations are risk factors leading to the atopic march and the development of asthma. The importance of environmental factors should be recognized in these high-risk children and prevention programs adapted accordingly. Effective targeted therapies to restore both barrier function and to control inflammation are necessary; early emollient therapy is an important approach to prevent AD in high-risk children. Clinicians should also keep in mind the specific risk of atopic comorbidities in case of filaggrin loss-of-function mutations and the rare phenotypes of orphan syndromes due to heritable mutations in skin barrier components.

Mechanism for initiation of food allergy: Dependence on skin barrier mutations and environmental allergen costimulation

BACKGROUND

Mechanisms for the development of food allergy in neonates are unknown but clearly linked in patient populations to a genetic predisposition to skin barrier defects. Whether skin barrier defects contribute functionally to development of food allergy is unknown.

OBJECTIVE

The purpose of the study was to determine whether skin barrier mutations, which are primarily heterozygous in patient populations, contribute to the development of food allergy.

METHODS

Mice heterozygous for the filaggrin (Flg)ft and Tmem79ma mutations were skin sensitized with environmental and food allergens. After sensitization, mice received oral challenge with food allergen, and then inflammation, inflammatory mediators, and anaphylaxis were measured.

RESULTS

We define development of inflammation, inflammatory mediators, and food allergen-induced anaphylaxis in neonatal mice with skin barrier mutations after brief concurrent cutaneous exposure to food and environmental allergens. Moreover, neonates of allergic mothers have increased responses to suboptimal sensitization with food allergens. Importantly, responses to food allergens by these neonatal mice were dependent on genetic defects in skin barrier function and on exposure to environmental allergens. ST2 blockade during skin sensitization inhibited the development of anaphylaxis, antigen-specific IgE, and inflammatory mediators. Neonatal anaphylactic responses and antigen-specific IgE were also inhibited by oral pre-exposure to food allergen, but interestingly, this was blunted by concurrent pre-exposure of the skin to environmental allergen.

CONCLUSION

These studies uncover mechanisms for food allergy sensitization and anaphylaxis in neonatal mice that are consistent with features of human early-life exposures and genetics in patients with clinical food allergy and demonstrate that changes in barrier function drive development of anaphylaxis to food allergen.

Particular characteristics of atopic eczema in tropical environments. The Tropical Environment Control for Chronic Eczema and Molecular Assessment (TECCEMA) cohort study

Background

Atopic dermatitis is a prevalent health problem in the world. Allergic sensitization is an important risk factor, but the roles of other factors, inherent in tropic region, are unknown.

Objective

A cohort study was designed in a tropical city to investigate molecular and environmental risk factors for eczema, considering as particular features perennial exposure to mites, poor living conditions and others tropical characteristics.

Methods

433 patients were included at baseline and biological samples were collected during 24 months of follow-up. Clinical information was collected using questionnaires (SCORAD, DLQI and a subjective scale) during each clinical assessment.

Results

The prevalence of atopic eczema was 93%, with similar frequency between children and adults; parents history of eczema and polysensitization to mites, dogs, cats, cockroaches and birds, were risk factors for severe and persistent eczema and allergic comorbidities. Food sensitization was present in 16% of patients but food-induced allergies were scarce. Psychiatric, dental and ocular disorders were the most frequent non-allergic comorbidities.

Study limitations

selection bias.

Conclusion

We presented a tropical cohort of patients with eczema and we identified some risk factors for severe and persistent dermatitis. Some patterns of sensitization were associated with severe eczema and respiratory symptoms, and the natural history of "atopic march" is different to that described in some industrialized countries. The collection of biological samples will contribute to the understanding of the gene/environment interactions leading to allergy inception and evolution.

Reporting of sex and gender in randomized controlled trials in Canada: a cross-sectional methods study

BACKGROUND

Accurate reporting on sex and gender in health research is integral to ensuring that health interventions are safe and effective. In Canada and internationally, governments, research organizations, journal editors, and health agencies have called for more inclusive research, provision of sex-disaggregated data, and the integration of sex and gender analysis throughout the research process. Sex and gender analysis is generally defined as an approach for considering how and why different subpopulations (e.g., of diverse genders, ages, and social locations) may experience health conditions and interventions in different or similar ways.The objective of this study was to assess the extent and nature of reporting about sex and/or gender, including whether sex and gender analysis (SGA) was carried out in a sample of Canadian randomized controlled trials (RCTs) with human participants.

METHODS

We searched MEDLINE from 01 January 2013 to 23 July 2014 using a validated filter for identification of RCTs, combined with terms related to Canada. Two reviewers screened the search results to identify the first 100 RCTs that were either identified in the trial publication as funded by a Canadian organization or which had a first or last author based in Canada. Data were independently extracted by two people from 10% of the RCTs during an initial training period; once agreement was reached on this sample, the remainder of the data extraction was completed by one person and verified by a second.

RESULTS

The search yielded 1433 records. We screened 256 records to identify 100 RCTs which met our eligibility criteria. The median sample size of the RCTs was 107 participants (range 12-6085). While 98% of studies described the demographic composition of their participants by sex, only 6% conducted a subgroup analysis across sex and 4% reported sex-disaggregated data. No article defined "sex" and/or "gender." No publication carried out a comprehensive sex and gender analysis.

CONCLUSIONS

Findings highlight poor uptake of sex and gender considerations in the Canadian RCT context and underscore the need for better articulated guidance on sex and gender analysis to improve reporting of evidence, inform policy development, and guide future research.

Variations in risk of asthma and seasonal allergies between early- and late-onset pediatric atopic dermatitis: A cohort study

BACKGROUND

Atopic dermatitis is associated with other allergic conditions, but variations in this "atopic march" are poorly understood.

OBJECTIVE

To determine the impact of the age of atopic dermatitis onset on the risk for asthma and seasonal allergies.

METHODS

A cohort study was performed using the Pediatric Eczema Elective Registry, which is an observational cohort of subjects with pediatric onset atopic dermatitis.

RESULTS

In total, 3966 children were included, and 73% reported atopic dermatitis onset before age 2 years. At baseline, subjects with atopic dermatitis onset at ages 3 to 7 or 8 to 17 years had significantly lower rates of seasonal allergies and asthma than those with onset before age 2. During follow-up, the adjusted relative risks for incident seasonal allergies were 0.82 (95% confidence interval, 0.72-0.91) and 0.64 (95% CI confidence interval, 0.47-0.83) in the 3- to 7- and 8- to 17-years-old at onset groups compared with the age 2 years or younger at onset group. The adjusted risk for incident asthma was not significantly different between the older onset groups and the earliest onset group.

LIMITATIONS

Misclassification bias may arise from using self-reported onset age data.

CONCLUSIONS

The timing of atopic dermatitis onset may explain part of the variation in the atopic march. These findings may improve future risk stratification of patients for treatment.

Allergy march of Chinese children with infantile allergic symptoms: a prospective multi-center study

BACKGROUND

Allergy march refers to progression of allergic diseases from infantile food allergy to the development of asthma and allergic rhinitis (AR). Evidence come mostly from studies in European countries. This study aimed to investigate allergy march in Chinese children with infantile food protein allergy (FPA) with a special focus on the effect of different formula interventions.

METHODS

From 2008 to 2010, 153 infants diagnosed with FPA were recruited in five tertiary hospitals across China. They were randomly treated with amino-acid-based formula or soy-protein-based formula for a period of 3 months. Long-term follow-up was performed when they reached early school age, using questionnaires, physical examinations, and serum-specific immunoglobulin E.

RESULTS

The overall follow-up rate was 73.20%. In patients who reached their early school years, the prevalence of physician-diagnosed AR and asthma were 43.75% and 23.21%, respectively. Only 40% of the subjects remained positive for food sensitizations upon follow-up. Twenty-six subjects receiving aeroallergen screening tests in infancy all proved negative, but upon follow-up, 65.57% were sensitized to aeroallergens (P=0.005). No significant difference between the effects of amino-acid-based formula and soy-protein-based formula on children's allergy march was observed.

CONCLUSIONS

A high proportion (47.32%) of Chinese infants with early allergic symptoms developed respiratory allergies by their early school years. Most food-sensitized infants outgrew their condition several years later, but then aeroallergen sensitization often occurred. Amino-acid-based formula showed no advantages over soy protein-based formula with respect to arresting the allergy march.

Age at onset and persistence of eczema are related to subsequent risk of asthma and hay fever from birth to 18 years of age

BACKGROUND

Few studies have simultaneously addressed the importance of age of onset and persistence of eczema for the subsequent development of asthma and hay fever, particularly into early adulthood.

METHODS

A high-risk birth cohort was recruited comprising 620 infants, who were then followed up frequently until 2 years of age, annually from age 3 to 7, then at 12 and 18 years, to document any episodes of eczema, current asthma, and hay fever. The generalized estimation equation technique was used to examine asthma and hay fever outcomes at 6 (n = 325), 12 (n = 248) and 18 (n = 240) years, when there was consistency of associations across the follow-ups.

RESULTS

Very early-onset persistent (onset <6 months, still present from 2 to 5 years) eczema was related to current asthma (adjusted OR = 3.2 [95% CI = 1.7-6.1]), as was very early-onset remitting eczema (onset <6 months but not present from 2-5 years, OR = 2.7, 95% CI = 1.0-7.2) and early-onset persistent eczema (onset from 6-24 months, OR = 2.3, 95% CI = 1.2-4.7). Late-onset eczema (commenced from 2-5 years) was associated with increased risk of asthma at 12 years (OR = 3.0, 95% CI=1.1-8.2) but not at age 6 years. Only very early-onset persistent eczema was associated with increased risk of hay fever (aOR = 2.4, 95% CI = 1.4-4.1).

CONCLUSION AND CLINICAL RELEVANCE

Eczema which commences in early infancy and persists into toddler years is strongly associated with asthma, and to a lesser extent hay fever, in high-risk children. If these associations are causal, prevention of early-life eczema might reduce the risk of respiratory allergy.

Sensitization trajectories in childhood revealed by using a cluster analysis

BACKGROUND

Assessment of sensitization at a single time point during childhood provides limited clinical information. We hypothesized that sensitization develops as specific patterns with respect to age at debut, development over time, and involved allergens and that such patterns might be more biologically and clinically relevant.

OBJECTIVE

We sought to explore latent patterns of sensitization during the first 6 years of life and investigate whether such patterns associate with the development of asthma, rhinitis, and eczema.

METHODS

We investigated 398 children from the at-risk Copenhagen Prospective Studies on Asthma in Childhood 2000 (COPSAC₂₀₀₀) birth cohort with specific IgE against 13 common food and inhalant allergens at the ages of ½, 1½, 4, and 6 years. An unsupervised cluster analysis for 3-dimensional data (nonnegative sparse parallel factor analysis) was used to extract latent patterns explicitly characterizing temporal development of sensitization while clustering allergens and children. Subsequently, these patterns were investigated in relation to asthma, rhinitis, and eczema. Verification was sought in an independent unselected birth cohort (BAMSE) constituting 3051 children with specific IgE against the same allergens at 4 and 8 years of age.

RESULTS

The nonnegative sparse parallel factor analysis indicated a complex latent structure involving 7 age- and allergen-specific patterns in the COPSAC₂₀₀₀ birth cohort data: (1) dog/cat/horse, (2) timothy grass/birch, (3) molds, (4) house dust mites, (5) peanut/wheat flour/mugwort, (6) peanut/soybean, and (7) egg/milk/wheat flour. Asthma was solely associated with pattern 1 (odds ratio [OR], 3.3; 95% CI, 1.5-7.2), rhinitis with patterns 1 to 4 and 6 (OR, 2.2-4.3), and eczema with patterns 1 to 3 and 5 to 7 (OR, 1.6-2.5). All 7 patterns were verified in the independent BAMSE cohort (R² > 0.89).

CONCLUSION

This study suggests the presence of specific sensitization patterns in early childhood differentially associated with development of clinical outcomes. Using such patterns in future research might provide more robust and clinically relevant results.