Associations of eczema phenotypes with emotional and behavioural problems from birth until school age. The Generation R Study

Atopic dermatitis and risk of major neuropsychiatric disorders in children: A population-based cohort study

BACKGROUND

Paediatric atopic dermatitis (AD) has been linked to neuropsychiatric comorbidities such as depression, anxiety and attention-deficit/hyperactivity disorder (ADHD). However, longitudinal data are limited, and the effect of AD severity on neuropsychiatric outcomes requires further characterization.

OBJECTIVES

To determine the risk of several major neuropsychiatric conditions in children with AD.

METHODS

We analysed UK health records data in a population-based cohort study. Each patient <18 years old with AD was matched to up to five unaffected patients on age, practice and index date. Treatments served as proxies for AD severity, which was analysed in a time-updated manner. Outcomes were incident anxiety, depression, bipolar disorder, schizophrenia, ADHD, autism, obsessive-compulsive disorder (OCD), suicidal ideation or attempt, and completed suicide.

RESULTS

A total of 409,431 children with AD (93.2% mild, 5.5% moderate, 1.3% severe) were compared to 1,809,029 children without AD. In Cox regression models adjusted for age, sex, socioeconomic status and other atopic comorbidities, no statistically significant relationships were observed between AD and incident anxiety (HR 1.01, 95% CI 0.99-1.03), ADHD (1.02, 0.97-1.06), autism (1.02, 0.98-1.06), bipolar disorder (1.08, 0.85-1.36), suicidal ideation/attempt (0.98, 0.95-1.01) or completed suicide (0.85, 0.64-1.14). Children with AD were less likely to develop depression (0.93, 0.91-0.95) or schizophrenia (0.72, 0.54-0.95) but more likely to develop OCD (1.26, 1.16-1.37). However, there was substantial variation by AD severity and age in both the direction and magnitude of effect for many of the neuropsychiatric conditions examined.

CONCLUSIONS

The was no substantial impact of AD on the overall risk of many neuropsychiatric conditions in children, but disease severity and age may be important modifying factors. Additional research is needed to further dissect the complex relationship between paediatric AD and neuropsychiatric comorbidities.

Classifying atopic dermatitis: a systematic review of phenotypes and associated characteristics

Atopic dermatitis is a heterogeneous disease, accompanied by a wide variation in disease presentation and the potential to identify many phenotypes that may be relevant for prognosis and treatment. We aimed to systematically review previously reported phenotypes of atopic dermatitis and any characteristics associated with them. Ovid EMBASE, Ovid MEDLINE and Web of Science were searched from inception till the 12th of February 2021 for studies attempting to classify atopic dermatitis. Primary outcomes are atopic dermatitis phenotypes and characteristics associated with them in subsequent analyses. A secondary outcome is the methodological approach used to derive them. In total, 8,511 records were found. By focusing only on certain clinical phenotypes, 186 studies were eligible for inclusion. The majority of studies were hospital-based (59%, 109/186) and cross-sectional (76%, 141/186). The number of included patients ranged from seven to 526,808. Data-driven approaches to identify phenotypes were only used in a minority of studies (7%, 13/186). Ninety-one studies (49%) investigated a phenotype based on disease severity. A phenotype based on disease trajectory, morphology and eczema herpeticum was investigated in 56 (30%), 22 (12%) and 11 (6%) studies, respectively. Thirty-six studies (19%) investigated morphological characteristics in other phenotypes. Investigated associated characteristics differed between studies. In conclusion, we present an overview of phenotype definitions used in literature for severity, trajectory, morphology and eczema herpeticum, including associated characteristics. There is a lack of uniform and consistent use of atopic dermatitis phenotypes across studies.

Associations between T cells and attention problems in the general pediatric population: The Generation R study

Objective

The pathogenesis of attention-deficit/hyperactivity disorder (ADHD) is currently unclear. We hypothesized that chronic immune activation, as indexed by T and B cells, plays a role in the pathophysiology of attention problems. Therefore, we examined T and B cell subsets in a general pediatric population with information on attention problems.

Methods

We included 756 10-year-old children from the Generation R population-based cohort. Eleven-color flow cytometry was performed on peripheral blood samples to determine T and B cell subsets. The Child Behavior Checklist rated by parents was used to measure attention problems. Data were analyzed using linear regression analyses, adjusting for maternal and child covariates and co-occurring childhood psychopathology.

Results

For T helper 1 (Th1) cells, one standard deviation (SD) increase was associated with 5.3% (95%CI 0.3; 10.5) higher attention problem scores. Furthermore, 1SD increase in CD8+ T cells was associated with 7.5% (95%CI 2.4; 12.7) higher attention problem scores. Within total CD8+ T cells, 1SD increase in naive or central memory cells was associated with 6.9% (95%CI 2.0; 12.1) and 6.4% (95%CI 1.5; 11.6) higher attention problem scores, respectively. No associations between Th2, Treg or B memory cells and attention problem scores were observed.

Conclusion

Higher Th1 and cytotoxic T cell numbers are associated with higher attention problem scores independent of co-occurring psychopathology. This might indicate a possible role of a pro-inflammatory immune profile in childhood attention problems.

The Role of the Environment and Exposome in Atopic Dermatitis

PURPOSE OF REVIEW

Atopic dermatitis (AD) is a chronic inflammatory skin disorder affecting up to 20% of children and up to 5% of adults worldwide, contributing to significant disease-related morbidity in this patient cohort. Its aetiopathogenesis is underpinned by multiple factors, including genetic susceptibility, skin barrier defects, a skewed cutaneous immune response and microbiome perturbation in both the skin and the gut. In this review, we aim to examine the biological effects of key environmental exposures (the sum of which is termed the "exposome") at the population, community and individual levels in order to describe their effect on AD pathogenesis.

RECENT FINDINGS

It is now understood that as well as considering the type of environmental exposure with regard to its effect on AD pathogenesis, the dosage and timing of the exposure are both critical domains that may lead to either exacerbation or amelioration of disease. In this review, we consider the effects of population-wide exposures such as climate change, migration and urbanization; community-specific exposures such as air pollution, water hardness and allergic sensitisation; and individual factors such as diet, microbiome alteration, psychosocial stress and the impact of topical and systemic therapy.

SUMMARY

This review summarises the interaction of the above environmental factors with the other domains of AD pathogenesis, namely, the inherent genetic defects, the skin barrier, the immune system and the cutaneous and gut microbiota. We specifically emphasise the timing and dosage of exposures and its effect on the cellular and molecular pathways implicated in AD.

Association between nasal and nasopharyngeal bacterial colonization in early life and eczema phenotypes

Background

An association has been reported between early life Staphylococcus aureus nasal carriage and higher risk of childhood eczema, but it is unclear whether this relationship is causal and associations with other bacterial species are unclear.

Objective

To examine the associations of early life nasal and nasopharyngeal bacterial carriage with eczema phenotypes, and the direction of any associations identified.

Methods

Among 996 subjects of a population‐based prospective cohort study, nasal swabs for Staphylococcus  aureus, and nasopharyngeal swabs for Streptococcus pneumoniae, Moraxella catarrhalis and Haemophilus influenzae were collected and cultured from age 6 weeks to 6 years. Never, early, mid‐, late transient and persistent eczema phenotypes were identified from parental‐reported physician‐diagnosed eczema from age 6 months until 10 years. Multinomial regression models and cross‐lagged models were applied.

Results

Staphylococcus aureus nasal carriage at 6 months was associated with an increased risk of early transient and persistent eczema (OR (95% CI): 2.69 (1.34, 5.39) and 4.17 (1.12, 15.51)). The associations between Staphylococcus aureus nasal carriage and eczema were mostly cross‐sectional, and not longitudinal. No associations of Staphylococcus pneumoniae, Moraxella catarrhalis and Haemophilus influenza nasopharyngeal bacterial carriage with eczema and eczema phenotypes were observed (OR range (95% CI): 0.71 (0.35, 1.44) to 1.77 (0.84, 3.73)).

Conclusions

Early life Staphylococcus aureus nasal carriage, but not Staphylococcus pneumoniae, Moraxella catarrhalis and Haemophilus influenza nasopharyngeal carriage, was associated with early transient and persistent eczema. Staphylococcus aureus nasal carriage and eczema were mostly cross‐sectionally associated, and not longitudinally, making a causal relationship in either direction unlikely.