Breastfeeding and allergies: time for a change in paradigm?

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.

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.

Immunomodulatory constituents of human breast milk and immunity from bronchiolitis

Background

The mother’s immune status can be achieved by genetic and breastfeeding impact descendants of the immune system. The study aimed to determine whether a mother’s immune status and breastfeeding practices were related to development of bronchiolitis in her infant.

Methods

The frequency of T, B and natural kill (NK) cells in patients’ blood and their mothers’ breast milk was determined using flow cytometry. The concentrations of serum and breast milk IgG and IgD in individual patients and healthy control were determined by enzyme-linked immunosorbent assay (ELISA). The relationships between immunocytes, immunoglobulin and respiratory score (RS) were analyzed by Spearman’s rank correlation test.

Results

The mothers of bronchiolitis patients had lower IgG concentrations in their breast milk when compared to the mothers of healthy children. There was no significant difference in the frequency of T cells, B cells, and NK cells in samples of breast milk. However, significant decreases of CD3+, CD8+ T cells, as well as significant increases of CD4+ T cells and CD19+ B cells were found in the serum of bronchiolitis infants. There were positive correlation relationships between RS and CD3+, CD4+ T cells, IgG and IgD concentrations.

Conclusion

Our data suggested that the mothers of bronchiolitis patients had lower IgG concentration in their breast milk. The breast milk IgG might be absorbed by the breastfeeding infants, which could play important role in resistance of bronchiolitis.

Faecal eosinophil cationic protein and serum immunoglobulin E in relation to infant feeding practices

Background To date, the effects of exclusive breastfeeding duration and timing of solid food introduction on allergy prevention are unclear. The aim of this study was to determine the effect of variable feeding practices on intestinal inflammation in infants using faecal eosinophil cationic protein as a surrogate marker and to assess whether faecal eosinophil cationic protein is associated with serum immunoglobulin E. Methods Subjects ( n = 206) were enrolled from the Prediction of Allergies in Taiwanese CHildren (PATCH) birth cohort study. Stool samples were collected at 6 and 12 months for determining eosinophil cationic protein, and blood was collected for determining total and allergen-specific immunoglobulin E at 12 months. We compared these biomarkers between infants with variable exclusive breastfeeding duration and infants introduced to solid foods at various periods. The association between faecal eosinophil cationic protein, total serum immunoglobulin E and specific immunoglobulin E was also analysed. Results Faecal eosinophil cationic protein was significantly higher in exclusively breastfed infants compared with formula-fed infants and infants who were not exclusively breastfed at 6 months of age ( P < 0.05). At 12 months, infants who were introduced to solid foods at 5-6 months had the lowest faecal eosinophil cationic protein compared with those who were introduced at earlier and later periods. There was no significant association between faecal eosinophil cationic protein and serum immunoglobulin E. Conclusion We found that breastfeeding exclusively for >6 months did not reduce serum immunoglobulin E, but rather increased intestinal inflammation. Faecal eosinophil cationic protein was not associated with total serum immunoglobulin E and specific immunoglobulin E and might not be a useful indictor of immunoglobulin E sensitization in infancy.

Evaluating the efficacy of breastfeeding guidelines on long-term outcomes for allergic disease

BACKGROUND

WHO guidelines advocate breastfeeding for 6 months, and EAACI guideline recommends exclusive breastfeeding for 4-6 months. However, evidence for breastfeeding to prevent asthma and allergic disease is conflicting. We examined whether following recommended breastfeeding guidelines alters the long-term risks of asthma, eczema, rhinitis or atopy.

METHODS

The effect of nonexclusive (0, >0-6, >6 months) and exclusive breastfeeding (0, >0-4, >4 months) on repeated measures of asthma (10, 18 years), eczema, rhinitis, and atopy (1-or-2, 4, 10, 18 years) risks was estimated in the IoW cohort (n = 1456) using log-linear models with generalized estimating equations. The Food Allergy and Intolerance Research (FAIR) cohort (n = 988), also from the IoW, was examined to replicate results.

RESULTS

Breastfeeding (any or exclusive) had no effect on asthma and allergic disease in the IoW cohort. In the FAIR cohort, any breastfeeding for >0-6 months protected against asthma at 10 years (RR = 0.50, 95% CI = 0.32-0.79, P = 0.003), but not other outcomes, whilst exclusive breastfeeding for >4 months protected against repeated rhinitis (RR = 0.36, 95% CI = 0.18-0.71, P = 0.003). Longer breastfeeding was protective against late-onset wheeze in the IoW cohort.

CONCLUSION

The protective effects of nonexclusive and exclusive breastfeeding against long-term allergic outcomes were inconsistent between these colocated cohorts, agreeing with previous observations of heterogeneous effects. Although breastfeeding should be recommended for other health benefits, following breastfeeding guidelines did not appear to afford a consistent protection against long-term asthma, eczema, rhinitis or atopy. Further research is needed into the long-term effects of breastfeeding on allergic disease.

Childhood wheezing, asthma, allergy, atopy, and lung function: different socioeconomic patterns for different phenotypes

Identifying preventable exposures that lead to asthma and associated allergies has proved challenging, partly because of the difficulty in differentiating phenotypes that define homogeneous disease groups. Understanding the socioeconomic patterns of disease phenotypes can help distinguish which exposures are preventable. In the present study, we identified disease phenotypes that are susceptible to socioeconomic variation, and we determined which life-course exposures were associated with these inequalities in a contemporary birth cohort. Participants included children from the Avon Longitudinal Study of Parents and Children, a population-based birth cohort in England, who were born in 1991 and 1992 and attended the clinic at 7–8 years of age (n = 6,378). Disease phenotypes included asthma, atopy, wheezing, altered lung function, and bronchial reactivity phenotypes. Combining atopy with a diagnosis of asthma from a doctor captured the greatest socioeconomic variation, including opposing patterns between phenotype groups: Children with a low socioeconomic position (SEP) had more asthma alone (adjusted multinomial odds ratio = 1.50, 95% confidence interval: 1.21, 1.87) but less atopy alone (adjusted multinomial odds ratio = 0.80, 95% confidence interval: 0.66, 0.98) than did children with high SEP. Adjustment for maternal exposure to tobacco smoke during pregnancy and childhood exposure to tobacco smoke reduced the odds of asthma alone in children with a low SEP. Current inequalities among children who have asthma but not atopy can be prevented by eliminating exposure to tobacco smoke. Other disease phenotypes were not socially patterned or had SEP patterns that were not related to smoke exposure.

Breast-feeding does not protect against allergic sensitization in early childhood and allergy-associated disease at age 7 years

BACKGROUND

Extended breast-feeding is recommended for newborn children at risk of allergy-associated diseases, but the evidence of a protective effect on sensitization and these diseases remains elusive.

OBJECTIVE

The aim of this study was to investigate the effects of the duration of exclusive breast-feeding on the development of sensitization in preschool children.

METHODS

Information on breast-feeding was gathered by interviews involving 335 children aged 1, 6, and 12 months from the Copenhagen Prospective Study on Asthma in Childhood2000 birth cohort born to mothers with a history of asthma. Skin prick test responses and specific IgE levels against 12 common inhalant and 10 food allergens were assessed longitudinally at ages ½ year, 1½ years, 4 years, and 6 years. Eczema, wheeze/asthma, and allergic rhinitis were diagnosed at the Copenhagen Prospective Studies on Asthma in Childhood clinic at 7 years of age, strictly adhering to predefined algorithms. Associations between duration of exclusive breast-feeding and outcomes were analyzed by logistic regression.

RESULTS

We found no significant association between duration of exclusive breast-feeding and development of sensitization in the first 6 years of life (odds ratio [OR]: ½ year, 1.10 [95% CI, 0.90-1.36]; 1½ years, 1.15 [95% CI, 0.97-1.36]; 4 years, 1.08 [95% CI, 0.93-1.25]; and 6 years, 0.96 [95% CI, 0.84-1.10]) or with current eczema, wheeze/asthma, and allergic rhinitis at age 7 years (OR, 1.07 [95% CI, 0.92-1.24]; OR, 0.97 [95% CI, 0.82-1.14]; and OR, 1.02 [95% CI, 0.84-1.23], respectively). Adjusting for reverse causation by excluding children with eczema, wheeze, or a positive skin prick test response before ending exclusive breast-feeding did not alter the results.

CONCLUSION

Exclusive breast-feeding does not affect sensitization in early childhood or associated diseases at 7 years of age in at-risk children.

Risk and protective factors for the development of childhood asthma

Childhood asthma prevalence worldwide has been increasing markedly over several decades. Various theories have been proposed to account for this alarming trend. The disease has a broad spectrum of potential determinants ranging from genetics to lifestyle and environmental factors. Epidemiological observations have demonstrated that several important lifestyle and environmental factors including obesity, urban living, dietary patterns such as food low in antioxidants and fast food, non-breastfeeding, gut flora imbalance, cigarette smoking, air pollution, and viral infection are associated with asthma exacerbations in children. However, only environmental tobacco smoke has been associated with the development of asthma. Despite epidemiological studies indicating that many other factors are probably associated with the development of asthma, the relationships are not considered causal due to the inadequate evidence and inconsistent results from recent studies. This may highlight that sufficient data and exact mechanisms of causality are still in need of further study.

Asthma and obesity in children: current evidence and potential systems biology approaches

Both obesity and asthma are highly prevalent, complex diseases modified by multiple factors. Genetic, developmental, lung mechanical, immunological and behavioural factors have all been suggested as playing a causal role between the two entities; however, their complex mechanistic interactions are still poorly understood and evidence of causality in children remains scant. Equally lacking is evidence of effective treatment strategies, despite the fact that imbalances at vulnerable phases in childhood can impact long-term health. This review is targeted at both clinicians frequently faced with the dilemma of how to investigate and treat the obese asthmatic child and researchers interested in the topic. Highlighting the breadth of the spectrum of factors involved, this review collates evidence regarding the investigation and treatment of asthma in obese children, particularly in comparison with current approaches in 'difficult-to-treat' childhood asthma. Finally, the authors propose hypotheses for future research from a systems-based perspective.

Asthma

Asthma is the most common inflammatory disease of the lungs. The prevalence of asthma is increasing in many parts of the world that have adopted aspects of the Western lifestyle, and the disease poses a substantial global health and economic burden. Asthma involves both the large-conducting and the small-conducting airways, and is characterized by a combination of inflammation and structural remodelling that might begin in utero. Disease progression occurs in the context of a developmental background in which the postnatal acquisition of asthma is strongly linked with allergic sensitization. Most asthma cases follow a variable course, involving viral-induced wheezing and allergen sensitization, that is associated with various underlying mechanisms (or endotypes) that can differ between individuals. Each set of endotypes, in turn, produces specific asthma characteristics that evolve across the lifecourse of the patient. Strong genetic and environmental drivers of asthma interconnect through novel epigenetic mechanisms that operate prenatally and throughout childhood. Asthma can spontaneously remit or begin de novo in adulthood, and the factors that lead to the emergence and regression of asthma, irrespective of age, are poorly understood. Nonetheless, there is mounting evidence that supports a primary role for structural changes in the airways with asthma acquisition, on which altered innate immune mechanisms and microbiota interactions are superimposed. On the basis of the identification of new causative pathways, the subphenotyping of asthma across the lifecourse of patients is paving the way for more-personalized and precise pathway-specific approaches for the prevention and treatment of asthma, creating the real possibility of total prevention and cure for this chronic inflammatory disease.

Soluble CD14, α-and β-defensins in breast milk: association with the emergence of allergy in a high-risk population

As innate immunity factors in breast milk (BM) modulate infants' immune responses, we investigated whether soluble CD14 (sCD14) and defensin levels in BM are associated with the emergence of allergy in childhood. The randomly selected group of 260 mother-child pairs belonged to a randomized, double-blind placebo-controlled trial where 1223 mothers with fetuses at high risk for allergy received for the 4 last wk of pregnancy a mixture of probiotics, or placebo; after birth, the child received the treatment for 6 mo. Children were followed for the emergence of sensitization and allergic symptoms for 5 yr. IgE-mediated allergic disorder was diagnosed in 80 children by the age of 5 yr. Levels of sCD14, human neutrophil peptide (HNP) 1-3 and β-defensin 2 (HBD2) in colostrum and in BM 3 mo post-partum were measured with ELISA. BM sCD14 levels decreased from 0 to 3 mo. HNP1-3 and HBD2 were detected in colostrum, but not in BM 3 mo post-partum. High sCD14 levels in BM 3 mo post-partum were associated with children developing an IgE-mediated allergic disorder by the age of 5 yr. BM HNP1-3, HBD2 or sCD14 levels were not associated with probiotics treatment. Our results suggest that sCD14 in BM influences the emergence of allergy in children with atopic heredity.

Childhood asthma-predictive phenotype

Wheezing is a fairly common symptom in early childhood, but only some of these toddlers will experience continued wheezing symptoms in later childhood. The definition of the asthma-predictive phenotype is in children with frequent, recurrent wheezing in early life who have risk factors associated with the continuation of asthma symptoms in later life. Several asthma-predictive phenotypes were developed retrospectively based on large, longitudinal cohort studies; however, it can be difficult to differentiate these phenotypes clinically as the expression of symptoms, and risk factors can change with time. Genetic, environmental, developmental, and host factors and their interactions may contribute to the development, severity, and persistence of the asthma phenotype over time. Key characteristics that distinguish the childhood asthma-predictive phenotype include the following: male sex; a history of wheezing, with lower respiratory tract infections; history of parental asthma; history of atopic dermatitis; eosinophilia; early sensitization to food or aeroallergens; or lower lung function in early life.

Increased maternal BMI is associated with infant wheezing in early life: a prospective cohort study

Rates of obesity are increasing in women of child bearing age with negative impacts on maternal and offspring health. Emerging evidence suggests in utero origins of respiratory health in offspring of obese mothers but mechanisms are unknown. Changes in maternal cortisol levels are one potential factor as cortisol levels are altered in obesity and cortisol is separately implicated in development of offspring wheeze. We aimed to assess whether increased pre-pregnancy maternal body mass index (BMI) was associated with offspring early life wheezing, and whether this was mediated by altered cortisol levels in the mother. In a prospective community-based cohort (Amsterdam Born Children and their Development cohort), women completed questionnaires during pregnancy and at 3-5 months post-delivery regarding self-history of asthma and atopy, and of wheezing of their offspring (n=4860). Pre-pregnancy BMI was recorded and serum total cortisol levels were measured in a subset of women (n=2227) at their first antenatal visit. A total of 20.2% (n=984) women were overweight or obese and 10.3% reported wheezing in their offspring. Maternal BMI was associated with offspring wheezing (1 unit (kg/m2) increase, OR: 1.03; 95% CI: 1.00-1.05), after correction for confounders. Although maternal cortisol levels were lower in overweight mothers and those with a history of asthma, maternal cortisol levels did not mediate the increased offspring wheezing. Pre-pregnancy BMI impacts on baby wheezing, which is not mediated by lower cortisol levels. As the prevalence of obesity in women of child-bearing age is increasing, further studies are needed to investigate modifiable maternal factors to avoid risk of wheezing in young children.

Severe eczema in infancy can predict asthma development. A prospective study to the age of 10 years

BACKGROUND

Children with atopic eczema in infancy often develop allergic rhinoconjunctivitis and asthma, but the term "atopic march" has been questioned as the relations between atopic disorders seem more complicated than one condition progressing into another.

OBJECTIVE

In this prospective multicenter study we followed children with eczema from infancy to the age of 10 years focusing on sensitization to allergens, severity of eczema and development of allergic airway symptoms at 4.5 and 10 years of age.

METHODS

On inclusion, 123 children were examined. Hanifin-Rajka criteria and SCORAD index were used to describe the eczema. Episodes of wheezing were registered, skin prick tests and IgE tests were conducted and questionnaires were filled out. Procedures were repeated at 4.5 and 10 years of age with additional examinations for ARC and asthma.

RESULTS

94 out of 123 completed the entire study. High SCORAD points on inclusion were correlated with the risk of developing ARC, (B = 9.86, P = 0.01) and asthma, (B = 10.17, P = 0.01). For infants with eczema and wheezing at the first visit, the OR for developing asthma was 4.05(P = 0.01). ARC at 4.5 years of age resulted in an OR of 11.28(P = 0.00) for asthma development at 10 years.

CONCLUSION

This study indicates that infant eczema with high SCORAD points is associated with an increased risk of asthma at 10 years of age. Children with eczema and wheezing episodes during infancy are more likely to develop asthma than are infants with eczema alone. Eczema in infancy combined with early onset of ARC seems to indicate a more severe allergic disease, which often leads to asthma development. The progression from eczema in infancy to ARC at an early age and asthma later in childhood shown in this study supports the relevance of the term "atopic march", at least in more severe allergic disease.

Risk factors for non-atopic asthma/wheeze in children and adolescents: a systematic review

Background

The study of non-atopic asthma/wheeze in children separately from atopic asthma is relatively recent. Studies have focused on single risk factors and had inconsistent findings.

Objective

To review evidence on factors associated with non-atopic asthma/wheeze in children and adolescents.

Methods

A review of studies of risk factors for non-atopic asthma/wheeze which had a non-asthmatic comparison group, and assessed atopy by skin-prick test or allergen-specific IgE.

Results

Studies of non-atopic asthma/wheeze used a wide diversity of definitions of asthma/wheeze, comparison groups and methods to assess atopy. Among 30 risk factors evaluated in the 43 studies only 3 (family history of asthma/rhinitis/eczema, dampness/mold in the household, and lower respiratory tract infections in childhood) showed consistent associations with non-atopic asthma/wheeze. No or limited period of breastfeeding was less consistently associated with non-atopic asthma/wheeze. The few studies examining the effects of overweight/obesity and psychological/social factors showed consistent associations. We used a novel graphical presentation of different risk factors for non-atopic asthma/wheeze, allowing a more complete perception of the complex pattern of effects.

Conclusions

More research using standardized methodology is needed on the causes of non-atopic asthma.

Breastfeeding and childhood asthma: systematic review and meta-analysis

Asthma and wheezing disorders are common chronic health problems in childhood. Breastfeeding provides health benefits, but it is not known whether or how breastfeeding decreases the risk of developing asthma. We performed a systematic review and meta-analysis of studies published between 1983 and 2012 on breastfeeding and asthma in children from the general population. We searched the PubMed and Embase databases for cohort, cross-sectional, and case-control studies. We grouped the outcomes into asthma ever, recent asthma, or recent wheezing illness (recent asthma or recent wheeze). Using random-effects meta-analyses, we estimated pooled odds ratios of the association of breastfeeding with the risk for each of these outcomes. We performed meta-regression and stratified meta-analyses. We included 117 of 1,464 titles identified by our search. The pooled odds ratios were 0.78 (95% confidence interval: 0.74, 0.84) for 75 studies analyzing "asthma ever," 0.76 (95% confidence interval: 0.67, 0.86) for 46 studies analyzing "recent asthma," and 0.81 (95% confidence interval: 0.76, 0.87) for 94 studies analyzing recent wheezing illness. After stratification by age, the strong protective association found at ages 0-2 years diminished over time. We found no evidence for differences by study design or study quality or between studies in Western and non-Western countries. A positive association of breastfeeding with reduced asthma/wheezing is supported by the combined evidence of existing studies.

The potential to predict the course of childhood asthma

Many children experience pre-school or early childhood wheezing. In a significant proportion symptoms disappear as the child grows, but others have persistent and troublesome asthma which can be life-long. Tools to predict course of disease in young children are a priority for families and clinicians. This review summarizes evidence from several longitudinal population-based birth-cohort studies that have identified risk factors for persistence and remission of childhood asthma. These factors include clinical characteristics, environmental and other exposures, familial factors, biomarkers of allergic inflammation, measurements of lung function and airway responsiveness, and genetic variants. This review also introduces the concept of polygenic risk and genetic risk scores, and describes results from a recent study that suggests promise for the use of genetic information in predicting the course of childhood asthma. We conclude with a discussion of implications and future directions.

Introduction of complementary foods in infancy and atopic sensitization at the age of 5 years: timing and food diversity in a Finnish birth cohort

OBJECTIVE

To study the associations between timing and diversity of introduction of complementary foods during infancy and atopic sensitization in 5-year-old children.

METHODS

In the Finnish DIPP (type 1 diabetes prediction and prevention) birth cohort (n = 3781), data on the timing of infant feeding were collected up to the age of 2 years and serum IgE antibodies toward four food and four inhalant allergens measured at the age of 5 years. Logistic regression was used for the analyses.

RESULTS

Median duration of exclusive and total breastfeeding was 1.4 (interquartile range: 0.2-3.5) and 7.0 (4.0-11.0) months, respectively. When all the foods were studied together and adjusted for confounders, short duration of breastfeeding decreased the risk of sensitization to birch allergen; introduction of oats <5.1 months and barley <5.5 months decreased the risk of sensitization to wheat and egg allergens, and oats additionally associated with milk, timothy grass, and birch allergens. Introduction of rye <7.0 months decreased the risk of sensitization to birch allergen. Introduction of fish <6 months and egg ≤11 months decreased the risk of sensitization to all the specific allergens studied. The introduction of <3 food items at 3 months was associated with sensitization to wheat, timothy grass, and birch allergens; the introduction of 1-2 food items at 4 months and ≤4 food items at 6 months was associated with all endpoints, but house dust mite. These results were particularly evident among high-risk children when the results were stratified by atopic history, indicating the potential for reverse causality.

CONCLUSIONS

The introduction of complementary foods was consecutively done, and with respect to the timing of each food, early introduction of complementary foods may protect against atopic sensitization in childhood, particularly among high-risk children. Less food diversity as already at 3 months of age may increase the risk of atopic sensitization.

Relevance of birth cohorts to assessment of asthma persistence

The definition of persistent asthma in longitudinal studies reflects symptoms reported at every assessment with no substantive asymptomatic periods. Early-childhood wheezing may be transient, especially if it is of viral etiology. Longitudinal studies provide greater opportunity to confirm the diagnosis by variability of symptoms, objective measurements, and therapeutic responses. Several clinical phenotypes of childhood asthma have been identified, with general consistency between cohorts. Persistent wheezing is often associated with loss of lung function, which is evident from early-childhood and related to persistent inflammation and airway hyperresponsiveness. Female sex, atopy, airway responsiveness, and personal smoking, but not exposure to environmental tobacco smoke, are risk factors for persistence of childhood asthma into adulthood. The effect of breastfeeding remains controversial, but gene-environment interactions may partly explain outcomes. Understanding the natural history and underlying causes of asthma may lead to development of strategies for primary prevention.

Timing of infant feeding in relation to childhood asthma and allergic diseases

BACKGROUND

Emerging evidence questions current recommendations on the timing of infant feeding for the prevention of childhood allergies. The evidence for asthma is inconclusive.

OBJECTIVE

We sought to investigate the associations between the duration of breast-feeding and timing of introduction of complementary foods and the development of asthma and allergies by the age of 5 years.

METHODS

Data were analyzed for 3781 consecutively born children. The dietary exposures were categorized into thirds and analyzed as time-dependent variables. Asthma, allergic rhinitis, and atopic eczema end points were assessed by using the International Study of Asthma and Allergies in Childhood questionnaire, whereas IgE antibodies were analyzed from serum samples at the age of 5 years. Cox proportional hazard and logistic regressions were used for the analyses.

RESULTS

The median duration of exclusive and total breast-feeding was 1.4 months (interquartile range, 0.2-3.5 months) and 7.0 months (interquartile range, 4.0-11.0 months), respectively. Total breast-feeding of 9.5 months or less was associated with an increased risk of nonatopic asthma. Introduction of wheat, rye, oats, or barley at 5 to 5.5 months was inversely associated with asthma and allergic rhinitis, whereas introduction of other cereals at less than 4.5 months increased the risk of atopic eczema. Introduction of egg at 11 months or less was inversely associated with asthma, allergic rhinitis, and atopic sensitization, whereas introduction of fish at 9 months or less was inversely associated with allergic rhinitis and atopic sensitization.

CONCLUSION

Early introduction of wheat, rye, oats, and barley cereals; fish; and egg (respective to the timing of introduction of each food) seems to decrease the risk of asthma, allergic rhinitis, and atopic sensitization in childhood. Longer duration of total breast-feeding, rather than its exclusivity, was protective against the development of nonatopic but not atopic asthma, suggesting a potential differing effect of breast-feeding on different asthma phenotypes.

Breastfeeding is associated with lower risk for multiple sclerosis

Background:

Multiple sclerosis (MS) is an autoimmune disease with known genetic and environmental susceptibility factors. Breastfeeding has been shown to be protective in other autoimmune diseases.

Objective:

This case-control study analyzed the association of breastfeeding in infancy on the risk of developing MS.

Methods:

A case-control study was performed in Berlin of 245 MS patients and 296 population-based controls, who completed a standardized questionnaire on their history and duration of breastfeeding in infancy and demographic characteristics. Univariable and multivariable logistic regression analysis was performed to investigate the association between breastfeeding and MS. The multivariate model was adjusted for age, gender, number of older siblings, number of inhabitants in place of domicile between ages 0 and 6 (categorized in each case), and daycare attendance between ages 0 and 3.

Results:

In multivariable analysis, breastfeeding showed an independent association with MS (adjusted OR 0.58; p = 0.028). However, with no breastfeeding as reference, the protective effect only emerges after four months of breastfeeding (multivariable analysis for ≤ four months adjusted OR 0.87; p = 0.614 and for > four months OR 0.51; p = 0.016).

Conclusion:

The results of this case-control study support the hypothesis that breastfeeding is associated with a lower risk of MS. These results are in line with findings of previous studies on other autoimmune diseases, in which breastfeeding was shown to have protective effects.

Study of wheezing and its risk factors in the first year of life in the Province of Salamanca, Spain. The EISL Study

OBJECTIVES

To determine the prevalence of wheezing and its associated risk factors in infants in the first year of life in the province of Salamanca, Spain.

METHODS

A multicentre, cross-sectional, descriptive epidemiological study was designed to evaluate a representative sample of 750 infants in the first year of life, born in the province of Salamanca between 1 June 2008 and 30 September 2009. The study was based on a previously validated and standardised written questionnaire administered among the parents of those children seen for control at 12 months of age in any of the Primary Care centres in the province of Salamanca.

RESULTS

The recorded wheezing rate was 32.3%. Feeding and sleep were seen to be affected in 46.3% and 80.9% of the wheezing children, respectively, and parent activity was also altered in 39.3% of the cases. A relationship was found between wheezing and nursery attendance (OR: 1.66, 95% confidence interval [1.19-2.31]); weight at birth >3500 g (OR: 1.45 [1.02-2.06]); the presence of eczema at this age (OR: 2.72 [1.75-4.24]); exclusive breastfeeding for <3 months (OR: 1.33 [0.98-1.81]); and maternal smoking during the last three months of pregnancy (OR: 1.60 [0.96-2.68]). The prevalence of recurrent wheezing (defined as three or more episodes) was 11.9%. Significant differences were observed with respect to nursery attendance (OR: 1.71 [1.08-2.72]), the presence of eczema at this age (OR: 2.55 [1.48-4.42]), a history of maternal asthma (OR: 2.19 [1.08-4.44]) and exclusive breastfeeding for <3 months (OR: 1.53 [0.98-2.38]).

CONCLUSIONS

In the province of Salamanca, one third of the infants studied suffered wheezing in the first year of life. Infants exclusively breastfed for less than three months; attending a nursery; having suffered eczema; or with an asthmatic mother showed significantly more wheezing than the rest. Wheezing proved recurrent in 11.9% of the cases.

[Atopic dermatitis and prolonged exclusive breast-feeding]

BACKGROUND

We sought to compare the prevalence of exclusive breastfeeding throughout at least the first 6 months of life in patients presenting atopic dermatitis (AD) with a control group, and to check for a correlation between the duration of exclusive breastfeeding and the severity of AD.

PATIENTS AND METHODS

We conducted a case-control study with prospective inclusion over a period of 3 years. The study group consisted of 114 patients aged less than 15 years, from an urban area, presenting AD but with no personal or family history of atopy. Each patient was compared with two controls from the same town, matched for age and gender, with no personal or family history of atopy, and free of AD. Data analysis was performed using the SPSS software package, version 15.0. A P-value of less than 0.05 was considered as statistically significant.

RESULTS

The prevalence of exclusive breastfeeding for at least the first 6 months of life in the patient group was significantly lower than in the control group (P=0.0413). On the other hand, AD was significantly less severe in patients exclusively breastfed for longer than 9 months (P=0.0079).

CONCLUSION

The correlations recorded in our study do not allow us to draw any definite conclusions about a protective effect of exclusive breastfeeding with regard to AD. However, other benefits of extended exclusive breastfeeding justify supporting breastfeeding in a community with an existing sociocultural predisposition for this feeding method.

Gestational medication use, birth conditions, and early postnatal exposures for childhood asthma

Our aim is to explore (1) whether gestational medication use, mode of delivery, and early postnatal exposure correlate with childhood asthma, (2) the dose responsiveness of such exposure, and (3) their links to early- and late-onset asthma. We conducted a matched case-control study based on the Taiwan Children Health Study, which was a nationwide survey that recruited 12-to-14-year-old school children in 14 communities. 579 mothers of the participants were interviewed by telephone. Exclusive breastfeeding protected children from asthma. Notably, childhood asthma was significantly associated with maternal medication use during pregnancy, vacuum use during vaginal delivery, recurrent respiratory tract infections, hospitalization, main caregiver cared for other children, and early daycare attendance. Exposure to these factors led to dose responsiveness in relationships to asthma. Most of the exposures revealed a greater impact on early-onset asthma, except for vacuum use and daycare attendance.

Global analysis of breast feeding and risk of symptoms of asthma, rhinoconjunctivitis and eczema in 6-7 year old children: ISAAC Phase Three

BACKGROUND

In Phase Three of the International Study of Asthma and Allergies in Childhood (ISAAC), we investigated the relationship between breast feeding in infancy and symptoms of asthma, rhinoconjunctivitis and eczema in 6-7 year old children.

METHODS

Parents or guardians of 6-7 year old children completed written questionnaires on current symptoms of asthma, rhinoconjunctivitis and eczema, and on a range of possible asthma risk factors including a history of breast feeding ever. Prevalence odds ratios were estimated using logistic regression, adjusted for gender, region of the world, language, per capita gross national income, and other risk factors.

RESULTS

In all 206,453 children from 72 centres in 31 countries participated in the study. Reported breast feeding ever was not associated with current wheeze, with an odds ratio (adjusted for gender, region of the world, language, per capita gross national income, and factors encountered in infancy) of 0.99 (95% CI 0.92-1.05), current rhinoconjunctivitis (OR 1.00, 95% CI 0.93-1.08), current eczema (OR 1.05, 95% CI 0.97-1.12), or symptoms of severe asthma (OR 0.95, 95% CI 0.87-1.05). Breast feeding was however associated with a reduced risk of severe rhinoconjunctivitis (OR 0.74, 95% CI 0.59-0.94) and severe eczema (OR 0.79, 95% CI 0.66-0.95).

CONCLUSIONS

There was no consistent association between breast feeding use in the first year of life and either a history or current symptoms of wheezing, rhinoconjunctivitis or eczema in 6-7 year old children, but possibly an effect on severe symptoms of the latter two conditions.

Coenzyme A contained in mothers' milk is associated with the potential to induce atopic dermatitis

T(h)2 adjuvant activity can be qualitatively and quantitatively evaluated using a mixed lymphocyte reaction and by changes in the intracellular cyclic adenosine 3',5'-monophosphate concentration, using human dendritic cells in vitro. The current study shows that mothers, whose children (n = 55) developed atopic dermatitis (AD) within 6 months after birth, often demonstrate a higher T(h)2 adjuvant activity in their milk, in comparison to those whose children did not develop such symptoms. Such an activity was recovered in a liquid phase of mothers' milk and was eluted as a single fraction by reversed-phase HPLC. Further analysis of this fraction by mass spectrometry showed that signals originating from a factor with a molecular weight of 767.53 are observed, exclusively in milk with a high T(h)2 adjuvant activity. The mass is exactly that of Coenzyme A (CoA), and indeed, a low concentration of CoA exhibited T(h)2 adjuvant activity both in vitro and in vivo. Moreover, mesenteric lymph node non-T cells obtained from mice that were orally treated with CoA led allogeneic naive CD4(+) T cells to differentiate into T(h)2. Furthermore, the oral administration of CoA induced rough skin, hyperplasia of the epidermis, hypergranulosis in the spinous layer and the thickening of the stratum in mice. These data collectively indicate that some of the patients with AD were exposed to mothers' milk carrying high T(h)2 adjuvant activity right after birth, which may be attributable to presence of CoA contained in the milk.

Environmental risk factors in the first year of life and childhood asthma in the Central South of Chile

BACKGROUND

Childhood asthma has a high prevalence in South America--a region of the world currently undergoing a thorough modernization and transition process. Asthma in South America is mainly associated with poor urban environment, which actually may challenge the role of the hygiene hypothesis. We systematically assessed the impact of environmental factors in the first year of life on asthma.

METHODS

A case-control study including 188 asthmatics and 294 hospital-based controls aged 6-15 years was carried out in the Central South of Chile. Parents of study participants completed a computer-assisted interview on environmental factors (such as birth order, day-care attendance, pneumonia infection, regular animal and furry pet contact, and environmental tobacco smoke exposure) in the first year of life and potential confounders. Atopy was assessed using skin prick tests. Multivariate logistic regression models were calculated to assess the association between exposures and asthma, adjusting for potential confounders.

RESULTS

Day-care attendance (OR = 0.31; 95% CI: 0.10, 0.94) and regular farm animal contact (OR = 0.38; 95% CI: 0.17, 0.85) were inversely related to childhood asthma in the logistic regression models. Pneumonia infection (OR = 2.24; 95% CI: 1.21, 4.16) and mold or dampness in the home (OR = 1.87; 95% CI: 1.18, 2.97) in the first year of life were positively associated with asthma.

CONCLUSION

Our results suggest that the hygiene hypothesis is also applicable in the Chilean setting, a South American country in epidemiological transition.

Maternal and childhood asthma: risk factors, interactions, and ramifications

Asthma is emerging as a premier example of a health risk that can largely be molded by the status of the mother and the environmental conditions encountered during sensitive windows of prenatal and early childhood development. While genetic background, allergic status of parents, and predisposition for atopy and inflammation play a role, early-life environmental conditions can completely alter the course of immune and respiratory system development. Environmentally induced alterations that (1) maintain the Th2 bias seen during gestation, (2) block the maturation of innate immune cells and (3) create inflammatory dysfunction in the infant provide the foundation for childhood asthma. No single risk factor can fully explain the increased prevalence of asthma in recent decades but it is assumed that the rapid increase is due to environmental and/or epigenetic changes. Well-established and suspected environmental risk factors cover all categories of early life interactions from diet, exposure to environmental contaminants and drugs, maternal and neonatal infections, hygiene, timing of vaccinations and even the mode of birth delivery. Because asthma is connected to the risk of several comorbid chronic conditions, the benefit of asthma risk reduction and prevention is greater than initially may be apparent. This review discusses strategies to optimize preventative and therapeutic options across life stages.

Overweight, asthma symptoms, atopy and pulmonary function in children of 4-12 years of age: findings from the SCAALA cohort in Salvador, Bahia, Brazil

OBJECTIVE

To evaluate the association between overweight and the occurrence of asthma and atopy in a cohort of children of 4-12 years of age living in the city of Salvador in 2005.

DESIGN

Cross-sectional study nested in a cohort.

SETTING

The metropolitan region of Salvador, Bahia, Brazil.

SUBJECTS

The study included 1129 children of 4-12 years age who presented complete information on the variables used here. Skin tests for allergy, spirometry, faecal parasitology, serum IgE and anthropometric surveys were conducted. Poisson's multivariate regression was adopted.

RESULTS

Wheezing was found in 29·1% and asthma in 22·8% of children, both conditions being more common in those under 6 years of age and 34% more common in overweight children (prevalence ratio (PR) = 1·34; 95% CI 1·07, 1·67) following adjustment. The ratio between forced expiratory volume in 1s and forced vital capacity was associated with overweight (PR = 1·35; 95% CI 1·11, 1·61). No statistically significant association was found between overweight and allergen-specific IgE or with wheezing.

CONCLUSIONS

These results are in agreement with the hypothesis that overweight is associated with asthma and pulmonary function, even following adjustment for intervening variables known to be associated with the pathogeny of asthma.

Maternal country of origin, breast milk characteristics and potential influences on immunity in offspring

Breast milk contains pro- and anti-inflammatory cytokines and chemokines with potential to influence immunological maturation in the child. We have shown previously that country of birth is associated with the cytokine/chemokine profile of breast milk. In this study we have investigated how these differences in breast milk affect the cellular response of cord blood mononuclear cells (CBMCs) and intestinal epithelial cells (IECs, cell line HT-29) to microbial challenge. Ninety-five women were included: 30 from Mali in West Africa, 32 Swedish immigrants and 33 native Swedish women. CBMCs or IECs were stimulated in vitro with breast milk, alone or in combination with lipopolysaccharide (LPS) or peptidoglycan (PGN). Breast milk in general abrogated the LPS-induced down-regulation of surface CD14 and Toll-like receptor (TLR)-4 expression on CB monocytes, while inhibiting the PGN-induced TLR-2 up-regulation. However, breast milk from immigrant women together with LPS induced a lower CBMC release of interleukin (IL)-6 (P = 0·034) and CXCL-8/IL-8 (P = 0·037) compared with breast milk from Swedish women, while breast milk from Swedish women and Mali women tended to increase the response. The same pattern of CXCL-8/IL-8 release could be seen after stimulation of IECs (HT-29). The lower CBMC and IEC (HT-29) responses to microbial compounds by breast milk from immigrant women could be explained by the fact that breast milk from the immigrant group showed a divergent pro- and anti-inflammatory content for CXCL-8/IL-8, transforming growth factor-β1 and soluble CD14, compared to the other two groups of women. This may have implications for maturation of their children's immune responses.

Long-term studies of the natural history of asthma in childhood

Segmentation of children with asthma and other wheezy disorders remains the main research challenge today, as it was when described 2 centuries ago. Early childhood wheezy disorders follow different temporal trajectories, probably representing different underlying mechanisms (endophenotypes). Prospective identification of endophenotypes allowing accurate prediction of the clinical course is currently not possible. The variability of the clinical course remains an enigma and difficult to predict. Three of 4 school-aged children with asthma have outgrown disease by midadulthood. The risk of persistence increases with severity, sensitization, smoking, and female sex. Genetic risk variants might help disentangle the heterogeneity of asthma and other wheezy disorders. At early school age, children with asthma have reduced lung function. It is an important and unresolved question whether the airflow limitation associated with asthma already existed at birth or developed along with symptoms. Likewise, the association between the infant's bronchial responsiveness and development of asthma and other wheezy disorders is unclear. Neither primary prevention through manipulation of environmental factors nor secondary prevention through the use of inhaled corticosteroids can effectively halt the long-term disease progression in childhood. In conclusion, the natural history of asthma and the associated airway changes is still poorly understood, and we have not managed to translate findings from long-term studies into a deeper understanding of the underlying endophenotypes or improved disease management. We propose the need for a translational research approach based on long-term clinical studies of birth cohorts with comprehensive and objective assessments of intermediate phenotypes and environmental exposures combined with interdisciplinary basic research and a systems biology approach.

Epidemiology of asthma: risk factors for development

This comprehensive review of the recent literature was undertaken to determine the current state of knowledge of the risk factors involved in the development of asthma in order to focus investigations in a proposed new longitudinal birth cohort study. The origins of asthma appear to lie in the prenatal and early postnatal period, and renewed investigations in this period with long-term close follow-up and objective phenotypic characterization will help to unravel the role of the multiple putative environmental factors in the development of asthma. It is only after understanding these effects that one can hope to design rational prevention studies for asthma.

Breast-feeding in relation to asthma, lung function, and sensitization in young schoolchildren

BACKGROUND

The evidence from previous studies on beneficial effects of breast-feeding in relation to development of asthma is conflicting.

OBJECTIVE

To investigate the relation between breast-feeding and asthma and/or sensitization during the first 8 years of life.

METHOD

In a birth cohort, children were followed up to 8 years by questionnaires at ages 2 months and 1, 2, 4, and 8 years to collect information on exposures and health effects. Determination of serum IgE antibodies to common inhalant and food allergens was performed at 4 and 8 years. Longitudinal analyses were applied by using general estimated equations. The study population consisted of 3825 children (93% of the original cohort), of whom 2370 gave blood and 2564 performed lung function measurements at 8 years.

RESULTS

Children exclusively breast-fed 4 months or more had a reduced risk of asthma during the first 8 years of life (adjusted odds ratio [OR], 0.63; 95% CI, 0.50-0.78) compared with children breast-fed less than 4 months. At 8 years, reduced risks of sensitization (adjusted OR, 0.79; 95% CI, 0.64-0.99) and asthma in combination with sensitization (adjusted OR, 0.59; 95% CI, 0.37-0.93) were seen among children exclusively breast-fed 4 months or more. This group also had a significantly better lung function measured with peak expiratory flow.

CONCLUSION

Breast-feeding for 4 months or more seems to reduce the risk of asthma up to 8 years. At this age, a reduced risk was observed particularly for asthma combined with sensitization. Furthermore, breast-feeding seems to have a beneficial effect on lung function.

Risk for asthma in offspring of asthmatic mothers versus fathers: a meta-analysis

BACKGROUND

Many human epidemiologic studies demonstrate that maternal asthma confers greater risk of asthma to offspring than does paternal disease. However, a handful have shown the opposite. Given this disparity, a meta-analysis is necessary to determine the veracity and magnitude of the "maternal effect."

METHODOLOGY/PRINCIPAL FINDINGS

We screened the medical literature from 1966 to 2009 and performed a meta-analysis to compare the effect of maternal asthma vs. paternal asthma on offspring asthma susceptibility. Aggregating data from 33 studies, the odds ratio for asthma in children of asthmatic mothers compared with non-asthmatic mothers was significantly increased at 3.04 (95% confidence interval: 2.59-3.56). The corresponding odds ratio for asthma in children of asthmatic fathers was increased at 2.44 (2.14-2.79). When comparing the odds ratios, maternal asthma conferred greater risk of disease than did paternal asthma (3.04 vs. 2.44, p = 0.037). When analyzing the studies in which asthma was diagnosed by a physician the odds ratios were attenuated and no significant differences were observed (2.85 vs. 2.48, N = 18, p = 0.37). Similarly, no significant differences were observed between maternal and paternal odds ratios when analyzing the studies in which the patient population was 5 years or older (3.15 vs. 2.60, p = 0.14). However, in all cases the trend remained the same, that maternal asthma was a greater risk factor for asthma than paternal.

CONCLUSIONS/SIGNIFICANCE

The results show that maternal asthma increases offspring disease risk to a greater extent than paternal disease.

Increased risk of eczema but reduced risk of early wheezy disorder from exclusive breast-feeding in high-risk infants

BACKGROUND

Breast-feeding is recommended for the prevention of eczema, asthma, and allergy, particularly in high-risk families, but recent studies have raised concern that this may not protect children and may even increase the risk. However, disease risk, disease manifestation, lifestyle, and the choice to breast-feed are interrelated, and therefore, analyzing true causal effects presents a number of methodologic challenges.

OBJECTIVE

First, to assess the effect from duration of exclusive breast-feeding on the development of eczema and wheezy disorders during the first 2 years of life in a high-risk clinical birth cohort. Second, to assess any influence from the fatty acid composition of mother's milk on the risk from breast-feeding.

METHODS

We studied disease development during the first two years of life of the 411 infants from the Copenhagen Study on Asthma in Childhood (COPSAC) birth cohort, born to mothers with a history of asthma. We analyzed the effect from duration of breast-feeding before disease onset on the disease risk, avoiding the effect from disease-related modification of exposure (inverse causation). Polyunsaturated fatty acids were measured in breast milk.

RESULTS

Breast-feeding significantly increased the risk of eczema adjusted for demographics, filaggrin variants, parents' eczema, and pets at home (N = 306; relative risk, 2.09; 95% CI 1.15-3.80; P = .016) but reduced the risk of wheezy episodes (relative risk, 0.67; 95% CI 0.48-0.96; P = .021) and of severe wheezy exacerbation (relative risk, 0.16; 95% CI 0.03-1.01; P = .051). There was no association between the fatty acid composition of mother's milk and the risk of eczema or wheeze.

CONCLUSION

The risk of eczema was increased in infants with increasing duration of breast-feeding. In contrast, the risk of wheezy disorder and severe wheezy exacerbations was reduced. There were no significant effects from the fatty acid composition of the breast milk on risk of eczema or wheezy disorders.

Breastfeeding is an essential complement to vaccination

AIM

This article explores the role of breastfeeding in different aspects of vaccination in the first 6 months when infants are still developing: (1) pain management; (2) immunomodulation of infants' vaccine responses; (3) metabolism of thimerosal.

METHODS

Major databases were searched for studies that addressed outcomes of related issues.

RESULTS

Studies reveal that breastfeeding can: (1) help mothers and infants to cope with the stressful situations that accompany parenteral vaccines; (2) improve response to vaccines in the still maturing immunologic and enterohepatic systems of infants; (3) influence physiologic parameters that can change metabolism of ethylmercury derived from some vaccines.

CONCLUSION

Health promotion that supports vaccinations should also emphasize early initiation and maintenance of exclusive breastfeeding up until 6 months for maximum protection of the infants with a possible beneficial effect on the vaccine response. Paediatric professionals should inform mothers of the proven benefits of breastfeeding and its importance in complementing vaccination and lowering stress and the risk of untoward reactions on susceptible infants.

Regulatory T cells and asthma

Airway inflammation in asthma is characterized by activation of T helper type-2 (Th2) T cells, IgE production and eosinophilia. In many cases, this process is related to an inappropriate T cell response to environmental allergens, and other T cell-dependent pathways may also be involved (such as Th17). Regulatory T cells (Tregs) are T cells that suppress potentially harmful immune responses. Two major subsets of Treg are CD25(hi), Foxp3(+)Tregs and IL-10-producing Tregs. There is evidence that the numbers or function of both subsets may be deficient in patients with atopic allergic disease. Recent work has extended these findings into the airway in asthma where Foxp3 expression was reduced and CD25(hi) Treg-suppressive function was deficient. In animal models of allergic airways disease, Tregs can suppress established airway inflammation and airway hyperresponsiveness, and protocols to enhance the development, recruitment and function of Tregs have been described. Together with studies of patients and in vitro studies of human T cells, these investigations are defining potential interventions to enhance Treg function in the airway in asthma. Existing therapies including corticosteroids and allergen immunotherapy act on Tregs, in part to increase IL-10 production, while vitamin D3 and long-acting beta-agonists enhance IL-10 Treg function. Other possibilities may be enhancement of Treg function via histamine or prostanoid receptors, or by blocking pro-inflammatory pathways that prevent suppression by Tregs (activation of Toll-like receptors, or production of cytokines such as IL-6 and TNF-alpha). As Tregs can also suppress the potentially beneficial immune response important for controlling infections and cancer, a therapeutic intervention should target allergen- or site-specific regulation.

Atopic dermatitis: a review of recent advances in the field

Atopic dermatitis is increasing in prevalence and currently affects 15–30% of children in urban areas. Immune dysregulation and an impaired epidermal barrier are important factors in the pathogenesis of this disease. Pruritus and a chronic relapsing remitting course are hallmarks of the disorder, and sleep disturbance can occur in both the patient and family. Preventive interventions include exclusive breastfeeding in the first 4 months of life and withholding solid foods for 6 months. The avoidance of irritants and the use of emollients decrease flares. Topical corticosteroids remain the mainstay of therapy, and should be judiciously utilized. Excessive and inappropriate use must be avoided, as well as ‘steroid phobia’. The topical calcineurin inhibitors can be useful adjuncts. Systemic therapies are available for severe disease, but carry risks of adverse effects.