The development and prediction of atopy in high-risk children: follow-up at age seven years in a prospective randomized study of combined maternal and infant food allergen avoidance

IL-4 regulates skin homeostasis and the predisposition toward allergic skin inflammation

IL-4 promotes the development of Th2 cells and allergic inflammation. In atopic dermatitis lesions, IL-4 decreases the expression of multiple genes associated with innate defense, including genes in the epidermal differentiation complex (EDC) that regulate epidermal barrier function. However, it is not clear whether IL-4 also contributes to homeostatic control of EDC genes. In this report, we demonstrate that expression of EDC genes and barrier function is increased in the absence of endogenous IL-4. Mice that express a constitutively active Stat6 (Stat6VT) are prone to the development of allergic skin inflammation and have decreased expression of EDC genes. IL-4 deficiency protects Stat6VT transgenic mice from the development of allergic skin inflammation and decreased recovery time in barrier function following skin irritation, with a concomitant increase in EDC gene expression. These data suggest that IL-4 plays an important role in regulating epidermal homeostasis and innate barrier function.

The association between early sensitization patterns and subsequent allergic disease. The DARC birth cohort study

Prevention of allergic diseases depends on early identification of clinical markers preceding such disorders. This study describes the natural course of sensitization as measured by skin prick test (SPT) and specific immunoglobulin E (S-IgE) and analyses the association between early sensitization patterns and subsequent allergic disease at 6 yr of age. In an ongoing population-based birth cohort study of 562 children, follow-up visits were performed at 0, 3, 6, 9, 12, 18, 36, and 72 months. Visits included an interview, physical examination, SPTs, and S-IgE measurements for 12 food and inhalant allergens. The frequency of S-IgE sensitization to > or = 1 inhalant allergen was constant from 0 to 6 months (9-10%), decreased at 12-18 months before increasing from 36 months onwards. S-IgE sensitization to at least one food allergen remained constant from 0 to 6 yr. SPT sensitization to food and inhalant allergens appeared from 3 and 12 months, respectively. Early food sensitization (S-IgE) between 3 and 18 months was found to be significantly (p < 0.05) associated with atopic dermatitis (OR: 4.0 [1.6-9.9]) and asthma (OR 4.0 [1.1-12.5]) at the age of 6 yr. Children with atopic dermatitis, asthma, or rhinoconjunctivitis, and sensitization at 6 yr, were sensitized to food allergens to a large extent (53%, 42%, and 47%, respectively) already at 6 months. Early inhalant sensitization (S-IgE) did not increase the risk of later allergic disease. Early atopic dermatitis (0-18 months) was also highly associated with subsequent allergic disease. Children with early food sensitization and/or atopic dermatitis would be a proper target group for future interventional studies.

An update on food allergy

PURPOSE OF REVIEW

The present review serves to address food allergy, which is a common problem encountered by the general pediatrician. Between 4 and 6% of US children have an allergic reaction to at least one food, and the prevalence of some food allergies appears to be increasing.

RECENT FINDINGS

A combination of genetic influences, characteristics of food antigen processing, and timing of food introduction may influence the development of food allergy. Avoidance of highly allergenic foods beyond 4-6 months may not be effective at preventing the development of food allergy in most children, and the effect of specific early introduction of allergenic foods is being investigated. Oral immunotherapy is under investigation but may be limited in future use by several factors, including a significant rate of allergic reactions.

SUMMARY

Current management of food allergy focuses on accurate diagnosis, appropriate counseling regarding strict allergen avoidance with review of available educational resources, emergency preparedness, instruction on the use of self-injectable epinephrine, and ongoing surveillance for the possible development of tolerance.

Infant feeding and allergy prevention: a review of current knowledge and recommendations. A EuroPrevall state of the art paper

The relationship between infant feeding patterns and the later development of food allergies has been the focus of much debate and research over the last decade. National recommendations have been made by many countries on how to feed infants to reduce the risk of food allergy but due to the lack of firm evidence the recommendations differ widely. This review has been developed as part of EuroPrevall, a European multicentre research project funded by the European Union, to document the differing feeding recommendations made across Europe, to investigate the current evidence base for any allergy prevention feeding recommendations and to identify areas where further research is needed. This review will also provide information which, when combined with the infant feeding data collected as part of EuroPrevall, will give an indication of compliance to national feeding guidelines which can be utilised to assess the effectiveness of current dissemination and implementation strategies.

The Key Events Dose-Response Framework: a foundation for examining variability in elicitation thresholds for food allergens

Food allergies are caused by immunological reactions in individuals sensitized to normal protein components of foods. For any given sensitized individual, the severity of a reaction is generally assumed to be proportional to the dose of allergenic protein. There is substantial clinical evidence that "threshold" doses exist for the elicitation of an allergic reaction; however, the threshold (i.e., lowest dose that elicits a reaction) varies substantially across the sensitized population. Current approaches to protecting sensitized individuals from exposure to food allergens are highly qualitative (i.e., they rely on food avoidance). The Key Events Dose-Response Framework is an analytical approach for refining understanding of the biological basis of the dose-response. Application of this approach to food allergy provides a foundation for a more rigorous quantitative understanding of variability in allergic response. This study reviews the allergic disease process and the current approaches to identifying thresholds for food allergens. The pathway of key biological events occurring between food intake and allergic response is considered, along with factors that may determine the nature and severity of response to food allergens. Data needs, as well as implications for identifying thresholds, and for characterizing variability in thresholds, are also discussed.

The interaction between early life upper respiratory tract infection and birth during the pollen season on rye-sensitized hay fever and ryegrass sensitization--a birth cohort study

Studies on early life viral respiratory infection and subsequent atopic disease in childhood have conflicting findings. Animal models show that viral respiratory infection in conjunction with allergen presentation can enhance sensitization. This prospective study assesses the influence of an upper respiratory tract infection (URI) in the first month of life and the season of birth on the development of hay fever and ryegrass allergen sensitization in childhood. From a Tasmanian cohort born during 1988 and 1989, a group of 498 children were followed up at 8 yr and another different group of 415 children were followed up at 16 yr. The ryegrass pollen season in Tasmania occurs in November and December. Forty-four (9.6%) children in Follow-up sample 1 and 47 (12.5%) children in Follow-up sample 2 were born in the pollen season. The parental report of an early upper respiratory tract infection (EURI) was documented prospectively by a home interview at 1 month of age (median age 5.1 wk). Sensitization to ryegrass and house dust mite (HDM) was determined at 8 yr of age by skin prick testing and at 16 yr by ImmunoCap. Ryegrass sensitized hay fever was defined as a positive response to a question on hay fever plus the presence of ryegrass allergy. For children tested at age 8 and born in the pollen season, a EURI by postnatal interview was associated with an increased risk of ryegrass sensitization (OR 5.80 95% CI 1.07, 31.31) but not for children with a EURI born outside the pollen season (OR 0.62 95% CI 0.35, 1.08). Similarly, EURI was significantly associated with early onset (< or = 8 yr) ryegrass sensitized hay fever for children born in the pollen season (AOR 4.78 95% CI 1.17, 19.47) but was not associated with early onset ryegrass sensitized hay fever for children born outside the pollen season (AOR 0.76 95% CI 0.43, 1.33). These findings suggest that early life viral URI interacts with ryegrass allergen exposure in the development of ryegrass allergen sensitization and ryegrass sensitized hay fever symptoms.

Skin prick tests and allergy diagnosis

Skin testing remains an essential diagnostic tool in modern allergy practice. A significant variability has been reported regarding technical procedures, interpretation of results and documentation. This review has the aim of consolidating methodological recommendations through a critical analysis on past and recent data. This will allow a better understanding on skin prick test (SPT) history; technique; (contra-) indications; interpretation of results; diagnostic pitfalls; adverse reactions; and variability factors.

Mono and multifaceted inhalant and/or food allergen reduction interventions for preventing asthma in children at high risk of developing asthma

BACKGROUND

Allergen exposure is one of the environmental factors seemingly associated with the development of asthma. If asthma is a multi-factorial disease, it is hypothesised that prevention might only prove effective if most or all relevant environmental factors are simultaneously avoided.

OBJECTIVES

To assess effect(s) of monofaceted and multifaceted interventions compared with control interventions in preventing asthma and asthma symptoms in high risk children.

SEARCH STRATEGY

We searched the Cochrane Airways Trials Register (December 2008).

SELECTION CRITERIA

Randomised controlled trials of allergen exposure reduction for the primary prevention of asthma in children. Interventions were multifaceted (reducing exposure to both inhalant and food allergens) or monofaceted (reducing exposure to either inhalant or food allergens) Follow up had to be from birth (or during pregnancy) up to a minimum of two years of age.

DATA COLLECTION AND ANALYSIS

We included in the analysis studies assessing the primary outcome (current diagnosis: asthma) and/or one of the secondary outcomes (current respiratory symptoms: wheezing, nocturnal coughing and dyspnoea). We pooled multifaceted and monofaceted intervention trials separately. We made an indirect comparison of their effects using tests for interaction to calculate relative odds ratios.

MAIN RESULTS

We included three multifaceted and six monofaceted intervention studies (3271 children). Physician diagnosed asthma in children less than five years, and asthma as defined by respiratory symptoms and lung function criteria in children aged five years and older, both favoured treatment with a multifaceted intervention compared to usual care (< 5 years: odds ratio (OR) 0.72, 95% confidence interval (CI) 0.54 to 0.96, and > 5 years: OR 0.52, 95% CI 0.32 to 0.85). However, there was no significant difference in outcome between monofaceted intervention and control interventions (< 5 years: OR 1.12, 95% CI 0.76 to 1.64, and > 5 years: OR 0.83, 95% CI 0.59 to 1.16). Indirect comparison between these treatments did not demonstrate a significant difference between multiple interventions and mono-interventions in reducing the frequency of asthma diagnosis in children under five years (relative OR 0.64 (95% CI 0.40 to 1.04, P = 0.07) or five years and older (relative OR 0.63, 95% CI 0.35 to 1.13, P = 0.12). There was also no significant difference between either mono- and multifaceted intervention and control in reducing the likelihood of symptoms of nocturnal coughing at follow up. Wheezing, however, showed a significant difference between multifaceted and mono-interventions (relative OR 0.59, 95% CI 0.35 to 0.99, P = 0.04), but the significance was lost when data on treatment only was analysed.

AUTHORS' CONCLUSIONS

The available evidence suggests that the reduction of exposure to multiple allergens compared to usual care reduces the likelihood of a current diagnosis of asthma in children (at ages < 5 years and 5 years and older). Mono-intervention studies have not produced effects which are statistically significant compared with control. In children who are at risk of developing childhood asthma, multifaceted interventions, characterised by dietary allergen reduction and environmental remediation, reduce the odds of a physician diagnosis of asthma later in childhood by half. This translates to a number needed to treat (NNT) of 17. The effect of multi-faceted interventions on parent reported wheeze was inconsistent and had no significant impact on nocturnal coughing or dyspnoea. Data from monofaceted intervention exposed children studies were not significantly different from those of control groups for all outcomes. There remains uncertainty as to whether multiple interventions are more effective than mono-component interventions. The comparisons made were indirect, making the conclusions drawn uncertain. To our knowledge there are no ongoing studies in which both intervention strategies are randomly compared. The findings, however, warrant further direct comparison between multiple- and monofaceted interventions aimed at reducing the prevalence of asthma in children.

What if it is the other way around? Early introduction of peanut and fish seems to be better than avoidance

For many years, the advice to prevent food allergy was to postpone the introduction of allergens like egg, fish and peanut. However, elimination of food allergens during pregnancy and infancy failed to prevent food allergy. Instead, several studies indicate that early introduction of food like fish and peanuts may be beneficial. The most compelling illustration of this has been presented for peanuts. The prevalence of peanut allergy is lower in children in Israel than in the UK, despite introduction of peanut during infancy in Israel. Other studies have reported that early introduction of fish reduced the risk of allergic sensitization and allergic diseases like eczema.

CONCLUSION

Early introduction rather than avoidance may be a better strategy for the prevention of food allergy. The mechanism may be that early introduction of food allergens during infancy might induce tolerance, thereby preventing the development of allergy.

What is "high risk?" a systematic review of atopy risk and implications for primary prevention

Atopic diseases are common and becoming more prevalent. Efforts have focused on primary disease prevention by identifying high-risk children and applying preventative strategies. Our aim was to evaluate methods used to identify high-risk children in atopy prevention studies. A literature search for relevant articles published between 1986 and 2006 was conducted, and all abstracts were reviewed. The search yielded 1,535 publications, 133 were reviewed in detail, and 57 met inclusion criteria. High risk was defined by 30 different methods. First-degree relatives with an atopic disorder were included in all methods, but only three publications used referenced questionnaires to determine this. Less frequently included were cord blood immunoglobulin E measurements and skin prick or radioallergosorbent testing, and 16 methods relied on history alone. Family history was the most common method used to predict high risk of atopic disease in a child, but a minority of studies used a tested questionnaire to determine the presence of atopy in family members. The methods used to identify high-risk children are variable, and the development and widespread use of a validated, practical screening tool is needed.

Parents' smoking habit and prevalence of atopic eczema in 6-7 and 13-14 year-old schoolchildren in Spain. ISAAC phase III

BACKGROUND AND AIMS

Atopic eczema (AE) is the most frequent inflammatory skin disease in childhood in the western world. Several studies have reported a significant increase of prevalence in recent decades and the environmental factors implicated in its aetiology, including environmental tobacco smoke. This study aims to investigate the possible association of AE prevalence in Spanish schoolchildren aged 6-7 and 13-14 years in relation to their parents' smoking habits.

METHODS

We conducted a cross-sectional population-based study with 6-7 year-old (n = 27805) and 13-14 year-old (n = 31235) schoolchildren from 10 Spanish centres. AE prevalence was assessed using the International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire, and the Spanish Academy of Dermatology criteria, used in Spain to diagnose AE.

RESULTS

An association was found in school-children aged 6-7 (adjusted for gender, presence of asthma, presence of rhinitis, siblings and mother's level of education) between AE being clinically diagnosed with the mother's smoking habit (RPRa 1.40, 1.10-1.78) and there being more than 2 smokers at home (RPRa 1.34, 1.01-1.78). Regarding the presence of itchy rash, an association was observed with fathers who smoke (RPRa 1.40, 1.13-1.72). Among the 13-14 year-olds, no association was observed in relation to either clinically diagnosed AE or the appearance of itchy rash with parents' smoking habit.

CONCLUSIONS

Our results indicate the risk for children of being exposed to environmental tobacco smoke in terms of AE, especially when they are younger.

Food allergy is associated with an increased risk of asthma

BACKGROUND

The atopic march is well documented, but the interrelationship of food allergy (FA) and asthma is not well understood.

OBJECTIVE

The aim of this study was to examine the strength of the association and temporal relationships between FA and asthma.

METHODS

This analysis included 271 children >or=6 years (older group) and 296 children <6 years (younger group) from a family-based FA cohort in Chicago, IL. Asthma was determined by parental report of physician diagnosis. FA status was determined based on the type and timing of clinical symptoms after ingestion of a specific food, and results of prick skin test (Multi-Test II) and allergen-specific IgE (Phadia ImmunoCAP). Analyses were carried out using logistic regression accounting for important covariates and auto-correlations among siblings. Kaplan-Meier curves were used to compare the time to onset of asthma with the FA status.

RESULTS

Symptomatic FA was associated with asthma in both older [odds ratio (OR)=4.9, 95% confidence interval (CI): 2.5-9.5] and younger children (OR=5.3, 95% CI: 1.7-16.2). The association was stronger among children with multiple or severe food allergies, especially in older children. Children with FA developed asthma earlier and at higher prevalence than children without FA (Cox proportional hazard ratio=3.7, 95% CI: 2.2-6.3 for children >or=6 years, and hazard ratio=3.3, 95% CI: 1.1-10 for children <6 years of age). No associations were seen between asymptomatic food sensitization and asthma.

CONCLUSIONS

Independent of markers of atopy such as aeroallergen sensitization and family history of asthma, there was a significant association between FA and asthma. This association was even stronger in subjects with multiple food allergies or severe FA.

Household peanut consumption as a risk factor for the development of peanut allergy

BACKGROUND

Most children with peanut allergy (PA) react on first known oral exposure to peanut. Recent data suggest cutaneous exposure as a route of sensitization.

OBJECTIVES

This study aimed to establish the relevant route of peanut exposure in the development of allergy.

METHODS

Questionnaires were administered to children with PA and to high-risk controls (with egg allergy) and controls without allergy. Questionnaires were completed before subjects were aware of their PA status, avoiding recall bias. Questionnaires recorded maternal peanut consumption during pregnancy, breast-feeding, and the first year of life. Peanut consumption was determined among all household members, allowing quantification of environmental household exposure (household peanut).

RESULTS

Median weekly household peanut in the 133 PA cases was significantly elevated (18.8 g) compared with 150 controls without allergy (6.9 g) and 160 high-risk controls (1.9 g). There were no differences in infant peanut consumption between groups. Differences in maternal peanut consumption during pregnancy (and lactation) were significant but become nonsignificant after adjusting for household peanut. A dose-response relationship was observed between environmental (nonoral) peanut exposure and the development of PA, which was strongest for peanut butter. Early oral exposure to peanut in infants with high environmental peanut exposure may have had a protective effect against the development of PA.

CONCLUSIONS

High levels of environmental exposure to peanut during infancy appear to promote sensitization, whereas low levels may be protective in atopic children. No effect of maternal peanut consumption during pregnancy or lactation is observed, supporting the hypothesis that peanut sensitization occurs as a result of environmental exposure.

The parent-reported prevalence and management of peanut and nut allergy in school children in the Australian Capital Territory

AIM

To describe parent-reported prevalence and management of peanut and nut allergy in school entrant children.

METHOD

A population-based, cross-sectional study in the Australian National Capital.

RESULTS

Out of 3851 children, parents reported 127 had a strong allergic reaction to peanuts and 19 to other nuts ever. Nut allergy ever prevalence was 3.8% (95% confidence interval 3.2-4.4%), and of peanut allergy ever 3.3% (2.8-3.9%). Children with nut allergy were more likely to have a general practitioner (odds ratio 2.64, 1.16-6.03), hay fever (3.78, 2.67-5.36), eczema (4.54, 3.15-6.56) and wheeze in the last 12 months (3.19, 2.22-4.59) and have been breastfed (2.68, 1.26-5.77) than those who did not. At follow up of 109 children with parent-reported allergy (75% response), 70% had diagnostic test-confirmed sensitisation, 32% had been prescribed an adrenalin autoinjector (6% had used one) and 46% were not eating peanut. Increasing severity of reported symptoms following consumption of peanut was associated with an increasing likelihood of recommended management. Based on parent report, the projected estimated diagnostic test-confirmed prevalence of peanut sensitisation was 2.4% (1.9%, 3.0%) for the entire sample.

CONCLUSION

Among a highly representative sample of children at school entry, 1 in 30 parents reported their child to have a strong allergic reaction to nuts and over 1 in 50 are estimated to have diagnostic test-confirmed peanut sensitisation, based on parent report.

Early consumption of peanuts in infancy is associated with a low prevalence of peanut allergy

BACKGROUND

Despite guidelines recommending avoidance of peanuts during infancy in the United Kingdom (UK), Australia, and, until recently, North America, peanut allergy (PA) continues to increase in these countries.

OBJECTIVE

We sought to determine the prevalence of PA among Israeli and UK Jewish children and evaluate the relationship of PA to infant and maternal peanut consumption.

METHODS

A clinically validated questionnaire determined the prevalence of PA among Jewish schoolchildren (5171 in the UK and 5615 in Israel). A second validated questionnaire assessed peanut consumption and weaning in Jewish infants (77 in the UK and 99 in Israel).

RESULTS

The prevalence of PA in the UK was 1.85%, and the prevalence in Israel was 0.17% (P < .001). Despite accounting for atopy, the adjusted risk ratio for PA between countries was 9.8 (95% CI, 3.1-30.5) in primary school children. Peanut is introduced earlier and is eaten more frequently and in larger quantities in Israel than in the UK. The median monthly consumption of peanut in Israeli infants aged 8 to 14 months is 7.1 g of peanut protein, and it is 0 g in the UK (P < .001). The median number of times peanut is eaten per month was 8 in Israel and 0 in the UK (P < .0001).

CONCLUSIONS

We demonstrate that Jewish children in the UK have a prevalence of PA that is 10-fold higher than that of Jewish children in Israel. This difference is not accounted for by differences in atopy, social class, genetic background, or peanut allergenicity. Israeli infants consume peanut in high quantities in the first year of life, whereas UK infants avoid peanuts. These findings raise the question of whether early introduction of peanut during infancy, rather than avoidance, will prevent the development of PA.

Food allergy as seen by an allergist

The clinical expression of allergic disease is the consequence of a series of complex gene-environment interactions that occur at the materno-fetal interface and throughout infancy, leading to persistence of the Th2 immune response. It has been proposed that atopic eczema is the cutaneous manifestation of a systemic disorder that also gives rise to asthma, food allergy, and allergic rhinitis. The recent emergence of genes regulating epidermal barrier function has raised the question of whether the skin barrier in atopic eczema is defective from the outset, rendering the epidermis "leaky," thereby increasing the risk of allergen penetration and the succeeding inflammatory reaction that contributes to atopic eczema. Food allergic sensitisation and eczema frequently coexist during the first 2 years of life, and food allergy is more prevalent in infants and children with moderate to severe eczematous inflammation. The majority of food allergic reactions are caused by 8 foods, with milk, egg, and peanut occurring with greatest frequency. The acquisition of food-specific tolerance occurs predominantly with foods in which the epitopes are grouped together in a conformational structure (milk, egg, wheat, soy), whilst it rarely occurs in patients allergic to foods in which the epitopes are arranged in a linear fashion (nuts, seeds, fish). Better tests and novel therapies, such as immunotherapy and oral tolerance induction, are required for the management of food allergy.

Expired nitric oxide and airway reactivity in infants at risk for asthma

BACKGROUND

Family histories of atopy, as well as histories of atopic dermatitis and food allergy, are important risk factors for an infant to have asthma. Although atopic sensitization appears to contribute to the development of asthma, it is unclear when the airways become involved with the atopic process and whether airway function relates to the atopic characteristics of the infant.

OBJECTIVE

We sought to evaluate whether atopic infants without prior episodes of wheezing have increased expired nitric oxide (eNO) levels and heightened airway reactivity.

METHODS

Infants with eczema were recruited, and atopic status was defined by specific IgE levels to foods or aeroallergens and total IgE levels. eNO, forced expiratory flow at 75% exhaled volume (FEF(75)), and airway reactivity to inhaled methacholine were measured in sedated infants. Airway reactivity was quantified by using the provocative concentration to decrease FEF(75) by 30%.

RESULTS

Median age for the 114 infants evaluated was 10.7 months (range, 2.6-19.1 months). Infants sensitized to egg or milk compared with infants sensitized to neither egg nor milk had lower flows (FEF(75): 336 vs 285 mL/s, P < .003) and lower lnPC(30) (mg/mL) provocative concentrations to decrease FEF(75) by 30% (-0.6 vs -1.2, P < .02) but no difference in eNO levels. Infants with total serum IgE levels of greater than 20 IU/mL had higher eNO levels compared with infants with IgE levels of 20 IU/mL or less (14.6 vs 11.2 ppb, P < .023) but no difference in forced flows or airway reactivity.

CONCLUSIONS

Our findings suggest that atopic characteristics of the infant might be important determinants of the airway physiology of forced expiratory flows, airway reactivity, and eNO.

Food allergy overview in children

Food allergies have increased significantly in the past decade. An accurate history is crucial in approaching the management. At the outset, food intolerance must be distinguished from food allergies and, furthermore, these allergies should be classified into either an IgE, Non-IgE, or a mixed response. The clinical features vary from life-threatening anaphylaxis to milder IgE-mediated responses, atopic dermatitis, and gastrointestinal symptoms. The severity of the reaction and the potential risk for anaphylaxis on reexposure should be assessed. Milk, soy, egg, wheat, and peanut allergies are common in children, whereas peanut, tree nut, fish, shell fish allergies, and allergies to fruits and vegetables are common in adults. Structural proteins are important determinants of the severity of the reactions and may often predict the natural history and cross reactivity. Diagnostic work up must be guided by the clinical history. Skin testing and food-specific IgE done by standard methods are very useful, whereas oral challenges may be indicated in some situations. Majority of the patients outgrow their allergies to milk, soy, egg, and wheat, and some to peanut also, therefore, patients should be periodically reassessed. Novel diagnostic techniques which detect specific allergenic epitopes have been developed. Several newer therapies are promising.

The importance of early complementary feeding in the development of oral tolerance: concerns and controversies

Rising rates of food allergies in early childhood reflect increasing failure of early immune tolerance mechanisms. There is mounting concern that the current recommended practice of delaying complementary foods until 6 months of age may increase, rather than decrease, the risk of immune disorders. Tolerance to food allergens appears to be driven by regular, early exposure to these proteins during a 'critical early window' of development. Although the timing of this window is not clear in humans, current evidence suggests that this is most likely to be between 4 and 6 months of life and that delayed exposure beyond this period may increase the risk of food allergy, coeliac disease and islet cell autoimmunity. There is also evidence that other factors such as favourable colonization and continued breastfeeding promote tolerance and have protective effects during this period when complementary feeding is initiated. This discussion paper explores the basis for concern over the current recommendation to delay complementary foods as an approach to preventing allergic disease. It will also examine the growing case for introducing complementary foods from around 4 months of age and maintaining breastfeeding during this early feeding period, for at least 6 months if possible.

Epidemiologic risks for food allergy

This article reviews possible risk factors and theories for the development of food allergy. It is noted that previous strategies to prevent food allergy through allergen avoidance during pregnancy, breast-feeding, and infancy have more recently been called into question. Alternative hypotheses are examined with respect to food allergy, namely the hygiene hypothesis, the dietary fat hypothesis, the antioxidant hypothesis, and the vitamin D hypotheses. An alternative hypothesis is proposed, suggesting that sensitization to allergen occurs through environmental exposure to allergen through the skin and that consumption of food allergen induces oral tolerance. This hypothesis provides a possible explanation for the close link between eczema and the development of food allergies. It also suggests novel interventional strategies to prevent the development of food allergies.

[Epidemiology of allergic respiratory disorders in infants]

INTRODUCTION

Allergic disorders of the respiratory tract have been the subject of many epidemiological studies, especially during infancy which is known to be a critical period for development of the immune system. This paper aims to describe the prevalence of allergic respiratory disorders in children below three years of age in the general population, despite the lack of shared definition of asthma and allergic rhinitis among studies.

STATE OF ART

Doctor-diagnosed asthma occurs in 5% of children below two years of age. One third of children below three years of age experience wheeze during a lower respiratory tract infection, but only 7% of children wheeze apart from a respiratory infection. Asthma-like cough and bronchial obstruction symptoms are reported in respectively 15% and 9% of children below two years of age. Depending on the definition of allergic rhinitis used, its prevalence varies from 1 to 30% among two years old children.

PERSPECTIVES

Definitions of allergic respiratory tract disorders in infants become more elaborate involving parental and personal history of allergy and medication; epidemiological research now attempts to identify, using biological evidence of atopy, infants at risk of persistent allergic disorders.

CONCLUSIONS

A better definition of allergic respiratory disorders in infants may help epidemiological research and early care management.

Natural history of asthma: persistence versus progression-does the beginning predict the end?

Environmental exposures during the early years and airway obstruction that develops during this time, in conjunction with genetic susceptibility, are important factors in the development of persistent asthma in childhood. Established risk factors for childhood asthma include frequent wheezing during the first 3 years, a parental history of asthma, a history of eczema, allergic rhinitis, wheezing apart from colds, and peripheral blood eosinophilia, as well as allergic sensitization to aeroallergens and certain foods. Risk factors for the development of asthma in adulthood remain ill defined. Moreover, reasons for variability in the clinical course of asthma--persistence in some individuals and progression in others--remain an enigma. The distinction between disease persistence and disease progression suggests that these are different entities or phenotypes. There is currently no consensus on whether disease progression requires either airway inflammation or airway remodeling or the combination of the two. For patients with irreversible airway obstruction, inflammation might, in part, be necessary but perhaps not entirely sufficient to induce the irreversible component, some of which could be attributed to alterations in the structure of the bronchial wall. Intervening with intermittent or daily inhaled corticosteroids in high-risk infants and children does not prevent disease progression or impaired lung growth. These findings, however, might not apply to adults, and further study in adults is needed to determine the effect of inhaled corticosteroid therapy on disease progression.

[Cow milk protein allergies: primary prevention. Nutritional aspects]

In 2001 the Nutrition Committee of the Spanish Association of Pediatrics, published a position paper on "Recommendations on the use of formulae for the treatment and prevention of adverse reactions to cow milk proteins" (An Esp Pediatr. 2001;54:372-9). Since most of the recommendations given in this report still remain effective, the Nutrition Committee of the Spanish Association of Pediatrics reaffirms its support of the data expressed in it. In the present publication we only approach the aspects that have changed due to new knowledge and the accumulated clinical experience, especially on the primary prevention of allergy to cow milk proteins, and on the basis of it, the present recommendations for this prevention are set out. In addition, the importance of the nutritional aspects in all infants and small children receiving special nutritional formulae and exclusion diets are reviewed.

Dietary exclusions for established atopic eczema

BACKGROUND

Atopic eczema (AE) is a non-infective chronic inflammatory skin disease characterised by an itchy red rash.

OBJECTIVES

To assess the effects of dietary exclusions for the treatment of established atopic eczema.

SEARCH STRATEGY

We searched The Cochrane Skin Group Specialised Register (to March 2006), The Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library (Issue 1, 2006), MEDLINE (2003 to March 2006), EMBASE (2003 to March 2006), LILACS (to March 2006), PsycINFO (1806 to March 2006), AMED (1985 to March 2006), ISI Web of Science (March 2006), www.controlled-trials.com, www.clinicaltrials.gov and www.nottingham.ac.uk/ongoingskintrials (March 2006). Pharmaceutical companies were contacted where appropriate for reviews or unpublished trials.

SELECTION CRITERIA

People who have atopic eczema as diagnosed by a doctor.

DATA COLLECTION AND ANALYSIS

Two independent authors carried out study selection and assessment of methodological quality.

MAIN RESULTS

We found 9 RCTs involving a total of 421 participants of which 6 were studies of egg and milk exclusion (N=288), 1 was a study of few foods (N=85) and 2 were studies of an elemental diet (N=48). There appears to be no benefit of an egg and milk free diet in unselected participants with atopic eczema. There is also no evidence of benefit in the use of an elemental or few-foods diet in unselected cases of atopic eczema. There may be some benefit in using an egg-free diet in infants with suspected egg allergy who have positive specific IgE to eggs - one study found 51% of the children had a significant improvement in body surface area with the exclusion diet compared to normal diet (RR 1.51, 95% CI 1.07 to 2.11) and change in surface area and severity score was significantly improved in the exclusion diet compared to the normal diet at the end of 6 weeks (MD 5.50,95% CI 0.19 to 10.81) and end of treatment (MD 6.10, 95% CI 0.06 to12.14). Methodological difficulties have made it difficult to interpret these studies. Poor concealment of randomisation allocation, lack of blinding and high dropout rates without an intention-to-treat analysis indicates that these studies should be interpreted with great caution.

AUTHORS' CONCLUSIONS

There may be some benefit in using an egg-free diet in infants with suspected egg allergy who have positive specific IgE to eggs. Little evidence supports the use of various exclusion diets in unselected people with atopic eczema, but that may be because they were not allergic to those substances in the first place. Lack of any benefit may also be because the studies were too small and poorly reported. Future studies should be appropriately powered focusing on participants with a proven food allergy. In addition a distinction should be made between young children whose food allergies improve with time and older children/adults.

Effects of early nutritional interventions on the development of atopic disease in infants and children: the role of maternal dietary restriction, breastfeeding, timing of introduction of complementary foods, and hydrolyzed formulas

This clinical report reviews the nutritional options during pregnancy, lactation, and the first year of life that may affect the development of atopic disease (atopic dermatitis, asthma, food allergy) in early life. It replaces an earlier policy statement from the American Academy of Pediatrics that addressed the use of hypoallergenic infant formulas and included provisional recommendations for dietary management for the prevention of atopic disease. The documented benefits of nutritional intervention that may prevent or delay the onset of atopic disease are largely limited to infants at high risk of developing allergy (ie, infants with at least 1 first-degree relative [parent or sibling] with allergic disease). Current evidence does not support a major role for maternal dietary restrictions during pregnancy or lactation. There is evidence that breastfeeding for at least 4 months, compared with feeding formula made with intact cow milk protein, prevents or delays the occurrence of atopic dermatitis, cow milk allergy, and wheezing in early childhood. In studies of infants at high risk of atopy and who are not exclusively breastfed for 4 to 6 months, there is modest evidence that the onset of atopic disease may be delayed or prevented by the use of hydrolyzed formulas compared with formula made with intact cow milk protein, particularly for atopic dermatitis. Comparative studies of the various hydrolyzed formulas also indicate that not all formulas have the same protective benefit. There is also little evidence that delaying the timing of the introduction of complementary foods beyond 4 to 6 months of age prevents the occurrence of atopic disease. At present, there are insufficient data to document a protective effect of any dietary intervention beyond 4 to 6 months of age for the development of atopic disease.

The role of atopic sensitization in flexural eczema: findings from the International Study of Asthma and Allergies in Childhood Phase Two

BACKGROUND

The association between allergic sensitization and eczema has been debated for years.

OBJECTIVE

We sought to determine and compare the strength of the association between allergen skin sensitization and eczema in both developing and industrialized countries.

METHODS

Twenty-eight thousand five hundred ninety-one randomly selected 8- to 12-year-old schoolchildren in 20 countries were physically examined for flexural eczema and received skin prick testing to Dermatophagoides pteronyssinus, Dermatophagoides farinae, cat hair, Alternaria tenuis, mixed tree and grass pollen, and allergens of local relevance.

RESULTS

The age- and sex-adjusted odds ratios (ORs) for a positive association between flexural eczema and atopy ranged between 0.74 (95% CI, 0.31-1.81) and 4.53 (95% CI, 1.72-11.93), with a significantly stronger association in affluent compared with nonaffluent countries (combined age- and sex-adjusted OR(affluent) = 2.69 [95% CI, 2.31-3.13] and OR(nonaffluent) = 1.17 [95% CI, 0.81-1.70]). The combined population attributable fraction for atopy in flexural eczema was 27.9% for affluent and 1.2% for nonaffluent-country centers. Correlating gross national per-capita income with either ORs or population attributable fractions for atopy in flexural eczema confirmed a highly significant positive association (P = .006 and P < .001, respectively).

CONCLUSIONS

The association between atopy and flexural eczema is weak and more variable than previously suggested, and the strength of this association is positively linked to gross national income.

Developing asthma in childhood from exposure to secondhand tobacco smoke: insights from a meta-regression

OBJECTIVE

Studies have identified associations between household secondhand tobacco smoke (SHS) exposure and induction of childhood asthma. However, the true nature and strength of this association remains confounded in many studies, producing inconsistent evidence. To look for sources of potential bias and try to uncover consistent patterns of relative risk estimates (RRs), we conducted a meta-analysis of studies published between 1970 and 2005.

DATA SOURCES

Through an extensive literature search, we identified 38 epidemiologic studies of SHS exposure and the development of childhood asthma (that also controlled for atopy history) from 300 potentially relevant articles.

DATA SYNTHESIS

We observed substantial heterogeneity within initial summary RRs of 1.48 [95% confidence interval (CI), 1.32-1.65], 1.25 (1.21-1.30), and 1.21 (1.08-1.36), for ever, current, and incident asthma, respectively. Lack of control for type of atopy history (familial or child) and child's own smoking status within studies and age category altered summary RRs in separate meta-regressions. After adjusting for these confounding characteristics, consistent patterns of association emerged between SHS exposure and childhood asthma induction. Our summary RR of 1.33 (95% CI, 1.14-1.56) from studies of incident asthma among older children (6-18 years of age) is 1.27 times the estimate from studies of younger children and higher than estimates reported in earlier meta-analyses.

CONCLUSIONS

This new finding indicates that exposure duration may be a more important factor in the induction of asthma than previously understood, and suggests that SHS could be a more fundamental and widespread cause of childhood asthma than some previous meta-analyses have indicated.

Solid food introduction in relation to eczema: results from a four-year prospective birth cohort study

OBJECTIVE

To assess the association between the introduction of solid foods in the first 12 months and the occurrence of eczema during the first 4 years of life in a prospective study of newborns.

STUDY DESIGN

Data were taken from annually administered questionnaires from a large birth cohort (recruited 1995-1998) comprised of an intervention and a nonintervention group. Outcomes were doctor-diagnosed and symptomatic eczema. Multiple generalized estimation equation models were performed for the 2 study groups.

RESULTS

From the 5991 recruited infants, 4753 (79%) were followed up. The 2 study groups were different in their family risk of allergies and feeding practices. No association was found between the time of introduction of solids or the diversity of solids and eczema. In the nonintervention group, a decreased risk was observed for avoidance of soybean/nuts, but an increased risk was seen in doctor-diagnosed eczema for the avoidance of egg in the first year.

CONCLUSION

The evidence from this study supports neither a delayed introduction of solids beyond the fourth month nor a delayed introduction of the most potentially allergenic solids beyond the sixth month of life for the prevention of eczema. However, effects under more extreme conditions cannot be ruled out.

Aeroallergen sensitization rates in military children with rhinitis symptoms

BACKGROUND

Childhood sensitization rates for many aeroallergens are underreported.

OBJECTIVES

To examine aeroallergen sensitization rates in military children undergoing skin testing for rhinitis and investigate the timing of atopic development for perennial and seasonal allergens.

METHODS

A skin testing database was retrospectively analyzed. Children 18 years and younger referred for rhinitis underwent skin prick testing to either a screening panel of 8 tests or a standard panel of 51 allergens.

RESULTS

A total of 209 patients underwent skin testing to the 8-test panel. Of these patients, 35.4% had at least 1 positive result. Atopy increased with age, from 6.3% in those younger than 1 year to 58.8% in those 5 years old. The most common allergens were mold mix (16.3%), cat (13.2%), dust mite mix (11.4%), tree mix (9.4%), and grass mix (9.4%). Only 4.0% were sensitized to seasonal aeroallergens before the age of 3 years. A total of 345 children underwent testing to a 51-allergen panel. A total of 80.3% had at least 1 positive test result, and the average number of positive test results was 11.4. Both the percentage of atopy and the average number of positive skin test results increased with age. The most common allergens were grasses, Alternaria, and cottonwood. Thirty-two of 51 allergens were positive in 20% or more children. Rates for many underreported allergens are presented.

CONCLUSIONS

In children, aeroallergen sensitization rates are high and increase with age. Perennial allergens predominate up to the age of 3 years. Rates for many underreported allergens are presented. Although performed in a military population, these results should be applicable to many practices.

WITHDRAWN: Cow's milk protein avoidance and development of childhood wheeze in children with a family history of atopy

BACKGROUND

In infants with a family history of atopy, food allergen avoidance has been advocated as means of preventing the development of atopic disease, when breast-feeding is not possible or supplemental feeding is needed. Most infant formulas are based on cow's milk protein. Alternative choices include soya based and hydrolysed cows milk formulas.

OBJECTIVES

To estimate the effect of dietary avoidance of cow's milk protein on the development of asthma or wheeze in children.

SEARCH STRATEGY

We searched the Cochrane database for eligible trials until February 2002. We obtained the full text papers of all abstracts identified as RCTs and two reviewers independently reviewed them.

SELECTION CRITERIA

We included randomised controlled trials involving children with a family history of atopy in at least one first degree relative, if feeding with cow's milk based standard formula was compared to dietary avoidance of cow's milk protein, using soya or other hypoallergenic formula during the initial four months of life or longer.

DATA COLLECTION AND ANALYSIS

Two reviewers extracted data independently. A priori defined subgroups were the types of hypoallergenic artificial feed and dietary restrictions on mother and/or child's diet.

MAIN RESULTS

Six trials used hydrolysed formula for at least four months, in addition to dietary restrictions and in some cases dust-mite reduction measures. The risk of infants experiencing asthma or wheeze during the first year of life was reduced compared to standard cow's milk based formula (Relative Risk 0.40, 95% Confidence Intervals 0.19 to 0.85). Feeding soya-based formula as opposed to standard cow's milk formula did not reduce the risk of having asthma or wheeze at any age.

AUTHORS' CONCLUSIONS

Breast-milk should remain the feed of choice for all babies. In infants with at least one first degree relative with atopy, hydrolysed formula for a minimum of four months combined with dietary restrictions and environment measures may reduce the risk of developing asthma or wheeze in the first year of life. There is insufficient evidence to suggest that soya-based milk formula has any benefit.

Cow's milk exposure and asthma in a newborn cohort: repeated ascertainment indicates reverse causation

The effect of cow's milk consumption on childhood asthma has been debated for several years. This study attempts to provide further insight into this association through the use of a longitudinal study design. Newborns from parents with atopic history were recruited from Germany, Austria, and England (n = 696). For five repeated ascertainments, information was collected on cow's milk exposure, incidence of doctor-diagnosed asthma, and confounders. Generalized estimation equations, incorporating different models (concurrent, delayed, combined, and reverse causation), were used to determine this association. No association between cow's milk consumption and childhood asthma was found for the concurrent effects model (OR = 0.81, 95% confidence interval [CI]: 0.55, 1.20). In the delayed effects model, the direction of the association varied with time of follow-up. Thus, we stratified by period, which resulted in a significant protective delayed effect at 36 months (OR = 0.18, 95% CI = 0.06, 0.49). However, reverse causation negated this finding since the presence of asthma in prior months led to a reduction in further exposure to cow's milk (OR = 0.40, 95% CI = 0.16, 0.99). Hence, cow's milk consumption does not protect against childhood asthma. The apparent protection of cow's milk against asthma may result from parents of asthmatic children avoiding cow's milk, rather than actual prophylaxis.

Prenatal versus postnatal sensitization to environmental allergens in a high-risk birth cohort

BACKGROUND

The timing of allergen sensitization is controversial, with conflicting evidence suggesting transplacental priming versus exclusively postnatal priming. Resolution of this question is important in relation to rational design of allergy prevention strategies, particularly the issue of allergen avoidance during pregnancy.

OBJECTIVE

To elucidate the kinetics of sensitization in high-risk children during their first 2 years of life.

METHODS

We prospectively studied house dust mite (HDM)-specific IgE and IgG(4) antibody production and associated T-cell immunity in a cohort of 200 high-risk infants. Parallel antibody studies tracked responses against a broader panel of inhalant and dietary allergens including peanut.

RESULTS

HDM-induced T(H)2 responses in PBMC from 6 months onward, particularly IL-4 and IL-5, correlated increasingly strongly with sensitization outcomes at 2 years, and a contrasting negative relationship was observed with IFN-gamma response capacity. HDM-induced T-cell responses in cord blood, although common, were unrelated to subsequent sensitization. Transient HDM-IgE (and IgG(4)) production frequently peaked at 6 or 12 months before returning to baseline, which suggests the onset of protective tolerance. This finding contrasted with progressively increasing HDM-IgE titers in children sensitized by 2 years of age. Comparably contrasting patterns were observed in peanut-specific responses in sensitized versus nonsensitized children.

CONCLUSION

Priming of T(H)2 responses associated with persistent HDM-IgE production occurs entirely postnatally, as HDM reactivity in cord blood seems nonspecific and is unrelated to subsequent development of allergen-specific T(H)2 memory or IgE.

CLINICAL IMPLICATIONS

These findings question the scientific basis for existing recommendations for allergen avoidance by high-risk women during pregnancy.

Is there any role for allergen avoidance in the primary prevention of childhood asthma?

In this article we discuss 3 hypotheses to attempt to understand why preventive measures thus far studied with the aim of preventing (or delaying) the development of asthma have shown such disappointing results. The most likely explanation is that the development of a multifactorial disease, such as asthma, is extremely difficult, if not impossible, to prevent by eliminating only one risk factor. In a meta-analysis we investigated the effect of a multifaceted and monofaceted intervention in 10 prospective birth cohorts of a total of 3473 children on a diagnosis of asthma. Multifaceted intervention studies had an odds ratio (OR) of 0.73 (95% CI, 0.55-0.97), whereas the monointervention studies had an OR of 1.22 (95% CI, 0.83-1.78) in patients younger than 5 years and an OR of 0.52 (95% CI, 0.32-0.84) versus 0.93 (95% CI, 0.66-1.31) in patients older than 5 years. We therefore hypothesize that studies with a multifaceted approach will have a much greater chance of being successful than studies using a monofaceted approach, with the latter being unlikely to yield a clinically relevant reduction of asthma.

Effect of cosensitization with buckwheat flour extract on the production of house dust mite-specific IgE

There are studies reporting food sensitization in infancy increases the risk of sensitization to inhalants later in life. We performed a study to evaluate whether cosensitization with buckwheat (BW) has an effect on the production of house dust mite-IgE. C3H/HeJ mice (4 weeks, female) were sensitized with house dust mite (HDM)/Al (OH)(3), intraperitoneally on day 0, followed by 4 intranasal sensitizations (on days 14, 15, 16, and 21). Group 1 was cosensitized intragastrically with BW/cholera toxin (CT) (on days 0, 1, 2, 7, and 18) during sensitization with HDM, group 2 was cosensitized intragastrically with CT only (on days 0, 1, 2, 7, and 18), and group 3 was used as controls. HDM- and BW-IgE and antigen-specific T-cell proliferation and cytokine production were evaluated. In Group 1, BW-IgE levels were highest at week 4, and the HDM-IgE at week 3 (98.45+/-64.37 ng/mL and 169.86+/-55.54 ng/mL, respectively). In Group 2, HDM-IgE levels reached a peak at week 3, remarkably higher (810.52+/-233.29 ng/mL) compared to those of Group 1 (169.86+/-55.54 ng/mL). The interleukin (IL)-4 and interferon (IFN)-beta in the HDM-stimulated culture supernatants of splenocytes were not significantly different among groups. We postulate that the cosensitization with BW may down-regulate the specific IgE response to HDM.

The temporal sequence of allergic sensitization and onset of infantile eczema

BACKGROUND

Eczema is commonly associated with sensitization in infants, but the causative role of sensitization in the development of eczema has been questioned.

OBJECTIVE

To determine if allergic sensitization increases the risk of developing eczema, or alternatively, if eczema increases the risk of developing allergic sensitization.

METHODS

We used data from the Melbourne Atopy Cohort Study, a prospective birth cohort of 552 infants with a family history of atopic disease. The main outcomes were risk of developing eczema from 6 months to 7 years of age in asymptomatic infants; and risk of developing sensitization, as measured by skin prick tests to milk, egg white, peanut, house dust mite, rye grass pollen and cat extracts, in previously unsensitized infants.

RESULTS

Sensitization to food extracts at 6 months was associated with an increased risk of developing eczema [hazard ratio (HR) 1.63, 95% confidence interval 1.13-2.35] up to 7 years of age, after excluding infants with eczema in the first 6 months. However, eczema in the first 6 months was also associated with increased risk of new sensitization at both 1 year (HR 2.34, 1.38-3.98) and 2 years (HR 3.47, 1.65-7.32).

CONCLUSION

In some infants, sensitization precedes and predicts the development of eczema, while in others eczema precedes and predicts the development of sensitization. This indicates that there are multiple pathways to atopic eczema.

N-3 polyunsaturated fatty acids and atopy in Korean preschoolers

Atopy is a growing problem for Korean children. Since eicosapentaenoic acid is a precursor of less active inflammatory eicosanoids, n-3 polyunsaturated fatty acids (PUFA) may have a protective effect on atopy. This study was undertaken to determine whether n-3 PUFA in red blood cells (RBC) is lower in atopic than in non-atopic preschoolers. Three hundred and eight Korean children aged 4-6 years were enrolled. Total RBC fatty acid composition was measured by gas chromatography. The prevalence of atopic dermatitis, allergic rhinitis, or asthma was 29%. Total RBC n-3 PUFA were lower in preschoolers with atopy than controls (9.8 +/- 1.2 vs. 11.4 +/- 1.6%; P<0.05), while n-6 PUFA (33.0 +/- 1.4 vs. 32.2 +/- 1.0%; P<0.05) and n-6/n-3 PUFA ratio (3.4 +/- 0.6 vs. 2.8 +/- 0.5; P<0.05) were greater. The following factors were also associated with an increase in atopy: higher saturated fatty acids (39.6 +/- 1.4 vs. 40.6 +/- 1.9; P<0.05) and arachidonic acid (15.3 +/- 1.6 vs. 16.0 +/- 2.9; P<0.05), and lower total PUFA (43.8 +/- 0.7 vs. 42.8 +/- 1.4; P<0.05) and omega-3 index (EPA + DHA; 9.1 +/- 0.8 vs. 7.8 +/- 0.5; P<0.05) in RBC. Maternal history of atopy was a significant (P<0.05) risk factor, while lactation was not. The results suggest that a reduced content of n-3 PUFA in the RBC membrane could play a role in early children atopy.

Perceived food allergy in children in 10 European nations. A randomised telephone survey

BACKGROUND

Food allergy is targeted as a public health priority by the European Union Commission. Parental perception of food allergy in their offspring is a proxy measure of the potential demand for allergy medicine services in the paediatric population.

METHODS

A representative sample of the general population was contacted by a randomised telephone survey in Austria, Belgium, Denmark, Finland, Germany, Greece, Italy, Poland, Slovenia and Switzerland. A standardised questionnaire was administered regarding parentally perceived food allergy reports, symptoms, foods and medical service use by their live-in children.

RESULTS

40,246 adults were polled, yielding data on 8,825 children. Parentally perceived food allergy prevalence was 4.7% (90% CI 4.2-5.2%). The most affected age group was 2- to 3-year olds (7.2%). Single-country incidence ranged between 1.7% (Austria) to 11.7% (Finland). Milk (38.5%), fruits (29.5%), eggs (19.0%) and vegetables (13.5%) were most often implicated, although with significant age-linked variations. Medical treatment was needed by 75.7% of affected children because of a food reaction. This translates into a proxy measure for food allergy prevalence of 3.75%. Skin symptoms were widespread (71.5%), followed by gastrointestinal (27.6%) and respiratory (18.5%) symptoms.

DISCUSSION

We provide the first point prevalence of parentally perceived food allergy in the general paediatric population across the European Union. Parental reports confirm the public health significance of adverse reactions to some foods in specified age groups. Our data may inform intervention planning, cost of illness assessments and quality-of-life-enhancing public health measures.

Evaluation of diet and growth in children with and without atopic eczema: follow-up study from birth to 4 years

Current research into dietary factors contributing to the development of allergic diseases is directed towards new active approaches instead of passive elimination diets. The present study aimed to investigate the explanatory role of the diet in a probiotic intervention study on the appearance of atopic eczema (AE) in childhood and the safety of perinatal supplementation with probiotics (Lactobacillus rhamnosus strain GG; ATCC 53 103). A prospective follow-up study from birth to 48 months of children (n 159) with a family history of allergic disease was carried out. Outcome measures included growth, dietary intake assessed with 4 d food diaries and their association with AE by logistic regression models. Increased intakes of retinol, Ca and Zn, with perinatal administration of probiotics, reduced the risk of AE, whilst an increase in intake of ascorbic acid increased the likelihood of AE. Perinatal administration of probiotics was safe, as it did not influence the height (mean difference 0·04 (95 % CI −0·33, 0·40) sd scores, P=0·852) or the weight-for-height (mean difference −3·35 (95 % CI −7·07, 0·37)%, P=0·077) of the children at 48 months with and without perinatal administration of probiotics. Up to 48 months, AE did not affect height (mean difference −0·05 (95 % CI −0·42, 0·33) sd scores, P=0·815), but mean weight-for-height in children with AE was −5·1 % (95 % CI −8·9, −1·2 %) lower compared with children without (P=0·010). The joint effects of nutrients and probiotics need to be considered in active prevention and management schemes for allergic diseases.

Prevalence and risk factors for allergic rhinitis in primary school children

OBJECTIVE

Allergic rhinitis is a common chronic illness of childhood. The aim of the study was to evaluate the prevalence and risk factors of allergic rhinitis in 6-12-year-old schoolchildren in Istanbul.

METHODS

A total of 2500 children aged between 6 and 12 years in randomly selected six primary schools of Istanbul were surveyed by using the International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire between April and May 2004.

RESULTS

Of them 2387 (1185 M/1202 F) questionnaires were appropriately completed by the parents with an overall response of 95.4%. The prevalence of physician-diagnosed allergic rhinitis was 7.9% (n=189). A family history of atopy (aOR=1.30, 95% CI=1.00-1.68), frequent respiratory tract infection (aOR=1.36, 95% CI=1.08-1.70) and sinusitis (aOR=2.29, 95% CI=1.64-3.19), antibiotic use in the first year of life (aOR=1.26, 95% CI=1.01-1.57), cat at home in the first year of life (aOR=2.21, 95% CI=1.36-3.61), dampness at home (aOR=1.31, 95% CI=1.04-1.65) and perianal redness (aOR=1.26, 95% CI=1.01-1.57) were significant for increased risk for allergic rhinitis. Frequent consumption of fruits and vegetables were inversely, and frequent consumption of lollipops and candies were positively associated with allergic rhinitis symptoms.

CONCLUSION

Our study reconfirmed that family history of atopy, frequent respiratory tract infections, antibiotics given in the first year of life, cat at home in the first year of life, dampness at home, perianal redness and dietary habits are important independent risk factors for AR. Researchers worldwide should be focused to these factors and try to develop policies for early intervention, primary and secondary preventions for allergic diseases.