Early predictors for developing allergic disease and asthma: examining separate steps in the 'allergic march'

Early inhalant allergen sensitization at component level: an analysis in atopic Dutch children

Background

Allergic rhinitis is a common respiratory disease in children and sensitization to inhalant allergens plays a significant role in its development. However, limited knowledge exists regarding sensitization profiles of inhalant allergen components in atopic children, particularly in the very young individuals. Understanding these profiles could provide insights into the early development of allergic rhinitis. The objective of this cross-sectional retrospective study was to evaluate the IgE-sensitization profiles to multiple inhalant allergen components and their clinical relevance in Dutch atopic children, with specific focus on children under the age of 4 years.

Methods

A total of 243 atopic children were included in the study and sensitization profiles were analyzed using multiplex microarray analysis (ISAC). Clinical information was obtained from records of a pediatric allergy outpatient clinic between 2011 and 2020. Specific IgE responses to inhalation allergen components from five allergen sources (grass pollen, tree pollen, house dust mite, cat and dog), were examined. The study encompassed children of different age groups and compared those with and without symptoms.

Results

The results demonstrated that sensitization to inhalant allergen components was present in 92% of the cohort. Sensitization was already evident at a young age (87%), including infancy, with a rapid increase in prevalence after 1 year of age. House dust mite emerged as the most predominant sensitizing allergen in early childhood, followed by tree pollen in later years. Sensitization patterns were similar between symptomatic and asymptomatic children, although symptomatic children exhibited higher frequencies and values. The sensitization profiles in very young children were comparable to those of children across all age groups.

Conclusion

These findings highlight the presence of sensitization to inhalant allergen components and the early onset of allergic rhinitis before the age of 4, including infancy, in Dutch atopic children. Notable allergen molecules in Dutch atopic children under the age of 4 years include Bet v 1, Fel d 1, Der f 1, Der p 1, Der p 10 and Phl p 4, with house dust mite sensitization being the most common among Dutch infants. Moreover, the prevalence of sensitization to inhalant allergens in this Dutch cohort surpassed that of general European populations, emphasizing the importance of early assessment and management of allergic rhinitis in young atopic children.

Impaired skin barrier and allergic sensitization in early infancy

BACKGROUND

Factors predicting allergic sensitization in the first 6 months of life are poorly understood. We aimed to determine whether eczema, dry skin, and high transepidermal water loss (TEWL) at 3 months were associated with allergic sensitization at 6 months of age and, secondarily, to establish whether these characteristics predicted sensitization from 3 to 6 months of age.

METHODS

At 3 months of age, 1,994 infants from the population-based PreventADALL birth cohort in Norway and Sweden were assessed for eczema and dry skin on the cheeks and/or extensors; impaired skin barrier function, defined as TEWL in the upper quartile (>9.4 g/m² /h), and allergen-specific IgE levels <0.1 kU_A /L, available in 830. At 6 months, we assessed allergic sensitization to any food (egg, cow's milk, peanut, wheat, soy) or inhalant (birch, timothy grass, dog, and cat) allergen by a skin prick test wheal diameter ≥2 mm larger than negative control.

RESULTS

Any sensitization was found in 198 of the 1,994 infants (9.9%), the majority to food allergens (n = 177, 8.9%). Eczema, dry skin, and high TEWL at 3 months increased the risk of sensitization at 6 months; adjusted odds ratios 4.20 (95% CI 2.93-6.04), 2.09 (95% CI 1.51-2.90) and 3.67 (95% CI 2.58-5.22), respectively. Eczema predicted sensitization with 55.6% sensitivity and 68.1% specificity; dry skin with 65.3% sensitivity and 57.3% specificity; and high TEWL with 61.7% sensitivity and 78.1% specificity.

CONCLUSION

Eczema, dry skin, and high TEWL at 3 months predicted allergic sensitization at 6 months of age.

Association between Health-Related Physical Fitness and Respiratory Diseases in Adolescents: An Age- and Gender-Matched Study

The current study examined the differences in health-related physical fitness (HRPF), physical activity (PA), and sedentary behavior (SB) between adolescents with and without ongoing respiratory diseases (RD). This study's participants were from 12 to 15 years old (7th-10th grade) in South Korea. Adolescents with RD were selected through RD-related questions (i.e., asthma, rhinitis, sinusitis, and bronchitis) (n = 139); in contrast, adolescents without RD, randomly selected from the general group, responded to any health problem-related questions as "No" (n = 139). HRPF was measured based on the FITNESSGRAM and EURO FIT test batteries and the measurements of HRPF included cardiovascular endurance, muscular strength, muscular endurance, flexibility, and body composition. All statistical analyses were conducted by SPSS 25.0, and the independent t-test was used to compare the HRPF and PA between the two groups. Moreover, the measured HRPF was compared with a series of analyses of three-way ANOVAs (age × gender × group). Adolescents with RD had a positive association with less participation in PA (p < 0.05; RD: 3081.81 ± 4793.37; general: 2073.64 ± 3123.47) and with more time spent on SB (above 12 h per week: RD group (38.85%) and general group (33.09%)). Furthermore, adolescents in the RD group showed significant effects on all components of HRPF (p < 0.05). Our study confirmed that HRPF is an essential predictor of adolescents' health outcomes, especially for those with RD. We suggest that increased HRPF can be an effective treatment for respiratory diseases in adolescents, and health practitioners should pay more attention to helping adolescents with RD to gain or maintain high HRPF.

Association between Physical Activity and Respiratory Diseases in Adolescents: An Age- and Gender-Matched Study

The purpose of the present cross-sectional study was to examine the impacts of allergic respiratory diseases on physical activity (PA), sedentary behaviors (SB), and body mass index (BMI) by matching age and gender with those adolescents without allergic respiratory diseases. This present study analyzed data from the 2019 Korea Youth Risk Behavior Web-based Survey (KYRBWS). Among 57,303 Korean adolescents who responded to the survey, the study divided adolescents into three different groups (i.e., general, asthma, and allergic rhinitis group). Asthma and allergic rhinitis groups included adolescents who checked on asthma- or allergic rhinitis-related questions as ‘yes’ (n = 259, n = 259), but the general group responded to any diseases-related question as ‘no’ (n = 259). The age and gender of participants among the three groups were matched. The results showed weight and BMI were significantly higher in asthma and allergic rhinitis groups compared to the general group (p < 0.001, p < 0.001). Furthermore, age, asthma, and allergic rhinitis were observed to be strong risk factors for predicting obesity in adolescents (BMI, >25.0 kg/m²). In addition, this study found allergic respiratory diseases strong impacts on BMI levels because adolescents with ongoing asthma, or allergic rhinitis symptoms were more likely to have the inevitability of further weight gain compared to the general adolescents. Therefore, not only national interest in adolescents with allergic respiratory disease is essential, but PA should be encouraged to prevent and alleviate these diseases due to obesity.

Machine Learning-Based DNA Methylation Score for Fetal Exposure to Maternal Smoking: Development and Validation in Samples Collected from Adolescents and Adults

BACKGROUND

Fetal exposure to maternal smoking during pregnancy is associated with the development of noncommunicable diseases in the offspring. Maternal smoking may induce such long-term effects through persistent changes in the DNA methylome, which therefore hold the potential to be used as a biomarker of this early life exposure. With declining costs for measuring DNA methylation, we aimed to develop a DNA methylation score that can be used on adolescent DNA methylation data and thereby generate a score for in utero cigarette smoke exposure.

METHODS

We used machine learning methods to create a score reflecting exposure to maternal smoking during pregnancy. This score is based on peripheral blood measurements of DNA methylation (Illumina's Infinium HumanMethylation450K BeadChip). The score was developed and tested in the Raine Study with data from 995 white 17-y-old participants using 10-fold cross-validation. The score was further tested and validated in independent data from the Northern Finland Birth Cohort 1986 (NFBC1986) (16-y-olds) and 1966 (NFBC1966) (31-y-olds). Further, three previously proposed DNA methylation scores were applied for comparison. The final score was developed with 204 CpGs using elastic net regression.

RESULTS

Sensitivity and specificity values for the best performing previously developed classifier ("Reese Score") were 88% and 72% for Raine, 87% and 61% for NFBC1986 and 72% and 70% for NFBC1966, respectively; corresponding figures using the elastic net regression approach were 91% and 76% (Raine), 87% and 75% (NFBC1986), and 72% and 78% for NFBC1966.

CONCLUSION

We have developed a DNA methylation score for exposure to maternal smoking during pregnancy, outperforming the three previously developed scores. One possible application of the current score could be for model adjustment purposes or to assess its association with distal health outcomes where part of the effect can be attributed to maternal smoking. Further, it may provide a biomarker for fetal exposure to maternal smoking. https://doi.org/10.1289/EHP6076.

Janus looks both ways: How do the upper and lower airways interact?

Our understanding of the relationship between the upper and lower airways has greatly increased as a consequence of epidemiologic and pharmacologic studies. A consistent body of scientific evidence supports the concept that rhinitis, rhinosinusitis and asthma may be the expression of a common inflammatory process, which manifests at different sites of the respiratory tract, at different times. This paradigm states that allergic reactions may begin at the local mucosa, but tend to propagate along the airway. Central to the allergic diathesis is the eosinophil and its interaction with the airway epithelium. The implications of the interplay between upper and lower airway are not only academic, but also important for diagnostic and therapeutic reasons. Furthermore, there is significant overlap in symptomatology and pathophysiology for childhood sleep disordered breathing (SDB) and asthma. Recent evidence supports an association between these two conditions, but causality has not been demonstrated. Regardless, it is important to recognize the overlap and evaluate for the other condition when one is present. In children with poorly controlled asthma, the presence of SDB may significantly contribute to asthma morbidity and, as such, should be actively excluded. On the other hand, clinical evaluation for asthma should be considered in children with SDB. Future robust longitudinal research is needed to explore the association between upper and lower airway diseases using objective measures in children.

The Influence of Age on the Relationship Between Allergic Rhinitis and Otitis Media

PURPOSE OF REVIEW

To examine the relationship between otitis media, allergic rhinitis, and age.

RECENT FINDINGS

Otitis media and allergic rhinitis are prevalent conditions with a controversial relationship. Some data suggest that these entities are significantly associated, either through allergic rhinitis inducing Eustachian tube dysfunction or through allergic pathophysiology simultaneously occurring intranasally and in the ear. Other studies, however, have refuted this relationship. For example, treatment with antihistamines does not reliably improve OME, making causation and association challenging to establish. Age may have an effect on the nature of the relationship between allergic rhinitis and otitis media, by impacting both the individual conditions and their association. Epidemiological, immunological, and adenoidal studies have suggested that differences occur with age, and this review encapsulates the related data and publications. We begin by evaluating how allergic rhinitis and otitis media each are affected by age, then evaluate the role that age may have in the relationship between the two conditions. Adult and pediatric literature are evaluated so as to include the full impact of age across patients' lifespan. Age induces changes in immunity, patterns of inflammation, and susceptibility to both allergic rhinitis and otitis media with effusion. Age may also be an effect modifier which impacts the nature of the relationship between these two conditions. The influence of age on the association between these highly prevalent conditions remains a topic of active study.

Associations Between Asthma and Sensitization to Pet or Pollen Allergens in Young Swedish Twins - The STOPPA Study

BACKGROUND

An association between childhood asthma and IgE sensitization has been established, but our understanding of the genetic and environmental contribution to it is incomplete. Our aim was to estimate the associations and dose-response relationship between asthma and sensitization to airborne allergens in Swedish 9- to 14-year-old twins. Additionally, we aimed to explore the importance of familial confounding from shared genes and environment using co-twin controls.

METHODS

In the STOPPA cohort, 752 same-sex twin children were screened with Phadiatop® (Thermo Fisher Scientific; Pharmacia, Uppsala, Sweden); if positive further analysis of IgE antibodies to airborne allergens of pets (cat, horse, dog), pollens (birch, timothy, mugwort), mites, and mold were performed. The associations between asthma and airborne allergens were assessed with generalized estimating equations. The co-twin control analysis was performed by conditional logistic regression.

RESULTS

Children with positive Phadiatop® had more than doubled odds of asthma (OR 2.53, 95% CI [1.74, 3.70]). Sensitization to pet allergens was associated with increased odds of asthma; for example, cat OR 4.15 (95% CI [2.67, 6.45]), with similar estimates for pollens; for example, birch OR 3.22 (95% CI [2.12, 4.91]). Associations persisted with sensitization as a categorical variable and for trend, indicating a dose-response relationship. Results remained in the co-twin analyses; for example, cat OR 4.75 (95% CI [1.62, 14.0]) and birch OR 5.00 (95% CI [1.45, 17.3]).

CONCLUSION

The association between childhood asthma and sensitization to airborne allergens remains in co-twin analyses, indicating they are not due to confounding from shared environmental or genetic factors.

Phenotypes of Atopic Dermatitis Depending on the Timing of Onset and Progression in Childhood

IMPORTANCE

Atopic dermatitis is an inflammatory, pruritic skin disease that often occurs in early infancy with a chronic course. However, a specific description of subtypes of atopic dermatitis depending on the timing of onset and progression of the disease in childhood is lacking.

OBJECTIVE

To identify different phenotypes of atopic dermatitis using a definition based on symptoms before age 6 years and to determine whether some subtypes are more at risk for developing other allergic diseases.

DESIGN, SETTING, AND PARTICIPANTS

The Protection Against Allergy Study in Rural Environments (PASTURE) is a European birth cohort where pregnant women were recruited between August 2002 and March 2005 and divided in 2 groups dependent on whether they lived on a farm. Children from this cohort with data on atopic dermatitis from birth to 6 years of age were included.

EXPOSURES

Atopic dermatitis, defined as an itchy rash on typical locations from birth to 6 years.

MAIN OUTCOMES AND MEASURES

The latent class analysis was used to identify subtypes of atopic dermatitis in childhood based on the course of symptoms. Multivariable logistic regressions were used to analyze the association between atopic dermatitis phenotypes and other allergic diseases.

RESULTS

We included 1038 children; of these, 506 were girls. The latent class analysis model with the best fit to PASTURE data separated 4 phenotypes of atopic dermatitis in childhood: 2 early phenotypes with onset before age 2 years (early transient [n = 96; 9.2%] and early persistent [n = 67; 6.5%]), the late phenotype with onset at age 2 years or older (n = 50; 4.8%), and the never/infrequent phenotype (n = 825; 79.5%), defined as children with no atopic dermatitis. Children with both parents with history of allergies were 5 times more at risk to develop atopic dermatitis with an early-persistent phenotype compared with children with parents with no history of allergies. Both early phenotypes were strongly associated with food allergy. The risk of developing asthma was significantly increased among the early-persistent phenotype (adjusted odds ratio, 2.87; 95% CI, 1.31-6.31). The late phenotype was only positively associated with allergic rhinitis.

CONCLUSIONS AND RELEVANCE

Using latent class analysis, 4 phenotypes of atopic dermatitis were identified depending on the onset and course of the disease. The prevalence of asthma and food allergy by 6 years of age was strongly increased among children with early phenotypes (within age 2 years), especially with persistent symptoms. These findings are important for the development of strategies in allergy prevention.

Life-course of atopy and allergy-related disease events in tropical sub-Saharan Africa: A birth cohort study

BACKGROUND

In high-income countries, allergy-related diseases (ARDs) follow a typical sequence, the 'Atopic March'. Little is known about the life-course of ARDs in the markedly different, low-income, tropical environment. We describe ARDs in a tropical, African birth cohort.

METHODS

Ugandan children were followed from birth to 9 years. ISAAC questionnaires were completed at intervals; doctor-diagnosed ARDs were recorded throughout follow-up. Skin prick tests (SPTs) were performed at 3 and 9 years. Atopy was defined as ≥1 positive SPT.

RESULTS

Of the 2345 live-born children, 1214 (52%) were seen at 9 years. Wheeze and eczema were common in infancy, but by 9 years, only 4% reported recent wheeze, 5% eczema and 5% rhinitis. Between 3 and 9 years, atopy prevalence increased from 19% to 25%. Atopy at 3 or 9 years was associated with reported ARD events at 9 years, for example OR = 5.2 (95% CI 2.9-10.7) for atopy and recent wheeze at 9 years. Reported or doctor-diagnosed ARD events in early childhood were associated with the same events in later childhood, for example OR = 4.4 (2.3-8.4) for the association between reported wheeze before 3 years with reported recent wheeze at 9 years, but progression from early eczema to later rhinitis or asthma was not observed.

CONCLUSION

Allergen sensitization started early in childhood and increased with age. Eczema and wheeze were common in infancy and declined with age. Atopy was strongly associated with ARD among the few affected children. The typical Atopic March did not occur. Environmental exposures during childhood may dissociate atopy and ARD.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION AND CLINICAL RELEVANCE

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

Allergic disease in 8-year-old children is preceded by delayed B cell maturation

BACKGROUND

We previously reported that exposure to a farming environment is allergy-protective, while high proportions of neonatal immature/naïve CD5⁺ B cells and putative regulatory T cells (Tregs) are risk factors for development of allergic disease and sensitization up to 3 years of age.

OBJECTIVE

To examine if B and T cell maturation are associated with allergic disease and farming environment over the first 8 years in life.

METHODS

In the prospective FARMFLORA study, including both farming and non-farming families, 48 of 65 children took part in the 8-year follow-up study. Various B and T cell maturation variables were examined in blood samples obtained at several occasions from birth to 8 years of age and related to doctors' diagnosed allergic disease and sensitization, and to farming environment.

RESULTS

We found that the incidence of allergic disease was lower among farmers' compared to non-farmers' children during the 8-year follow-up period, and that farmers' children had higher proportions of memory B cells at 8 years of age. Moreover, a high proportion of neonatal CD5⁺ B cells was a risk factor for and may predict development of allergic disease at 8 years of age. A high proportion of Tregs was not protective against development of these conditions.

CONCLUSION AND CLINICAL RELEVANCE

High proportions of neonatal naïve B cells remained as a risk factor for allergic disease in school-aged children. Thus, the accelerated B cell maturation observed among farmers' children may be crucial for the allergy-protective effect of a farming environment.

The allergic march comprises the coexistence of related patterns of allergic disease not just the progressive development of one disease

Aim

This study explored the development and comorbidity of allergic diseases by analysing the relationship between allergic manifestations in infancy and at the age of 8.

Methods

We included 5654 children born in Sweden in 2003 in a longitudinal study. Parents answered postal questionnaires when the children were six months and one, four‐and‐a‐half and eight years of age.

Results

The response rate at eight years was 4051 (71.6%), and we analysed 3382 children with complete data. The number of manifestations in infancy increased the risk of allergic disease at eight years of age: 72% of children with one early manifestation were symptom free at 8, compared to 45% with two or more manifestations. Similar manifestations occurred in infancy and at the age of 8, for example recurrent wheeze increased the risk of doctor‐diagnosed asthma by an adjusted odds ratio of 6.5. Eczema and food allergy independently increased the risk of all four allergic manifestations at eight years.

Conclusion

Allergic disease at the age of 8 was related to the number of allergic manifestations in infancy. Manifestations were similar at both ages, suggesting an allergic march with the coexistence of disease patterns rather than the progressive development of one disease.

Evidence in immunotherapy for paediatric respiratory allergy: Advances and recommendations

Allergic respiratory diseases are major health problems in paediatric population due their high level of prevalence and chronicity, and to their relevance in the costs and quality of life. One of the most important risk factors for the development of airway diseases in children and adolescents is atopy. The mainstays for the treatment of these diseases are avoiding allergens, controlling symptoms, and preventing them through sustained desensitization by allergen immunotherapy (AIT). AIT is a treatment option that consists in the administration of increasing amounts of allergens to modify the biological response to them, inducing long-term tolerance even after treatment has ended. This treatment approach has shown to decrease symptoms and improve quality of life, becoming cost effective for a large number of patients. In addition, it is considered the only treatment that can influence the natural course of the disease by targeting the cause of the allergic inflammatory response. The aim of this publication is to reflect the advances of AIT in the diagnosis and treatment of allergic respiratory diseases in children and adolescents reviewing articles published since 2000, establishing evidence categories to support the strength of the recommendations based on evidence. The first part of the article covers the prerequisite issues to understand how AIT is effective, such as the correct etiologic and clinical diagnosis of allergic respiratory diseases. Following this, the article outlines the advancements in understanding the mechanisms by which AIT achieve immune tolerance to allergens. Administration routes, treatment regimens, dose and duration, efficacy, safety, and factors associated with adherence are also reviewed. Finally, the article reviews future advances in the research of AIT.

Predictors of allergen sensitization in Singapore children from birth to 3 years

Background

Immune responses in allergic diseases begin with allergen sensitization, which usually occurs in childhood. Allergen sensitization involves a complex interplay of genetic and environmental factors, and sensitization patterns may change with age.

Objective

To determine the predictors of allergen sensitization in the first 3 years of life in the growing up in Singapore towards healthy outcomes (GUSTO) prospective birth cohort study.

Methods

Interviewers collected information on demographics, family history of allergy, social and lifestyle factors, and the child’s health. We analyzed data from 849 children who completed skin prick testing (SPT) to inhalant allergens (house dust mites: Dermatophagoides pteronyssinus, Dermatophagoides farinae, and Blomia tropicalis) and food allergens (egg, peanut and cow’s milk) to assess risk factors for allergen sensitization at 18 months. To ensure that clinical phenotypes preceded allergen sensitization, we also analyzed data from 649 children who had a negative skin prick test at 18 months and completed skin prick testing at 36 months.

Results

We observed a significant association between eczema reported before 18 months and a positive SPT at 18 months [aOR 4.5 (1.9–10.7)]. Ninety-five (14.6 %) children with negative SPTs at 18 months developed positive tests at 36 months. Onset of eczema before 18 months was associated with an increased risk of new allergen sensitization at 36 months among children non-sensitized at 18 months [aOR 3.4 (1.2–9.3)]. An association was seen between wheeze reported before 18 months and new allergen sensitization at 36 months [aOR 3.2 (1.1–9.1)]. We found no significant association, however, between rhinitis reported before 18 months and new allergen sensitization at 36 months.

Conclusions

Early onset of eczema and wheeze are risk factors for later allergen sensitization, suggesting a possible increased susceptibility to allergen exposure through an impaired skin barrier or defective airway epithelium.

Trial registration NCT01174875 Registered 1 July 2010, retrospectively registered

Risk factors for recurrent wheezing in infants: a case-control study

OBJECTIVE

To evaluate the association between recurrent wheezing and atopy, the Asthma Predictive Index, exposure to risk factors, and total serum IgE levels as potential factors to predict recurrent wheezing.

METHODS

A case-control study with infants aged 6-24 months treated at a specialized outpatient clinic from November 2011 to March 2013. Evaluations included sensitivity to inhalant and food antigens, positive Asthma Predictive Index, and other risk factors for recurrent wheezing (smoking during pregnancy, presence of indoor smoke, viral infections, and total serum IgE levels).

RESULTS

We evaluated 113 children: 65 infants with recurrent wheezing (63.0% male) with a mean age of 14.8 (SD = 5.2) months and 48 healthy infants (44.0% male) with a mean age of 15.2 (SD = 5.1) months. In the multiple analysis model, antigen sensitivity (OR = 12.45; 95%CI 1.28–19.11), positive Asthma Predictive Index (OR = 5.57; 95%CI 2.23–7.96), and exposure to environmental smoke (OR = 2.63; 95%CI 1.09–6.30) remained as risk factors for wheezing. Eosinophilia ≥ 4.0% e total IgE ≥ 100 UI/mL were more prevalent in the wheezing group, but failed to remain in the model. Smoking during pregnancy was identified in a small number of mothers, and secondhand smoke at home was higher in the control group.

CONCLUSIONS

Presence of atopy, positive Asthma Predictive Index and exposure to environmental smoke are associated to recurrent wheezing. Identifying these factors enables the adoption of preventive measures, especially for children susceptible to persistent wheezing and future asthma onset.

Monitoring asthma in childhood

The goal of asthma treatment is to obtain clinical control and reduce future risks to the patient. However, to date there is limited evidence on how to monitor patients with asthma. Childhood asthma introduces specific challenges in terms of deciding what, when, how often, by whom and in whom different assessments of asthma should be performed. The age of the child, the fluctuating course of asthma severity, variability in clinical presentation, exacerbations, comorbidities, socioeconomic and psychosocial factors, and environmental exposures may all influence disease activity and, hence, monitoring strategies. These factors will be addressed in herein.

We identified large knowledge gaps in the effects of different monitoring strategies in children with asthma. Studies into monitoring strategies are urgently needed, preferably in collaborative paediatric studies across countries and healthcare systems.

Monitoring asthma in children is essential for disease control and should reflect age, triggers and disease activityhttp://ow.ly/J0k7f

Five-year risk of incident disease following a diagnosis of chronic rhinosinusitis

BACKGROUND

Chronic rhinosinusitis (CRS) has a broad range of comorbidities. Due to a lack of longitudinal studies, it is not known whether these comorbidities cause CRS, are promoted by CRS, or share a systemic disease process with CRS.

OBJECTIVE

The objective of this study was to determine the risk of incident disease within 5 years after a new diagnosis of CRS with nasal polyps (CRSwNP) and without nasal polyps (CRSsNP).

METHODS

We conducted a case-control study nested within the longitudinal cohort of primary care patients in the Geisinger Clinic using electronic health record data. We evaluated incident disease over 5 years in newly diagnosed CRSwNP and CRSsNP cases compared to controls using multivariable Cox regression models.

RESULTS

CRSsNP (n = 3612) cases were at greater risk (HR, 95% confidence interval) than controls for incidence of: upper airway diseases, including adenotonsillitis (3.29, 2.41-4.50); lower aerodigestive tract diseases, including asthma (2.69, 2.14-3.38); epithelial conditions, including atopic dermatitis (2.75, 1.23-6.16); and hypertension (1.38, 1.19-1.61). CRSwNP (n = 241) cases were at greater risk for obesity than controls (1.74, 1.08-2.80), but CRSwNP was not associated with other diseases.

CONCLUSION

The risk of other diseases associated with CRS adds to the burden of an already highly burdensome condition, and suggests either that CRS promotes onset of other diseases or is an indicator of systemic disease processes. Different patterns of association with diseases by CRS phenotype may be due to CRSwNP sample size limitations or reflect a different pattern of disease onset by phenotype. These findings have implications for screening guidelines and care of CRS patients.

Meta-analysis identifies seven susceptibility loci involved in the atopic march

Eczema often precedes the development of asthma in a disease course called the ‘atopic march'. To unravel the genes underlying this characteristic pattern of allergic disease, we conduct a multi-stage genome-wide association study on infantile eczema followed by childhood asthma in 12 populations including 2,428 cases and 17,034 controls. Here we report two novel loci specific for the combined eczema plus asthma phenotype, which are associated with allergic disease for the first time; rs9357733 located in EFHC1 on chromosome 6p12.3 (OR 1.27; P=2.1 × 10⁻⁸) and rs993226 between TMTC2 and SLC6A15 on chromosome 12q21.3 (OR 1.58; P=5.3 × 10⁻⁹). Additional susceptibility loci identified at genome-wide significance are FLG (1q21.3), IL4/KIF3A (5q31.1), AP5B1/OVOL1 (11q13.1), C11orf30/LRRC32 (11q13.5) and IKZF3 (17q21). We show that predominantly eczema loci increase the risk for the atopic march. Our findings suggest that eczema may play an important role in the development of asthma after eczema.

The development of asthma following eczema is known as the atopic march. Here the authors conduct a GWAS on affected children and identify two novel loci associated with the disease phenotype.

Change in the manifestations of asthma and asthma-related traits in childhood: a latent transition analysis

It is known that asthma is a heterogeneous entity whose manifestations vary with age. Our objective was to examine changes in the manifestation of asthma and asthma-related traits in childhood by defining empirically derived childhood asthma phenotypes and examining their transitions over time.To define the phenotypes we used data on respiratory symptoms, healthcare utilisation, medications, spirometry, airway hyperresponsiveness (AHR), exhaled nitric oxide concentration and atopy from a birth cohort recruited on the basis of having a first-degree relative with asthma. Data were acquired at ages 1.5-11.5 years and analysed using latent transition analysis.In a study population of 370 participants, we classified subjects into four phenotypes: 1) nonatopic, few symptoms (prevalence range from 1.5 to 5 years: 52-60%), 2) atopic, few symptoms (3-21%), 3) nonatopic, asthma and rhinitis symptoms (13-35%), and 4) atopic, asthma and rhinitis symptoms (2-14%) in early childhood; and 1) nonatopic, no respiratory disease (prevalence range from 8 to 11.5 years: 41-46%), 2) atopic, no respiratory disease (23-33%), 3) nonatopic, asthma symptoms, no AHR or airway inflammation (8-12%) and 4) atopic asthma (19%) in mid-childhood. Transitioning between phenotypes was common in early childhood, but less common in later childhood.This analysis represents the first attempt to incorporate longitudinal patterns of several manifestations of asthma into a single model to simultaneously define phenotypes and examine their transitions over time. It provides quantitative support for the view that asthma is a heterogeneous entity, and that some children with wheeze and other respiratory symptoms in early life progress to asthma in mid-childhood, while others become asymptomatic.

Allergic sensitization and filaggrin variants predispose to the comorbidity of eczema, asthma, and rhinitis: results from the Isle of Wight birth cohort

BACKGROUND

Allergic sensitization and filaggrin gene (FLG) variants are important risk factors for allergic disorders; however, knowledge on their individual and interactive effects on the coexistence of eczema, asthma, and rhinitis is lacking.

OBJECTIVE

This study aimed at investigating the single and combined effects of allergic sensitization and FLG variants on the development of single and multiple allergic disorders.

METHODS

The Isle of Wight birth cohort (n = 1456) has been examined at 1, 2, 4, 10, and 18 years of age. Repeated measurements of eczema, asthma, rhinitis, and skin prick tests were available for all follow-ups. FLG variants were genotyped in 1150 participants. Associations of allergic sensitization and FLG variants with single and multiple allergic disorders were tested in log-binomial regression analysis.

RESULTS

The prevalence of eczema-, asthma-, and rhinitis-only ranged from 5.6% to 8.5%, 4.9% to 10.2%, and 2.5% to 20.4%, respectively, during the first 18 years of life. The coexistence of allergic disorders is common, with approximately 2% of the population reporting the comorbidity of 'eczema, asthma, and rhinitis' during the study period. In repeated measurement analyses, allergic sensitization and FLG variants, when analysed separately, were associated with having single and multiple allergic disorders. Of particular significance, their combined effect increased the risk of 'eczema and asthma' (RR = 13.67, 95% CI: 7.35-25.42), 'asthma and rhinitis' (RR = 7.46, 95% CI: 5.07-10.98), and 'eczema, asthma, and rhinitis' (RR = 23.44, 95% CI: 12.27-44.78).

CONCLUSIONS AND CLINICAL RELEVANCE

The coexistence of allergic disorders is frequent, and allergic sensitization and FLG variants jointly increased risk of allergic comorbidities, which may represent more severe and complex clinical phenotypes. The interactive effect and the elevated proportion of allergic comorbidities associated with allergic sensitization and FLG variants emphasize their joint importance in the pathogenesis of allergic disorders.

High proportions of FOXP3(+) CD25(high) T cells in neonates are positively associated with allergic sensitization later in childhood

Background

The role of FOXP3⁺ regulatory T cells in the prevention against sensitization and allergy development is controversial.

Objective

We followed 65 newborn Swedish children from farming and non-farming families from birth to 3 years of age and investigated the relation between CD4⁺ T cell subsets in blood samples and development of sensitization and allergic disease.

Methods

The proportions of FOXP3⁺CD25^high, CTLA-4⁺CD25⁺, CD45RO⁺, HLA-DR⁺, CCR4⁺ or α4β7⁺ within the CD4⁺ T cell population were examined by flow cytometry of blood samples at several time-points. Mononuclear cells were isolated from blood and stimulated with birch allergen, ovalbumin or the mitogen PHA, and the levels of IL-1β, IL-6, TNF, IFN-γ, IL-5 and IL-13 were measured. A clinical evaluation regarding the presence of allergen-specific IgE and allergy was performed at 18 and 36 months of age.

Results

Multivariate discriminant analysis revealed that children who were sensitized at 18 or 36 months of age had higher proportions of FOXP3⁺CD25^high T cells at birth and at 3 days of life than children who remained non-sensitized, whereas allergy was unrelated to the neonatal proportions of these cells. The proportions of CTLA-4⁺CD25⁺ T cells were unrelated to both sensitization and allergy. The association between higher proportions of FOXP3⁺CD25^high T cells and sensitization persisted after exclusion of farmer's children. Finally, a farming environment was associated with lower proportions of FOXP3⁺CD25^high T cells in early infancy and to a more prominent T cell memory conversion and cytokine production.

Conclusion & Clinical Relevance

Our results indicate that high proportions of FOXP3⁺CD25^high T cells in neonates are not protective against later sensitization or development of allergy.

Reprint of: Perinatal and early childhood environmental factors influencing allergic asthma immunopathogenesis

BACKGROUND

The prevalence of asthma has increased dramatically over the past several decades. While hereditary factors are highly important, the rapid rise outstrips the pace of genomic variation. Great emphasis has been placed on potential modifiable early life exposures leading to childhood asthma.

METHODS

We reviewed the recent medical literature for important studies discussing the role of the perinatal and early childhood exposures and the inception of childhood asthma.

RESULTS AND DISCUSSION

Early life exposure to allergens (house dust mite (HDM), furred pets, cockroach, rodent and mold), air pollution (nitrogen dioxide (NO2), ozone (O3), volatile organic compounds (VOCs), and particulate matter (PM)) and viral respiratory tract infections (Respiratory syncytial virus (RSV) and human rhinovirus (hRV)) has been implicated in the development of asthma in high risk children. Conversely, exposure to microbial diversity in the perinatal period may diminish the development of atopy and asthma symptoms.

Perinatal and early childhood environmental factors influencing allergic asthma immunopathogenesis

BACKGROUND

The prevalence of asthma has increased dramatically over the past several decades. While hereditary factors are highly important, the rapid rise outstrips the pace of genomic variation. Great emphasis has been placed on potential modifiable early life exposures leading to childhood asthma.

METHODS

We reviewed the recent medical literature for important studies discussing the role of the perinatal and early childhood exposures and the inception of childhood asthma.

RESULTS AND DISCUSSION

Early life exposure to allergens (house dust mite (HDM), furred pets, cockroach, rodent and mold), air pollution (nitrogen dioxide (NO(2)), ozone (O(3)), volatile organic compounds (VOCs), and particulate matter (PM)) and viral respiratory tract infections (Respiratory syncytial virus (RSV) and human rhinovirus (hRV)) has been implicated in the development of asthma in high risk children. Conversely, exposure to microbial diversity in the perinatal period may diminish the development of atopy and asthma symptoms.

High proportion of CD5+ B cells in infants predicts development of allergic disease

Delayed maturation of the immune system has been proposed to be a risk factor for development of allergy, but B cell maturation in relation to allergic disease has not been examined. B cells lose CD5 and acquire CD27 during maturation from immature via mature/naive to Ig-secreting cells and memory cells. We sought to investigate B cell maturation in relation to development of allergic disease and sensitization in the FARMFLORA birth cohort including 65 Swedish children. Total B cell numbers, proportions of CD5(+) and CD27(+) B cells, and levels of IgM, IgG, IgA, and IgE were measured in blood on repeated occasions from birth to 36 mo of age, and related to allergic disease and sensitization at 18 and 36 mo of age with multivariate discriminant analysis. We also compared the expression of CD24 and CD38 within CD5(+) and CD5(neg) B cells in children and in adults. We found that infants with a high proportion of CD5(+) B cells at birth and at 1 mo of age had an increased risk for having allergic disease at 18 and 36 mo of life. Further, the proportions of CD5(+) B cells at 1 mo of age were inversely correlated with total IgG levels at 18 and 36 mo of age. The majority of the CD5(+) B cells were of a CD24(hi/+)CD38(hi/+) immature/naive phenotype at birth (97%), 7 y of age (95%), and in adults (86%). These results suggest that development of allergic disease is preceded by an immaturity in neonatal B cell phenotype.

Allergy history as a predictor of early onset adenoids/adenotonsillar hypertrophy among Nigerian children

BACKGROUND

Previous reports have established the association of allergy with adenoidal and tonsillar hypertrophy, and adenotonsillar hypertrophy is a well known co-morbid factor in patients with allergic rhinitis. Very little is known about the association of history of allergy with timing of first presentation in adenotonsillitis patients.

SETTING

Tertiary care urban referral hospital.

STUDY DESIGN

Descriptive analysis of prospectively collected data.

METHODS

All cases which had adenotonsillectomy carried out between September 2005 and September 2012 at National Hospital Abuja that met the selection criteria were recruited and analyzed on the basis of family history of allergy in first degree relatives, clinical history of allergic rhinitis, asthma and atopic dermatitis.

RESULT

Total of 434 cases were recruited. Mean age was 5 years (range 9 months-15 years, std. dev. 3.535). 56% of participants were aged 3 years and below. 22, 15, and 16% of participants aged 3 years and below had family history of allergy, allergic rhinitis and atopic dermatitis respectively compared to 6, 4 and 4% for participants aged above 3 years. The mean age at onset of symptoms is 7.59, 10.32, and 13.62 months for participants with family history of allergy, clinical allergic rhinitis and atopic dermatitis respectively and 23.890 months for participants with no history of atopy or allergy. Family history of allergy significantly predicts onset of symptoms before age 6 months (OR 7.59, 95% CI 4.74-12.12, P<0.0001).

CONCLUSIONS

Family history of allergy and presence of clinical allergic or atopic dermatitis are related to early onset of symptoms in Nigerian children with adenoids/adenotonsillar hypertrophy.

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.

Pets at birth do not increase allergic disease in at-risk children

BACKGROUND

The literature is contradictory concerning pet exposure and risk of allergic disease in childhood especially among those with a family history of allergy.

OBJECTIVE

To investigate the relationship between cat and dog exposure at birth and allergic outcomes over the first 12 years in a birth cohort selected for familial allergy.

METHODS

A prospective birth cohort of 620 infants with a family history of allergic diseases was recruited. Data on pet keeping, family demographics and cord blood samples were collected at birth. Information on childhood wheeze, eczema and hay fever was collected 18 times in the first 2 years, at 7 years and at 12 years. Skin prick tests were conducted at 2, 7 and 12 years, and in parents. Regression analyses were used to investigate the relevant associations while adjusting for potential confounders.

RESULTS

Exposure to cats or dogs at birth showed a moderate reduction in risk of wheeze (aOR = 0.76; 95% CI 0.53, 1.09) and hay fever (aOR = 0.71; 0.49, 1.02) after 7 years of age. Protective effects were stronger in children of non-sensitized fathers (aOR wheeze 0.55; 0.31, 0.98; aOR hay fever 0.33; 0.15, 0.77 on exposure to cats alone, or cats or dogs at birth). Pet keeping was not related to cord blood IgE or sensitization from 2 to 12 years.

CONCLUSIONS AND CLINICAL RELEVANCE

Pets at birth either decreased or had no effect on allergic disease up to age 12. We found no evidence that exposure to cats or dogs at birth increases the risk of allergic disease in high-risk children.

Dichlorophenol-containing pesticides and allergies: results from the US National Health and Nutrition Examination Survey 2005-2006

BACKGROUND

Epidemiologic studies support the hypothesis that reduced microbial exposure in westernized societies promotes atopy. Dichlorophenols are widely used as pesticides and for chlorination of water. They have a strong bactericidal effect that could affect microflora in the environment. However, it is unknown whether their use is associated with a higher prevalence of allergies.

OBJECTIVE

To test the association between exposure to environmental pesticides represented by dichlorophenols and allergic sensitization measured by allergen-specific serum IgE levels in a US nationally representative sample of 2,211 persons 6 years and older in the National Health and Nutrition Examination Survey 2005-2006.

METHODS

Exposure to dichlorophenols was defined as high if their levels in urine were present at the 75th percentile and above. Association of the high exposure to dichlorophenols with sensitization to food and environmental allergens was assessed in logistic regression models after adjustment for sample weights and potential confounders.

RESULTS

Sensitizations to 1 or more food allergens were more common in those with exposure to 2 dichlorophenol metabolites. After multivariable adjustment, urine dichlorophenol levels at the 75th percentile and above were associated with the presence of sensitization to foods (odds ratio, 1.8; 95% confidence interval, 1.2-2.5; P = .003). No significant association was found between dichlorophenol exposure and sensitization to aeroallergens alone.

CONCLUSION

High urine levels of dichlorophenols are associated with the presence of sensitization to foods in a US population. Excessive use of dichlorophenols may contribute to the increasing incidence of food allergies in westernized societies.

Lung dendritic cell developmental programming, environmental stimuli, and asthma in early periods of life

Dendritic cells (DCs) are important cells of our innate immune system. Their role is critical in inducing adaptive immunity, tolerance, or allergic response in peripheral organs—lung and skin. The lung DCs are not developed prenatally before birth. The DCs develop after birth presumably during the first year of life; exposures to any foreign antigen or infectious organisms during this period can significantly affect DC developmental programming and generation of distinct DC phenotypes and functions. These changes can have both short-term and long-term health effects which may be very relevant in childhood asthma and predisposition for a persistent response in adulthood. An understanding of DC development at molecular and cellular levels can help in protecting neonates and infants against problematic environmental exposures and developmental immunotoxicity. This knowledge can eventually help in designing novel pharmacological modulators to skew the DC characteristics and immune responses to benefit the host across a lifetime.

Early eczema and the risk of childhood asthma: a prospective, population-based study

Background

Severe eczema in young children is associated with an increased risk of developing asthma and rhino-conjunctivitis. In the general population, however, most cases of eczema are mild to moderate. In an unselected cohort, we studied the risk of current asthma and the co-existence of allergy-related diseases at 6 years of age among children with and without eczema at 2 years of age.

Methods

Questionnaires assessing various environmental exposures and health variables were administered at 2 years of age. An identical health questionnaire was completed at 6 years of age. The clinical investigation of a random subsample ascertained eczema diagnoses, and missing data were handled by multiple imputation analyses.

Results

The estimate for the association between eczema at 2 years and current asthma at 6 years was OR=1.80 (95% CI 1.10-2.96). Four of ten children with eczema at 6 years had the onset of eczema after the age of 2 years, but the co-existence of different allergy-related diseases at 6 years was higher among those with the onset of eczema before 2 years of age.

Conclusions

Although most cases of eczema in the general population were mild to moderate, early eczema was associated with an increased risk of developing childhood asthma. These findings support the hypothesis of an atopic march in the general population.

Trial registration

The Prevention of Allergy among Children in Trondheim study has been identified as ISRCTN28090297 in the international Current Controlled Trials database

Does eczema in infancy cause hay fever, asthma, or both in childhood? Insights from a novel regression model of sibling data

BACKGROUND

The atopic march hypothesis proposes that eczema precedes the development of asthma and allergic rhinitis.

OBJECTIVE

We sought to assess the evidence for a causal effect of infantile eczema on childhood hay fever, asthma, or both.

METHODS

We used parental reports on infantile eczema and childhood asthma and hay fever for 3778 pairs of 7-year-olds matched to their sibling closest in age within 2 years from the Tasmanian Longitudinal Health Study. We analyzed paired sibling data using a logistic regression model that allowed inference about a causal effect of a familial predictor on a child's outcome by examining the change in association with their cosibling's predictor after adjusting for their own predictor status.

RESULTS

Siblings were concordant for infantile eczema (tetrachoric correlation, 0.40). For having both hay fever and asthma by age 7 years, the association with cosibling's eczema was an odds ratio (OR) of 1.98 (95% CI, 1.37-2.86), which reduced after adjusting for own eczema to an OR of 1.65 (95% CI, 1.17-2.34). For having hay fever only, the association with cosibling's eczema was an OR of 1.68 (95% CI, 1.22-2.31) before and an OR of 1.59 (95% CI, 1.19-2.14) after adjusting for own eczema. There was no association between having asthma only and cosibling's eczema (OR, 1.00; 95% CI, 0.77-1.30).

CONCLUSIONS

Eczema in infancy might have a causal effect on hay fever in children with and perhaps without asthma. The association of infantile eczema on asthma in children without hay fever, which might be early transient wheeze, is unlikely to be causal or familial. These findings have implications for hay fever prevention.

Health impacts of air pollution: a life course approach for examining predictors of respiratory health in adulthood

PURPOSE

This research applies a life course health development framework to examine the impacts of childhood exposure to air pollution on respiratory health in adulthood.

METHODS

This prospective cohort study uses data collected from children originally studied in the 1970/1980s, including exposure to air pollution, indoor exposures, sociodemographic variables, and health outcomes data. Thirty years later, a self-administered questionnaire was used to collect data from adulthood on health status, occupational and residential histories, socioeconomic status, and lifestyle.

RESULTS

Overall, 29% of respondents were diagnosed with at least one respiratory condition and 24% have persistent respiratory symptoms in adulthood. Significant neighborhood differences in exposure variables and adulthood health outcomes were found. Predictors of adulthood respiratory health include asthma diagnosis or chest illness in childhood, parental record of respiratory symptoms, other medical diagnosis in adulthood, fair/poor self-perceived health, smoking/exposure to smoking, and residing in a property built before 1950. Results suggest that exposure to ambient total suspended particulates in childhood is preventative for diagnosis with at least one respiratory condition in adulthood.

CONCLUSION

Findings suggest that long-term childhood exposure to air pollution does not predict respiratory conditions and symptoms in adulthood. However, respiratory health in childhood predicts adulthood respiratory health, thus suggesting that the health impacts of any exposures that impact respiratory health during critical or sensitive times in childhood are long term.

Dissecting the causes of atopic dermatitis in children: less foods, more mites

Atopic dermatitis (AD) is a common, chronic or chronically relapsing, multifactorial skin disease that mainly occurs in children but affects also adults. AD usually begins early in life and often concerns people with a personal or family history of asthma and allergic rhinitis. AD is characterized by eczematous changes in the epidermis and originates from a late, T-cell mediated reaction associated to the formation and production of memory T-cell of TH2 type, occurrence of homing receptor at skin level and cutaneous lymphocyte-associated (CLA) antigens. Extrinsic or allergic AD, but not intrinsic AD, shows high total serum IgE levels and the presence of specific IgE for environmental and food allergens. A pivotal role in the pathogenesis of AD is played by filaggrin, a protein contained in the granular layer of the epidermis regulating the aggregation of keratin filaments. Mutation in the filaggrin gene causes decreased barrier function of the corny layers of the epidermis. This favours the enter through the skin of environmental allergens, especially the house dust mite, that further facilitates such entering by the proteolytic activity of its major allergen Der p 1. In fact, recent advances suggest that the dust mite, more than foods, is the major cause of allergic AD. As far as the causal diagnosis of AD is concerned, there is notable evidence supporting the capacity of the atopy patch test (APT) to reproduce the pathophysiologic events of AD. This makes APT a valuable diagnostic tool for AD.

Interplay of filaggrin loss-of-function variants, allergic sensitization, and eczema in a longitudinal study covering infancy to 18 years of age

Background

Immune specific genes as well as genes regulating the formation of skin barrier are major determinants for eczema manifestation. There is a debate as to whether allergic sensitization and filaggrin gene (FLG) variants lead to eczema or FLG variants and eczema increase the risk of allergic sensitization. To investigate the time-order between eczema and allergic sensitization with respect to FLG variants, data from a large prospective study covering infancy to late adolescence were analyzed.

Methodology/Principal Findings

Repeated measurements of eczema and allergic sensitization (documented by skin prick tests) at ages 1, 2, 4, 10, and 18 years were ascertained in the Isle of Wight birth cohort (n = 1,456). Three transition periods were analyzed: age 1-or-2 to 4, 4 to 10, and 10 to 18 years. FLG variants were genotyped in 1,150 participants. Over the three transition periods, in temporal sequence analyses of initially eczema-free participants, the combined effect of FLG variants and allergic sensitization showed a 2.92-fold (95% CI: 1.47–5.77) increased risk ratio (RR) of eczema in subsequent examinations. This overall risk was more pronounced at a younger age (transition period 1-or-2 to 4, RR = 6.47, 95% CI: 1.96–21.33). In contrast, FLG variants in combination with eczema showed a weaker, but significant, risk ratio for subsequent allergic sensitization only up to 10 years of age.

Conclusions/Significance

Taking the time order into account, this prospective study demonstrates for the first time, that a combination of FLG variants and allergic sensitization increased the risk of eczema in subsequent years. Also FLG variants interacted with eczema and increased the risk of subsequent allergic sensitization, which, was limited to the younger age. Hence, early restoration of defective skin barrier could prevent allergic sensitization and subsequently reduce the risk of eczema development.

Rhinitis in children less than 6 years of age: current knowledge and challenges

Rhinitis is a disease of the upper airway characterized by runny and/or blocked nose and/or sneezing. Though not viewed as a life threatening condition, it is also recognized to impose significant burden to the quality of life of sufferers and their caretakers and imposes an economic cost to society. Through a PubMed online search of the literature from 2006 to September 2011, this paper aims to review the published literature on rhinitis in young children below the age of 6 years. It is apparent from epidemiology studies that rhinitis in this age group is a relatively common problem. The condition has a heterogenous etiology with classification into allergic and non-allergic rhinitis. Respiratory viral infections may play a role in the pathogenesis of long standing rhinitis, but definitive studies are still lacking. Treatment guidelines for management are lacking for this age group, and is a significant unmet need. Although the consensus is that co-morbidities including otitis media with effusion, adenoidal hypertrophy and asthma, are important considerations of management of these children. Pharmacotherapy is limited for young children especially for those below the age of 2 years. This review underscores the lack of understanding of rhinitis in early childhood and therefore the need for further research in this area.

Childhood asthma and indoor allergen exposure and sensitization in Buffalo, New York

This nested case-control study examined the association between prevalent asthma and indoor allergen sensitization and/or exposure among children (aged 5-17 years) in Buffalo, New York. The study included a self-administered questionnaire, clinical interviews, skin allergen sensitivity tests and home dust sampling for house dust mites, cat, dog, cockroach and mouse allergens. After adjusting for multiple confounders, asthma cases had higher odds of being sensitized to Der p dust mites (odds ratio [OR]=1.94, 95% confidence interval (CI): 1.13-3.35), cat (OR=1.96, 95% CI: 1.13-3.39), or dog allergens (OR=1.89, 95% CI: 1.10-3.22) than the controls. A significantly positive association between asthma status presence of cat allergen in the child's mattress (ORs: 2.61, 95% CI: 1.09-6.28) was also found. Children with both sensitization and environmental exposure to cat allergens had higher odds of asthma (OR=7.08, 95% CI: 2.12-23.62) than those who were only sensitized to cat allergen (OR=2.31, 95% CI: 1.01-5.32) or had only home exposures (OR=1.47, 95% CI: 0.47-4.65). The association between allergen sensitization and asthma was more consistent than for home exposures. The findings help to confirm the role of allergen sensitization and home exposure in regard to asthma, and suggest that both, individually and jointly, are associated with asthma.

It's time to rethink mite allergen avoidance

The role of allergen exposure in the etiology of allergic sensitization and asthma is complex. Advice on strategies to avoid domestic allergens remains contentious because trials of interventions aimed to prevent asthma or reduce symptoms have often failed to demonstrate benefits. Asthma management guidelines differ widely in their recommendations, while Web-based information often claims benefits associated with products. In this rostrum we argue that although many factors have a role in both the etiology and the exacerbation of asthma, allergen exposure probably remains an important contributor to the manifestations of the disease. Currently, there is no evidence-based framework for effective domestic allergen avoidance interventions to reduce chronic aeroallergen exposure. The development of an effective approach to allergen avoidance requires a better understanding of (a) the physical nature of chronic aeroallergen exposure and methods for measuring and reducing this, (b) the interaction between allergen exposure and innate immune modulators at different disease stages, and (c) markers enabling the identification of individuals who would benefit from this. The strategic risk of overemphasizing other novel mechanisms and approaches to asthma management is that we will prematurely abandon and fail to improve an existing approach that could have a significant impact on the development, progression, and symptoms of the disease.

House dust mite sensitization in toddlers predicts current wheeze at age 12 years

BACKGROUND

Identification of children at risk of developing asthma provides a window of opportunity for risk-reducing interventions. Allergen sensitization might identify high-risk children.

OBJECTIVE

We sought to determine whether skin prick tests (SPTs) to individual allergens up to age 2 years predict wheeze at age 12 years.

METHODS

In a birth cohort of 620 children oversampled for familial allergy, sensitization was assessed by using SPTs (monosensitized, polysensitized, or either) to 6 allergens at ages 6, 12, and 24 months. Wheeze and eczema were recorded 18 times during the first 2 years. Current wheeze was recorded at age 12 years. Adjusted associations were evaluated by multiple logistic regression.

RESULTS

A positive SPT to house dust mite (HDM) at age 1 or 2 years predicted wheeze at age 12 years (adjusted odds ratio: 1 year, 3.31 [95% CI 1.59-6.91]; 2 years, 6.37 [95% CI, 3.48-11.66]). Among wheezy 1-year-olds, those who were HDM sensitized had a 75% (95% CI, 51% to 91%) probability of wheeze at age 12 years compared with a 36% (95% CI, 23% to 50%) probability among those not sensitized. Among eczematous 1-year-olds, those who were HDM sensitized had a 67% (95% CI, 45% to 84%) probability of wheeze at age 12 years compared with a 35% (95% CI, 25% to 45%) probability among those not sensitized. Among 1-year-old children with both eczema and wheeze, the probability of wheeze at age 12 years was 64% (95% CI, 35% to 87%) if HDM sensitized and 50% (95% CI, 26% to 74%) if not.

CONCLUSION

HDM sensitization at age 1 or 2 years in wheezing and eczematous children at increased familial allergy risk predicts asthma and may inform management of these high-risk groups.

Early protective and risk factors for allergic rhinitis at age 4½ yr

Allergic heredity plays a major role in the development of allergic rhinitis. In addition the introduction of food may influence the risk of subsequent allergic disease. The aim of this study was to analyse early risk factors and protective factors for allergic rhinitis at preschool age. Data were obtained from a prospective, longitudinal study of a cohort of children born in the region of western Sweden in 2003 and 8,176 families (50% of the birth cohort) were randomly selected. The parents answered questionnaires at 6 and 12 months and at 4½ yr of age. The response rate at 4½ yr was 4,496, i.e. 83% of the 5,398 questionnaires distributed at 4½ yr. At 4½ yr of age, 5.5% reported symptoms of allergic rhinitis during the last year. In the multivariate analysis, independent risk factors for allergic rhinitis were: allergic sensitisation to food allergens at 4½ yr (OR 10.21; 95% confidence interval 4.22-24.73), recurrent wheeze at 4½ yr (3.33; 1.56-7.10), doctor-diagnosed eczema at 4½ yr (2.72; 1.62-4.55), parental rhinitis (2.21; 1.39-3.53), eczema first year (1.97; 1.19-3.26) and male gender (1.82; 1.13-2.94). The risk was reduced with fish introduction before 9 months (0.49; 0.29-0.82). In conclusion, we found that previous and present allergic disease, heredity and male gender increased the risk of allergic rhinitis at 4½ yr of age. The introduction of fish before the age of 9 months reduced the risk.

Recent perspectives on the global epidemiology of childhood eczema

The International Study of Asthma and Allergies in Childhood (ISAAC) is the largest epidemiological study ever performed and the only truly global allergy study. This review summarises the childhood eczema-related findings from ISAAC and discusses how these fit into our current understanding of eczema aetiology, with particular emphasis on worldwide time trends in eczema prevalence, climatic and dietary risk factors, breastfeeding, the role of skin barrier impairment and allergic sensitisation.

Asthma prediction in school children; the value of combined IgE-antibodies and obstructive airways disease severity score

BACKGROUND

Allergic sensitisation increases the risk for asthma development. In this prospective birth cohort (Environment and Childhood Asthma) study, we hypothesized that combining quantitative measures of IgE antibodies (Sigma-IgE) and Severity score of obstructive airways disease (OAD) at 2 years of age (Severity score) is superior to predict current asthma (CA) at 10 years than either measure alone. Secondarily, we assessed if gender modified the prediction of CA.

METHODS

A follow-up study at 10 years of age was performed in 371 2-year-old children with recurrent (n = 219) or no (n = 152) bronchial obstruction with available serum analysed for Sigma-IgE to common food and inhalant allergens through a panel test, Phadiatop Infant) (Phadia, Uppsala, Sweden). Clinical variables included allergic sensitisation and exercise testing to characterise children with CA vs not CA at 10 years and the Severity score (0-12, 0 indicating no OAD) was used to assess risk modification.

RESULTS

Severity score alone explained 24% (Nagelkerke R(2) = 0.24) of the variation in CA, whereas Sigma-IgE explained only 6% (R(2) = 0.06). Combining the two increased the explanatory capacity to R(2) = 0.30. Gender interacted significantly with Sigma-IgE; whereas Severity score predicted CA in both genders, the predictive capacity of Sigma-IgE for CA at 10 years was significant in boys only.

CONCLUSION

Combining Sigma-IgE to inhalant allergens and Severity score at 2 years was superior to predict asthma at 10 years than either alone. Severity score predicted CA in both genders, whereas Sigma-IgE significantly predicted CA in boys only.

Dietary carotenoids inhibit oral sensitization and the development of food allergy

Type-I allergic disorders and particularly food hypersensitivities are becoming increasingly common worldwide. This study investigated whether dietary enrichment with carotenoids inhibited oral sensitization to an antigen and the development of food allergies. The effects of a diet high in carotenoids were investigated in B10A mice that were orally sensitized to ovalbumin (OVA). The serum titers of OVA-specific immunoglobulin E (IgE), IgG1, and IgG2a were inhibited in mice fed ad libitum on a diet high in alpha- or beta-carotene compared to the control mice when orally sensitized to OVA. High alpha- and beta-carotene diets inhibited the immediate reduction in body temperature and rise in serum histamine associated with active systemic anaphylaxis in OVA-sensitized B10A mice. After re-stimulation with OVA in vitro, the production of T-helper 2-type cytokines by splenocytes from mice fed a diet high in carotenoids was lower than in control mice. Furthermore, the proportion of CD4(+) CD103(+) T cells in Peyer's patches of mice fed a carotenoid-rich diet was significantly lower than in control mice. These results suggest that an increased oral intake of carotenoids inhibits OVA-specific IgE and IgG1 production and antigen-induced anaphylactic responses by inhibiting specific T-cell activation in the mucosal immune system. A diet high in carotenoids might therefore prevent the development of food allergies.

Cat sensitization identified by recombinant Fel d 1 several years before symptoms--results from the BAMSE cohort

Exposure to cat is one of the most important causes of allergic disease. The objective of this study was to investigate IgE reactivity to the recombinant major cat allergen, rFel d 1, as an early marker of cat sensitization. Based on questionnaires, 144 children with allergic symptoms due to cat, or where such symptoms were suspected, were selected from the birth cohort BAMSE and allocated into three study groups. Blood samples taken at age 4 and 8 yrs were analysed for IgE to rFel d 1 and cat dander extract (CDE) by quantitative ELISA (cut-off limit 0.037 kU(A)/l) and the ImmunoCAP System (cut-off limit 0.35 kU(A)/l), respectively. At 4 yrs, 25/33 children with certain allergic symptoms to cat had IgE to both rFel d 1 and CDE, while 14/42 of those suspecting symptoms at 4 had IgE to rFel d 1 and 9/42 to CDE. In a group developing symptoms after 4 yrs, 60/69 had IgE to rFel d 1 and 57/69 to CDE at 8, while 33/69 had IgE to rFel d 1 already at 4 and 26/69 to CDE. This was the only one of the three study groups where a significant increase in the IgE levels to rFel d 1 was found from 4 to 8 yrs (p < 0.001), even when only children with IgE to rFel d 1 already at 4 were included (p < 0.001). We show that the single major cat allergen rFel d 1 is at least as good as CDE in the diagnosis of cat allergy in childhood. With a sensitive rFel d 1 assay cat sensitization can be detected several years before symptoms to cat are reported.

Allergy related disorders among 2-yrs olds in a general population. The PACT Study

Allergic disorders represent a major health problem in most developed countries, but few population-based studies have focused on these disorders in early childhood. The aims of the present study were to investigate the prevalence, gender differences and distribution of allergy related disorders and their association to sensitization among unselected children, 2 yrs of age, in a general population. A population-based study with parental self reported questionnaire data involving allergy related symptoms and results from allergy tests from 4783 two-yr-old children was conducted, and skin prick tests (SPT) of a randomly selected sample comprising 390 children were performed. In the total population the prevalence of reported wheeze was 26%, doctor diagnosed asthma (DDAsthma) 7.0%, atopic dermatitis (AD) 17% and allergic rhinoconjunctivitis (ARC) 3%. Of the 1008 (21%) allergy tested children 59% reported a positive test, but of the randomly selected children only 8% had a positive SPT. Children with AD were most frequently sensitized and children with ARC were most likely to have other allergy related disorders (70%). More boys than girls had an allergy related disorder or a positive allergy test. In conclusion, two in five had an allergy related disorder, but less than 10% had a positive SPT. Having one allergic disorder, especially ARC, increased substantially the risk of having another, and having AD was most strongly associated to a positive allergy test. Moreover, boys were more likely than girls to have an allergy related disorder or a positive SPT indicating a gender difference in the natural history of allergy related disorders.