Manifestation of atopy is not related to patient's month of birth

Birth Month and Prevalence of Atopic Dermatitis in Children Under 3 Years in Antananarivo, Madagascar

Background

Several studies have been done to evaluate the relationship between month of birth and atopic diseases but the results are contradictory.

Objective

We aim to evaluate the correlation between the month of birth and the prevalence of AD in Malagasy children less than 3 years.

Methods

A case-control study was conducted based on patients’ data of the department of Dermatology in the University Hospital Joseph Raseta Befelatanana (UH/JRB) Antananarivo. It included 438 children less than 3 years seen in this department between January 2010 and December 2019. For each atopic dermatitis (AD) patient, two age-and sex-matched controls without a history of AD were selected from the same period.

Results

This study included 146 AD cases and 292 non-AD controls. Our case-control study found that there is a statistically significant correlation between birth month and risk of AD in Malagasy children <3 years. Compared with people born in December, people born in April had the highest risk of AD (OR: 2.11, 95% CI 0.93–4.78), followed by people born in March (OR: 1.52, 95% CI 0.79–2,88). Asthma, allergic rhinitis and allergic conjunctivitis were significantly correlated with AD in our patients.

Conclusion

Our case-control study found that being born in April and March (dry season) may be associated with an increased risk of AD.

Occurrence of pollen season at the end of the first trimester predicts clinical atopic diseases in the offspring: A Finnish population-based study

OBJECTIVE

To evaluate the association between potential exposure to different pollen concentrations at the 11th fetal week and subsequent clinical atopic diseases.

STUDY DESIGN AND SETTING

Parents of 1- to 4-year-old children (N = 3035) returned a questionnaire regarding physician-diagnosed atopic diseases. The children were born between 2001 and 2005 in the province of South Karelia, Finland. Results of allergy tests were collected from patient records in the area.

RESULTS

The prevalence of atopic diseases with sensitisation was higher in children whose 11th fetal week occurred during pollen rather than non-pollen season: atopic eczema 6.3% vs. 4.3% (adjusted odds ratio, aOR 1.58, 95% CI 1.10─2.28), food allergy 5.7% vs. 3.9% (1.63; 1.12─2.38), respiratory allergy or asthma 3.7% vs. 2.2% (2.03; 1.24─3.33) and any atopic diseases 7.4% vs. 5.5% (1.48; 1.07─2.05), respectively. Respectively, the prevalence was higher in the children exposed to high rather than low tree pollen concentrations (>1000 vs. <10 particles/m³) at the 11th fetal week: 12.1% vs. 4.4% (3.35; 1.89─5.95), 12.1% vs. 3.9% (3.77; 2.11─6.72), 4.7% vs. 2.5% (2.95; 1.21─7.20) and 14.0% vs. 5.7% (3.15; 1.86─5.35).

CONCLUSION

Coincidence of potential exposure to high tree pollen concentrations at the 11th fetal week is associated with subsequent clinical atopic diseases with sensitisation.

The Association Between Season of Birth and Atopic Dermatitis in the Northern Hemisphere: A Systematic Review and Meta-Analysis

BACKGROUND

Cold and dry climate negatively affects skin barrier functions. This could explain the higher incidence of atopic dermatitis (AD) in Northern countries distant from the equator, as well as the general worsening of AD in Northern European winter months. Although it has been suggested that fall and winter birth is associated with AD, this remains unknown.

OBJECTIVES

To examine whether the prevalence of AD is associated with season of birth.

METHODS

We conducted a systematic review and meta-analysis. Two reviewers independently searched 3 databases. Study quality was assessed using a Newcastle-Ottawa scale. Study heterogeneity was assessed with Cochrane Q and I² statistics. Odds ratios with 95% CIs were calculated. Publication bias was assessed using funnel plots.

RESULTS

The systematic review identified 23 relevant articles of which 9 articles were included in the meta-analysis. Among a total of 726,378 children aged 0 to 12 years, the overall pooled prevalence of AD was 12.9%. The pooled prevalence of AD was 15.4% (95% CI, 12.1%-19.1%), 14.9% (95% CI, 12.0%-18.1%), 12.7% (95% CI, 10.2%-15.4%), and 13.7% (95% CI, 10.8%-17.0%), among children born in the fall, winter, spring, and summer, respectively. AD was significantly associated with fall (odds ratio, 1.16; 95% CI, 1.06-1.28; P = .0018) and winter (odds ratio, 1.15; 95% CI, 1.04-1.27; P = .0076) birth compared with spring birth.

CONCLUSIONS

Although a positive and significant association was observed between being born in fall and winter and developing AD on the Northern hemisphere, there is a need for additional and better-designed studies to understand the effect of seasonal changes on the risk of AD.

Are allergic multimorbidities and IgE polysensitization associated with the persistence or re-occurrence of foetal type 2 signalling? The MeDALL hypothesis

Allergic diseases [asthma, rhinitis and atopic dermatitis (AD)] are complex. They are associated with allergen-specific IgE and nonallergic mechanisms that may coexist in the same patient. In addition, these diseases tend to cluster and patients present concomitant or consecutive diseases (multimorbidity). IgE sensitization should be considered as a quantitative trait. Important clinical and immunological differences exist between mono- and polysensitized subjects. Multimorbidities of allergic diseases share common causal mechanisms that are only partly IgE-mediated. Persistence of allergic diseases over time is associated with multimorbidity and/or IgE polysensitization. The importance of the family history of allergy may decrease with age. This review puts forward the hypothesis that allergic multimorbidities and IgE polysensitization are associated and related to the persistence or re-occurrence of foetal type 2 signalling. Asthma, rhinitis and AD are manifestations of a common systemic immune imbalance (mesodermal origin) with specific patterns of remodelling (ectodermal or endodermal origin). This study proposes a new classification of IgE-mediated allergic diseases that allows the definition of novel phenotypes to (i) better understand genetic and epigenetic mechanisms, (ii) better stratify allergic preschool children for prognosis and (iii) propose novel strategies of treatment and prevention.

Continuous 6-year follow-up study of sensitization to Japanese cedar pollen and onset in schoolchildren

BACKGROUND

Intra individual longitudinal data has been lacking for IgE-mediated seasonal allergic rhinitis (SAR), especially in young children. Little is known about the development and natural course of SAR in terms of prevalence and incidence rates in schoolchildren.

METHODS

In May or June each year from 1994 to 2007, schoolchildren were assessed for serum Japanese cedar pollen (JCP)-IgE and house dust mite (HDM)-IgE levels, and surveyed regarding nasal symptoms.

RESULTS

Among the 220 children initially assessed in the first grade, 69 (31.4%) were already sensitized to JCP at first grade and 119 (54.1%) did not develop JCP sensitivity during the 6-year study at all. In the first grade children who were HDM-sensitized but JCP non-sensitized, JCP-IgE level was significantly elevated compared to the JCP and HDM non-sensitized group. This seems to indicate that HDM sensitization was very strongly associated with JCP sensitization.

CONCLUSIONS

Elevated serum IgE is a consequence of specific sensitization to HDM and HDM sensitization appeared to develop prior to the start of primary school which distinguishes HDM sensitization from JCP sensitization.

The relationship of season of birth to asthma and allergy in urban African American children from 10 to 13 years of age

OBJECTIVES

To assess the relationship between season of birth and presence of asthma and allergy in preteen, low-income, African American children.

METHODS

The study consisted of a self-administered survey followed by telephone interviews of parents of children attending 19 middle schools in Detroit, Michigan. Out of 4194 children, 1292 were identified with asthma and 962 parents of these children provided informed consent and took part in telephone interviews.

RESULTS

No statistically significant relationships were observed between season of birth and diagnosis of asthma (p > .05) or with diagnosis adjusting for income, age, gender, parent's education, or parent being a smoker (p > .05). No statistically significant association was evident between season of birth and presence of allergy (p > .05) or with allergy adjusting for the above variables (p > .05).

CONCLUSIONS

Identifying children vulnerable to problems with asthma and allergy, especially in populations exhibiting high prevalence of the conditions and significant disparities in outcomes, requires use of all possible means. Season of birth does not appear to be a useful indicator in identification of such children. The findings from this study do not support the proposition that season of birth, associated with early exposure to viruses as evident in the winter and to seasonal allergens, contributes to more asthma and/or allergy.

Potential mechanisms for the association between fall birth and food allergy

BACKGROUND

Season of birth has been reported as a risk factor for food allergy, but the mechanisms by which it acts are unknown.

METHODS

Two populations were studied: 5862 children from the National Health and Nutrition Examination Survey (NHANES) III and 1514 well-characterized food allergic children from the Johns Hopkins Pediatric Allergy Clinic (JHPAC). Food allergy was defined as self-report of an acute reaction to a food (NHANES), or as milk, egg, and peanut allergy. Logistic regression compared fall or nonfall birth between (i) food allergic and nonallergic subjects in NHANES, adjusted for ethnicity, age, income, and sex, and (ii) JHPAC subjects and the general Maryland population. For NHANES, stratification by ethnicity and for JHPAC, eczema were examined.

RESULTS

Fall birth was more common among food allergic subjects in both NHANES (OR, 1.91; 95% CI, 1.31-2.77) and JHPAC/Maryland (OR, 1.31; 95% CI, 1.18-1.47). Ethnicity interacted with season (OR, 2.34; 95% CI, 1.43-3.82 for Caucasians; OR, 1.19; 95% CI, 0.77-1.86 for non-Caucasians; P = 0.04 for interaction), as did eczema (OR, 1.47; 95% CI, 1.29-1.67 with eczema; OR, 1.00; 95% CI, 0.80-1.23 without eczema; P = 0.002 for interaction).

CONCLUSIONS

Fall birth is associated with increased risk of food allergy, and this risk is greatest among those most likely to have seasonal variation in vitamin D during infancy (Caucasians) and those at risk for skin barrier dysfunction (subjects with a history of eczema), suggesting that vitamin D and the skin barrier may be implicated in seasonal associations with food allergy.

A long-term follow-up of allergic diseases in Iceland

INTRODUCTION

Allergic disorders are an increasing health problem in many countries, in particular among children. We have evaluated the prevalence and manifestations of allergy in a cohort of young Icelanders for more than two decades. Variations in the epidemiology and clinical expression of allergy in different communities may help to identify etiological factors contributing to these disorders.

METHODS

A cohort of 179 children has been monitored for allergic manifestations for two decades, at the ages of two, four, eight, and 15 years, and most recently at the age of 21 years involving 120 of the participants.

RESULTS

Cumulative prevalences of 40%, 45%, and 29% have been observed, respectively, for rhinoconjunctivitis, eczema, and asthma during the study period. None had developed rhinoconjunctivitis at the age of about 2 years, but the point prevalence gradually increased to 33% at the age of 21 years. Conversely, the prevalence of eczema was 31% at the age of 2 years, but gradually declined to 8% at the age of 21 years. The prevalence of asthma peaked at 28% at the age of 4 years, but declined thereafter and has remained stable at about 13% from the age of eight to 21 years.

DISCUSSION

The prevalence of allergic diseases is high in Iceland among children and young individuals. Asthma and atopic eczema are very common in childhood, but decreases with age while the prevalence of rhinoconjunctivitis increases markedly. The very high and increasing prevalence of rhinoconjunctivitis among 15- to 21-year-old individuals is noteworthy.

Production of interleukin-5, -10 and interferon-γ in cord blood is strongly associated with the season of birth

BACKGROUND

The effect of labour and different labour-related factors on the cord blood (CB) cell cytokine production is still relatively unknown.

OBJECTIVE

To study the relationships between the production of IL-5, IL-10 and IFN-γ in CB samples and maternal, early neonatal and birth-related factors.

METHODS

Whole-blood samples were collected after birth (n=423) and they were stimulated for 24 and 48 h with a combination of phorbol ester and ionomycin. Production of IL-5, IL-10 and IFN-γ was determined using ELISA. Maternal, early neonatal and birth-related variables were recorded prospectively during pregnancy, and during and after delivery.

RESULTS

After multivariable adjustment for confounders, the strongest predictor of IL-5, IL-10 and IFN-γ production in CB cell samples was the season of birth. Children born in the spring had significantly lower cytokine responses compared with those born in the fall. IL-5 production was inversely associated with female gender of the child and maternal smoking. If corrections for white blood cell (WBC) counts were not performed, IL-5 production was also significantly associated with the mode of delivery. Respectively, the production of IL-10 and IFN-γ was inversely associated with prostaglandin induction before birth.

CONCLUSION

Environmental exposure to pollen and ultraviolet irradiation during gestation may have an effect on the cytokine profile of the offspring in CB because children born in the spring or winter showed the lowest IL-5, IL-10 and IFN-γ responses. The production of IL-10 and IFN-γ was also inversely associated with prostaglandin labour induction before birth. Other labour-related factors were not significantly associated with production of IL-5, IL-10 and IFN-γ after WBC count correction.

Fungi and pollen exposure in the first months of life and risk of early childhood wheezing

BACKGROUND

Many studies have found that the risk of childhood asthma varies by month of birth, but few have examined ambient aeroallergens as an explanatory factor. A study was undertaken to examine whether birth during seasons of elevated ambient fungal spore or pollen concentrations is associated with risk of early wheezing or blood levels of Th1 and Th2 type cells at 24 months of age.

METHODS

514 children were enrolled before birth and followed to 24 months of age. Early wheezing was determined from medical records, and Th1 and Th2 type cells were measured in peripheral blood using flow cytometry. Ambient aeroallergen concentrations were measured throughout the study period and discrete seasons of high spore and pollen concentrations were defined.

RESULTS

A seasonal pattern was observed, with birth in autumn to winter (the spore season) associated with increased odds of early wheezing (adjusted odds ratio 3.1; 95% confidence interval 1.3 to 7.4). Increasing mean daily concentrations of basidiospores and ascospores in the first 3 months of life were associated with increased odds of wheeze, as were increasing mean daily concentrations of total and specific pollen types. Levels of Th1 cells at age 24 months were positively associated with mean spore concentrations and negatively associated with mean pollen concentrations in the first 3 months of life.

CONCLUSIONS

Children with higher exposure to spores and pollen in the first 3 months of life are at increased risk of early wheezing. This association is independent of other seasonal factors including ambient levels of particulate matter of aerodynamic diameter <or=2.5 microm and lower respiratory infections.

Symptoms to pollen and fruits early in life and allergic disease at 4 years of age

BACKGROUND

The predictive value of reported early symptoms to pollen or fruits on later allergic disease is unclear. Our aim is to evaluate if symptoms to pollen and/or to fruits early in life are associated with allergic disease and sensitization to pollen at 4 years.

METHODS

The study included 3619 children from the Barn (Children), Allergy, Milieu, Stockholm, Epidemiology project (BAMSE) birth cohort. Reported symptoms of wheeze, sneeze or rash to birch, grass or weed, symptoms (vomiting, diarrhea, rash, facial edema, sneeze, or wheeze) to fruits including tree-nuts at 1 or 2 years of age, and definitions of asthma, rhinitis and eczema at 4 years were derived from questionnaire data. Sensitization to pollen allergens was defined as allergen-specific IgE-antibodies to any pollen (birch/timothy/mugwort) > or =0.35 kU(A)/l.

RESULTS

At 1 or 2 years of age, 6% of the children were reported to have pollen-related symptoms, 6% had symptoms to fruits, and 1.4% to both pollen and fruits. Children with symptoms to both pollen and fruits at 1 or 2 years of age had an increased risk for sensitization to any pollen allergen at age 4 (OR(adj) = 4.4, 95% CI = 2.1-9.2). This group of children also had a substantially elevated risk for developing any allergic disease (asthma, rhinitis, or eczema) at 4 years irrespective of sensitization to pollen (OR(adj) = 8.6, 95% CI = 4.5-16.4).

CONCLUSIONS

The prevalence of reported symptoms to pollen and fruits is very low in early childhood. However, children with early symptoms to both pollen and fruits appear to have a markedly elevated risk for allergic disease.

Vaccinations, infections and antibacterials in the first grass pollen season of life and risk of later hayfever

BACKGROUND

It has been hypothesized that early-life exposure to vaccinations, infections or antibacterials influence allergic disease development. Concurrent exposure to grass pollens may alter any effect.

OBJECTIVE

To test the hypothesis that exposure to antibacterials, vaccinations (DTP or MMR) or specific infections during the first grass pollen seasons of life influences the risk of hayfever more than at any other time of the year.

METHODS

Nested case-control studies were based on birth cohorts within two large databases of computerized patient records from UK general practices: the General Practice Research Database (GPRD) and Doctors' Independent Network (DIN). Seven thousand ninety-eight hayfever cases, diagnosed after age 2, were matched to controls for practice, age, sex and follow-up of control to case ascertainment date. Conditional logistic regression was used to compare exposure by age 1 (age 2 for MMR) inside vs. outside the grass pollen season (May, June, July). Odds ratios (ORs) were pooled across databases.

RESULTS

There were no associations in either database between MMR during vs. outside the grass pollen season and later hayfever. Of 23 infections studied, none were statistically significant; although analyses for the less common conditions were limited by low statistical power. The pooled OR for hayfever comparing exposure to antibacterials only in the grass pollen season with only outside it was 1.20 (95% CI 0.98-1.47) and for DTP was 0.84 (95% CI 0.72-0.98).

CONCLUSION

Although an interaction between early exposure to microbial agents and concurrent grass pollen exposure on hayfever risk seemed plausible, there was little evidence to support it across a range of analyses. However, the effect of DTP though weak deserves further study.

Season of birth and risk of atopic disease among children and adolescents

BACKGROUND

Season of birth (SOB) has been regarded as a risk factor for atopy. The aim of this study was to explore the relationship between season of birth (SOB) and later development of atopic disease in children and adolescents.

METHODS

A total of 1,007 randomly selected subjects, 7 to 17 years of age, who were living in urban Copenhagen, Denmark were studied. All participants were interviewed about respiratory symptoms and possible risk factors for atopic disease. Skin test reactivity, serum total immunoglobulin E (IgE), and airway responsiveness were measured using standard techniques.

RESULTS

The overall risk of atopy, as judged by skin test reactivity and serum total IgE, was the same regardless of SOB. On the contrary, asthma was more common in subjects born in the autumn compared with subjects born during the remaining part of the year (12.4% vs. 5.6%), OR = 2.40, 95% CI (1.56-3.94), p < 0.001. This was observed both for atopic asthma OR = 2.41, 95% CI (1.25-4.64), p = 0.007, non-atopic asthma, OR = 2.35, 95% CI (1.14-4.83), p = 0.02, and house dust mite (HDM) sensitive airway hyperresponsiveness, OR = 3.00, 95% CI (1.44-6.24), p = 0.002. Rhinitis and pollen allergy were not significantly related to SOB.

CONCLUSIONS

Atopy itself is independent of season of birth, whereas asthma is more prevalent among subjects born during the autumn. Regarding asthma, these results suggest that the first months of life enclose a period of particular vulnerability towards environmental risk factors, especially exposure to aeroallergens like HDM.

Before-birth climatologic data may play a role in the development of allergies in infants

While an exacerbation in allergic symptoms corresponding to seasons has long been reported, few studies have investigated the association between the season of birth and allergic disorders. The aim of this study was to investigate whether the climatologic data before and after birth affected the incidence of atopic dermatitis (AD) and the results of allergy-related blood tests in early infancy. From February 1995 to January 2000, 2136 infants were tested for AD and followed for 12 months. AD patients were tested by using allergy-related blood tests. Data were compared according to the month of birth and the climatologic data using a computed statistical software package. Six hundred and thirty infants had AD before 12 months old, and significant differences were found according to the season of birth (p < 0.0001). Infants born in spring showed the lowest (22.3%) incidence, while those born in autumn showed the highest (34.6%). In 369 patients, total serum IgE levels, and serum specific IgE levels with egg white at 3 months old were also different according to the season of birth. All of these levels were lower in patients born in spring and summer, and higher in patients born in autumn and winter. Furthermore, the cumulative sunshine amount during the 3 months before and after birth was inversely correlated, while the average temperature over the 3 months before birth was positively correlated to the incidence of AD according to the month of birth. The climatologic data around birth may play an important role in whether an infant develops allergies.

Birth month and sensitization to house dust mites in asthmatic children

BACKGROUND

Early exposure to high quantities of allergen has an important role in the incidence of atopic sensitization. In fact, subjects sensitized to house dust mites (HDMs) have a significantly higher proportion of births in the season when HDMs are most abundant.

OBJECTIVE

The aim of this study was to investigate whether birth month patterns differ for asthmatic patients sensitized only to HDMs and for those sensitized to HDMs and other allergen(s).

METHODS

Among 2225 patients with asthma, aged 10-16 years, 1642 sensitized to HDMs were identified by skin prick testing. This group was composed of patients sensitized only to HDMs (n = 715) and patients sensitized to HDMs and other allergen(s) (n = 927). The birth month distributions of the group of HDM-sensitive asthmatics or its subgroups were compared with that of a reference population (total live births in the same years as the studied subjects). The risk ratio of a given birth month in relation to all the other months was calculated as an odds ratio (OR) with the corresponding 95% confidence interval (CI).

RESULTS

A significant difference in birth month distribution was observed for HDM-sensitive asthmatics (chi(2) = 23.6, P = 0.015), with higher rates of birth in August (OR: 1.23, 95% CI: 1.04-1.46) and September (1.24, 1.04-1.46). When the two subgroups were analyzed separately, significantly more births were noted in August (1.34, 1.06-1.71) and September (1.34, 1.05-1.70) for those sensitized only to HDMs, whereas no such birth month preference was observed for those sensitized to HDMs and other allergen(s).

CONCLUSIONS

The HDM-positive asthmatics showed a greater proportion of births in August and September, which correspond to high HDM exposure. However, this birth month pattern was evident in asthmatic-sensitive only to HDMs, but was not observed in those sensitive to HDMs and other allergen(s).

Latitude, birth date, and allergy

BACKGROUND

The space and time distribution of risk factors for allergic diseases may provide insights into disease mechanisms. Allergy is believed to vary by month of birth, but multinational studies taking into account latitude have not been conducted.

METHODS AND FINDINGS

A questionnaire was distributed in 54 centres to a representative sample of 20- to 44-y-old men and women mainly in Europe but also including regions in North Africa, India, North America, Australia, and New Zealand. Data from 200,682 participants were analyzed. The median prevalence of allergic rhinitis was 22%, with a substantial variation across centres. Overall, allergic rhinitis decreased with geographical latitude, but there were many exceptions. No increase in prevalence during certain winters could be observed. Also, no altered risk by birth month was found, except borderline reduced risks in September and October. Effect estimates obtained by a multivariate analysis of total and specific IgE values in 18,085 individuals also excluded major birth month effects and confirmed the independent effect of language grouping.

CONCLUSION

Neither time point of first exposure to certain allergens nor early infections during winter months seems to be a major factor for adult allergy. Although there might be effects of climate or environmental UV exposure by latitude, influences within language groups seem to be more important, reflecting so far unknown genetic or cultural risk factors.

Categorization of patients with allergic rhinitis: a comparative profile of "sneezers and runners" and "blockers"

BACKGROUND

The recent Allergic Rhinitis and Its Impact on Asthma (ARIA) workshop report classified patients into "sneezers and runners" and "blockers" and described a new disease severity categorization.

OBJECTIVE

To sketch the profile of these 2 groups and to evaluate the relevance of categorization.

METHODS

Patients were categorized as "sneezers and runners" (group 1) or "blockers" (group 2). The patients responded to a questionnaire that sought information on symptoms and associated factors. They were then categorized into seasonal allergic rhinitis (SAR) and perennial allergic rhinitis (PAR) groups and "intermittent" and "persistent" disease groups and compared.

RESULTS

A total of 114 patients (72 in group 1 and 42 in group 2) participated in the study. The significant features in group 1 were age at onset younger than 20 years (90%); birth date between June and September (61%); family history of atopy (88%); itching of skin (26%), eye (43%), ears (43%), and throat and palate (67%); and aggravation with dust (93%). History of breathlessness (90%), mouth breathing (81%), loss of smell (36%), and prior nasal surgery (31%) were significant in group 2. Significantly more patients in group 1 had SAR (54%) and moderate-severe intermittent disease (60%), whereas group 2 had PAR (81%) and mild persistent (69%) disease (P = .03). Patients classified as having SAR had intermittent disease (40, 83%) (P = .005), and those with PAR had persistent disease (51, 76%) (P < .001). Sixteen patients (24%) classified as having PAR were in the intermittent category, whereas 7 (17%) classified as having SAR were in the persistent category.

CONCLUSIONS

This study demonstrated that the 2 groups had distinct clinical profiles and that it is important to categorize patients, according to the ARIA report, into intermittent and persistent allergic rhinitis groups.

Exposure to birch pollen in infancy and development of atopic disease in childhood

BACKGROUND

The relationship between early allergen exposure, sensitization, and development of atopic disease remains controversial. In 1993, extremely high levels of birch pollen were recorded in Stockholm, Sweden, creating the unique opportunity to study children with different exposures during infancy.

OBJECTIVE

We sought to assess the influence of early high-dose exposure to an inhalant allergen (birch pollen) on sensitization and development of atopic disease in children.

METHODS

A total of 583 children with atopic heredity born in Stockholm in February through April 1992, 1993, or 1994 were investigated at age 4.5 to 5 years. The children were examined and underwent skin prick testing with inhalant and food allergens. IgE antibodies (RAST) against birch pollen and recombinant birch pollen allergen (rBet v 1) were analyzed in serum.

RESULTS

The children born in 1993 (high-dose exposure at 0-3 months) were more often sensitized (ie, positive skin prick test response) to birch pollen than the children born in 1994 (low-dose exposure; 17.8% and 8.8%, respectively; odds ratio [OR], 2.4; 95% CI, 1.2-4.6). A tendency in the same direction was seen for children born in 1992 (high-dose exposure at 12-15 months; OR, 1.7; 95% CI, 0.9-3.2). The results were supported by the RAST analyses. The prevalence of bronchial asthma, allergic rhinoconjunctivitis, and atopic dermatitis did not differ between the birth-year groups. However, the prevalence of pollen- and animal dander-induced allergic asthma was increased in the children born in 1993 (OR, 2.6; 95% CI, 1.2-5.6). An interaction between early high-dose exposure to birch pollen and cat in the household was suggested for sensitization to cat (P =.06).

CONCLUSION

Exposure to high levels of birch pollen in infancy increases the risk of sensitization to the same allergen, as well as the risk of allergic asthma.

Development of seasonal allergic rhinitis during the first 7 years of life

BACKGROUND

Against the background of the controversial discussion about an increase in allergic rhinitis in recent years, intraindividual longitudinal data is lacking for IgE-mediated seasonal allergic rhinitis (SAR). Little is known about the development of SAR in terms of prevalence and incidence rates from birth to school age.

OBJECTIVE

In a prospective birth cohort, we investigated the development of sensitization and symptoms of SAR. SAR should be defined with high specificity, and associated risk factors should be determined.

METHODS

Annual longitudinal data about seasonal allergic symptoms and sensitization was available for 587 children from birth to their seventh birthday. The definition of SAR was based on a combination of exposure-related symptoms and sensitization.

RESULTS

Up to 7 years of age, SAR developed in 15% of the children. Incidence and prevalence of symptoms and sensitization were low during early childhood (<2%) and increased steadily with age. Children in which SAR had already developed in the second year all were born in spring or early summer, resulting in at least two seasons of pollen exposure before manifestation of SAR. Risk factors assessed by multiple logistic regression analysis were male sex (odds ratio [OR] = 2.4), atopic mothers (OR = 2.6) and fathers (OR = 3.6) having allergic rhinitis themselves, first-born child (OR = 2.0), early sensitization to food (OR = 3.3), and atopic dermatitis (OR = 2.5), whereas early wheezing was not associated with SAR.

CONCLUSION

The development of SAR is characterized by a marked increase in prevalence and incidence after the second year of life. Our longitudinal data further indicate that in combination with the risk of allergic predisposition, at least 2 seasons of pollen allergen exposure are needed before allergic rhinitis becomes clinically manifest.

Prevalence of atopy in students from Málaga, Spain

BACKGROUND

Epidemiologic studies are necessary to determine the prevalence of allergic diseases. This varies widely depending on allergen preparations and patients studied.

OBJECTIVE

To investigate the prevalence of atopic disease, skin test reactivity, total and specific IgE to common allergens, and other variables in a sample of students from Málaga, southern Spain.

METHODS

Three hundred sixty-five students (age 17.9 +/- 1.18) were interviewed by an allergist. Skin prick tests were performed with Dermatophagoides pteronyssinus, Artemisia vulgaris, Plantago lanceolata, Chenopodium album, Olea europaea, Phleum pratense, Parietaria judaica, Cynodon dactylon, Alternaria tenuis, and cat dander. Total and specific IgE to D. pteronyssinus, Olea, and Parietaria were determined.

RESULTS

Of all subjects studied, 19.9% suffered from rhinoconjunctivitis, 4.1% rhinoconjunctivitis plus asthma, 3.1% asthma alone, and 0.8% atopic dermatitis; 46.4% had a positive skin test to at least one allergen (28.2% to D. pteronyssinus, 20.4% to Olea, 13.8% to Phleum); and 43% had total IgE > 100 kU/L and 44.7% a family history of atopy. Allergic symptoms were strongly associated with skin test positivities and family allergic history. Patients with asthma or skin prick test positive had higher total IgE values than others (P < .01). There was a significant correlation between specific IgE values and wheal size in skin test.

CONCLUSIONS

Our findings confirm the high prevalence of atopic diseases, and the close relationship of skin tests reactivity (or presence of specific IgE) to allergens with symptoms of asthma and rhinitis. The presence of a family history of allergic diseases influences the development of positive skin tests and atopic illness. Dermatophagoides pteronyssinus and pollen of Olea europaea were found to be the most common allergens.

Kiwi fruit allergy: a new birch pollen-associated food allergy

BACKGROUND

To determine the cross-reacting antigens of kiwi fruit and other foods and pollen, we investigated 22 patients allergic to kiwi fruit: 10 with severe systemic reactions and 12 with localized symptoms confined to oral and pharyngeal mucosa (oral allergy syndrome). Seven patients with birch pollen allergy who tolerated kiwi fruit were included as a control group.

METHODS

All patients were evaluated by skin testing and RAST; three patients were evaluated by RAST inhibition assays.

RESULTS

Prick tests showed positive reactions to kiwi fruit in all patients, whereas specific IgE to kiwi fruit could be demonstrated only in patients with generalized severe symptoms. Surprisingly, all 22 patients with clinical kiwi allergy showed positive prick test results and elevated IgE to birch pollen. Clinically, all complained of rhinitis during birch pollen season. Many patients showed sensitization to grass and mugwort pollen. Also, food allergy was found to be associated with kiwi allergy: we found strong reactions to apple and hazelnut; moderate reactions to carrot, potato, and avocado; and weak reactions to wheat and rye flour, pineapple and papaya, and their enzymes bromelain and papain. RAST inhibition studies revealed cross-reacting antigens between birch pollen and kiwi fruit. Interestingly, patients with birch pollen allergy without clinical signs of kiwi allergy had positive prick test reactions to kiwi. Patients with kiwi allergy showed higher concentrations to birch pollen IgE compared with patients with isolated birch pollen allergy.

CONCLUSIONS

Our results indicate that kiwi allergy is a new manifestation of birch pollen-associated food allergy and is mediated by cross-reacting antigens in the kiwi fruit. Kiwi allergy can be expected in patients with birch pollen allergy exhibiting high levels of IgE to birch pollen.