Epidemiology of food allergy/food intolerance in adults: associations with other manifestations of atopy

BACKGROUND: Food allergy and food intolerance (FA/FI) are believed to be frequent medical problems; however, information from epidemiologic studies in adults is scarce. The objective was to determine the frequency of FA/FI and allergic sensitization to food in a large adult sample. Furthermore, the associations between FA/FI and other outcomes of atopy were studied. METHODS: Within a population-based, nested, case-control study, a standardized interview was performed to obtain detailed information on FA/FI and the history of atopic diseases. In addition, a skin prick test with 10 common food and nine aeroallergens was performed. RESULTS: Overall, 20.8% of the 1537 studied subjects (50.4% female, age median 50 years) reported FA/FI (women 27.5%, men 14.0%; OR 2.35, CI 1.80-3.08). Nuts, fruits, and milk most frequently led to adverse effects, and the sites of manifestation were oral (42.9%), skin (28.7%), gastrointestinal (13.0%), systemic (3.2%), and multiple (12.2%). One-quarter of the subjects (25.1%) were sensitized to at least one food allergen in the prick test, with hazelnut (17.8%), celery (14.6%), and peanut (11.1%) accounting for most of the positive reactions. The corresponding frequency estimates for the representative study base (n=4178) were 15.5% for reported adverse reactions and 16.8% for allergic sensitization. Relevant concomitant sensitization to food and aeroallergens was observed. Food-allergic subjects (positive history and sensitization to corresponding allergen) suffered significantly more often from urticaria, asthma, atopic eczema, and especially hay fever (73.1%) than controls (3.0%). Furthermore, hay fever was treated significantly more often in subjects who suffered from concomitant food allergy. CONCLUSIONS: FA/FI in adults is frequently reported and associated with other manifestations of atopy. Hay fever in conjunction with FA/FI tends to be clinically more severe since therapeutic needs are enhanced.     

Association between sensitized to food allergens and childhood allergic respiratory diseases in Taiwan

BackgroundSensitization to allergen has long been known to be relate to childhood allergic diseases. Polysensitised children have more severe atopic diseases, whereas allergic rhinitis or asthma children with cosensitized to food and inhalant allergens were under-researched.ObjectiveTo realize the association between sensitization to food allergens and pediatric allergic rhinitis and asthma in Taiwan.MethodsWe included 138 participants with sensitized to allergen as assessed by serum-specific IgE. 87 of 138 participants had allergic rhinitis and 51 participants had asthma. All participants underwent a physical examination and measurement of serum total and specific IgE values. Besides, nasal peak expiratory flow rate (nPEFR) that was performed by the participants with allergic rhinitis and were requested to complete the Pediatric Rhinoconjunctivitis Quality of Life Questionnaires (PRQLQ). Lung function test and asthma control test (ACT)/child asthma control test (C-ACT) were performed by the participants with asthma.Results39 of 87 allergic rhinitis participants with sensitized to food and inhalant allergens (AR food group), 48 of 87 allergic rhinitis participants with sensitized to inhalant allergen alone (AR inhalant group). The AR food group had significantly lower nPEFR values and higher total IgE values (p < 0.05) compared with the AR inhalant group. The AR food group had higher PRQLQ scores than the AR inhalant group. 24 of 51 asthma participants with sensitized to food and inhalant allergens (Asthma food group), 27 of 51 asthma participants with sensitized to inhalant allergen alone (Asthma inhalant group). The Asthma food group had significantly higher total IgE values (p < 0.05) compared with the Asthma inhalant group. The Asthma food group had lower lung function test values and asthma control test (ACT) scores than the other group.ConclusionsChildren with cosensitized to food and inhalant allergens have more severe clinical symptoms and abnormal laboratory findings. Sensitization to food allergen was more related to pediatric allergic rhinitis than asthma. We may need larger, longer and extended studies to confirm these findings.     

Degree and clinical relevance of sensitization to common allergens among adults: a population study in Helsinki, Finland

BACKGROUND: We aimed to assess the prevalence of allergic sensitization and multiple sensitization, risk factors, and the clinical impact of being sensitized in the adult population of Helsinki, Finland. METHODS: As a part of the FinEsS study, a population-based random sample of 498 adults aged 26-60 years were tested for 15 common aeroallergens with skin prick tests (SPTs) and interviewed on respiratory symptoms and diseases, including respiratory irritants and childhood environment. RESULTS: The prevalence of at least one positive prick test was 46.9%. A large difference by age was found: 56.8% were sensitized among those aged 26-39 years, 49.2% in the age group 40-49 years, and 35.6% in the age group 50-60 years (P<0.001). Sensitization to multiple allergens was common among young subjects with 42% of the sensitized responding to at least four allergens, while this proportion was only 16% of the sensitized among those aged 50-60 years. The prevalence of physician-diagnosed asthma, allergic rhinitis (AR) or conjunctivitis, and wheeze increased significantly with increasing number of positive responses to SPTs. Having a family history of AR or conjunctivitis was a significant risk factor for allergic sensitization and for sensitization to any of the pollens. Further, urban living in childhood yielded an increased risk for pollen sensitization. CONCLUSIONS: The prevalence of allergic sensitization was high in the urban adult population of Helsinki. More than half of those aged 26-39 years was sensitized and 24% was sensitized to at least four allergens. Sensitization to multiple allergens was associated with a high prevalence of asthma, AR or conjunctivitis, and wheeze.     

Long-term exposure to background air pollution related to respiratory and allergic health in schoolchildren

BACKGROUND: The impact of air pollution on asthma and allergies still remains a debate. OBJECTIVE: Our cross-sectional study was intended to analyse the associations between long-term exposure to background air pollution and atopic and respiratory outcomes in a large population-based sample of schoolchildren. METHODS: Six thousand six hundred and seventy-two children aged 9-11 years recruited from 108 randomly schools in six French cities underwent a clinical examination including a skin prick test (SPT) to common allergens, exercise-induced bronchial reactivity (EIB) and skin examination for flexural dermatitis. The prevalence of asthma, allergic rhinitis (AR) and atopic dermatitis was assessed by a standardized health questionnaire completed by the parents. Three-year-averaged concentrations of air pollutants (NO2, SO2, PM10 and O3) were calculated at children' schools using measurements of background monitoring stations. RESULTS: After adjusting for confounders, EIB, lifetime asthma and lifetime AR were found to be positively related to an increase in the exposure to SO2, PM10 and O3. The adjusted odds ratios (aOR) per increase of 5 microg/m3 of SO2 was 1.39 (95% confidence interval (CI)=1.15-1.66) for EIB and 1.19 (1.00-1.41) for lifetime asthma. The aOR for lifetime AR per increase of 10 microg/m3 of PM10 was 1.32 (CI=1.04-1.68). Moreover, SPT positivity was associated with O3 (aOR=1.34; CI=1.24-1.46). Associations with past year symptoms were consistent, even if not always statistically significant. Results persisted in long-term resident (current address for at least 8 years) children. However, no consistent positive association was found with NO2. CONCLUSIONS: A moderate increase in long-term exposure to background ambient air pollution was associated with an increased prevalence of respiratory and atopic indicators in children.     

Familial aggregation of food allergy and sensitization to food allergens: a family-based study

Background The increasing prevalence of food allergy (FA) is a growing clinical and public health problem. The contribution of genetic factors to FA remains largely unknown. Objective This study examined the pattern of familial aggregation and the degree to which genetic factors contribute to FA and sensitization to food allergens. Methods This study included 581 nuclear families (2,004 subjects) as part of an ongoing FA study in Chicago, IL, USA. FA was defined by a set of criteria including timing, clinical symptoms obtained via standardized questionnaire interview and corroborative specific IgE cut‐offs for 95% positive predictive value (PPV) for food allergens measured by Phadia ImmunoCAP. Familial aggregation of FA as well as sensitization to food allergens was examined using generalized estimating equation (GEE) models, with adjustment for important covariates including age, gender, ethnicity and birth order. Heritability was estimated for food‐specific IgE measurements. Results FA in the index child was a significant and independent predictor of FA in other siblings (OR=2.6, 95% CI: 1.2–5.6, P=0.01). There were significant and positive associations among family members (father–offspring, mother–offspring, index–other siblings) for total IgE and specific IgE to all the nine major food allergens tested in this sample (sesame, peanut, wheat, milk, egg white, soy, walnut, shrimp and cod fish). The estimated heritability of food‐specific IgE ranged from 0.15 to 0.35 and was statistically significant for all the nine tested food allergens. Conclusion This family‐based study demonstrates strong familial aggregation of FA and sensitization to food allergens, especially, among siblings. The heritability estimates indicate that food‐specific IgE is likely influenced by both genetic and environmental factors. Together, this study provides strong evidence that both host genetic susceptibility and environmental factors determine the complex trait of IgE‐mediated FA.     

Atopy and house dust mite sensitization as risk factors for asthma in children

BACKGROUND: Recent evidence suggests that asthma is not invariably related to atopy. The aim of this study was to evaluate the frequency of atopy, asthma and sensitization to eight common allergens in a large group of children with allergic symptoms. METHODS: 1426 children referred to our Paediatric Asthma and Allergy Center because of allergic symptoms were examined. Bronchial asthma, allergic rhino-conjunctivitis, food allergy and atopic dermatitis were diagnosed with standardized methods. Atopy was diagnosed if at least one skin test was positive. RESULTS: Of the 1426 children examined, 629 (44%) were atopic and 769 (56%) were non-atopic. Asthma was diagnosed in the same proportion (i.e., 64%) of atopic and non-atopic children. However, after division into age groups, non-atopic asthma was significantly more prevalent (chi2 = 8.46) in children between 0 and 3 years old (group 1). On the other hand, atopy was significantly associated with asthma only in group 3 (odds ratio 1.85). Furthermore, a significant association with asthma symptoms was found for house dust mite (HDM) in group 3 (odds ratio 4.8). CONCLUSIONS: Asthma is related to atopy in pre-selected children only from the age of 7 years. House dust mite sensitization seems to be an important determinant of asthma in these "older" children.     

Food allergy is associated with an increased risk of asthma

Background The atopic march is well documented, but the interrelationship of food allergy (FA) and asthma is not well understood.
Objective The aim of this study was to examine the strength of the association and temporal relationships between FA and asthma.
Methods This analysis included 271 children 6 years (older group) and 296 children <6 years (younger group) from a family-based FA cohort in Chicago, IL. Asthma was determined by parental report of physician diagnosis. FA status was determined based on the type and timing of clinical symptoms after ingestion of a specific food, and results of prick skin test (Multi-Test II) and allergen-specific IgE (Phadia ImmunoCAP). Analyses were carried out using logistic regression accounting for important covariates and auto-correlations among siblings. Kaplan–Meier curves were used to compare the time to onset of asthma with the FA status.
Results Symptomatic FA was associated with asthma in both older [odds ratio (OR)=4.9, 95% confidence interval (CI): 2.5–9.5] and younger children (OR=5.3, 95% CI: 1.7–16.2). The association was stronger among children with multiple or severe food allergies, especially in older children. Children with FA developed asthma earlier and at higher prevalence than children without FA (Cox proportional hazard ratio=3.7, 95% CI: 2.2–6.3 for children 6 years, and hazard ratio=3.3, 95% CI: 1.1–10 for children <6 years of age). No associations were seen between asymptomatic food sensitization and asthma.
Conclusions Independent of markers of atopy such as aeroallergen sensitization and family history of asthma, there was a significant association between FA and asthma. This association was even stronger in subjects with multiple food allergies or severe FA.     

Atopic characteristics of children with recurrent wheezing at high risk for the development of childhood asthma

BACKGROUND: Few studies have characterized the atopic profile of toddler-aged children with recurrent wheezing at high risk of the development of persistent asthma. Objective We sought to determine the atopic profile of toddler-aged children with frequent wheeze at high risk for the development of persistent asthma who either had a parental history of asthma, a personal history of atopic dermatitis, or both. METHODS: Participants enrolled in the Prevention of Early Asthma in Kids study (n = 285) on the basis of a modified Asthma Predictive Index were characterized on the basis of allergy and asthma questionnaire responses and allergy skin puncture test results. RESULTS: The majority of the children (60.7%, n = 148) were sensitized to either food or aeroallergens. Male children were significantly more likely to be sensitized to aeroallergens ( P = .03) and to have a blood eosinophil level of 4% or greater ( P = .03) and a total serum IgE level of greater than 100 IU/mL ( P = .0004). Additionally, eosinophilia and total serum IgE level had the strongest correlation with aeroallergen sensitization. CONCLUSION: The high prevalence of aeroallergen sensitization in this high-risk cohort suggests that aeroallergens might have an important role in the early development of asthma. As such, the Prevention of Early Asthma in Kids cohort appears to be an appropriate cohort in which to test whether early intervention with an inhaled corticosteroid can significantly attenuate, or perhaps even prevent, the allergic march from the initial stages of allergic sensitization to the subsequent development of asthma in toddlers with episodic wheezing.     

The allergy epidemic extends beyond the past few decades

BACKGROUND: Increased prevalence of allergic diseases in western societies has been described as an epidemic. The precise turning point for the epidemic and the antigens responsible for it remain obscure. OBJECTIVE: To evaluate how the prevalence of atopic disease has changed in terms of detectable sensitization to aeroallergens and dietary allergens in a cross-sectional comparison of subjects from birth cohorts more than 60 years apart. METHODS: We studied four groups of 100 subjects each (at ages 7, 27, 47 and 67 years), representing those born in 1990, 1963-66, 1943-46 and in 1923-26, respectively. Serum total and specific IgE concentrations against aeroallergens and dietary allergens were determined. A questionnaire elicited information on symptoms, allergic diseases and medication. RESULTS: The proportion of subjects with detectable IgE antibodies against aeroallergens increased consistently from the oldest to the youngest birth cohorts; chi2 trend=56.809, P<0.0001. Similar progression was not seen in sensitization to dietary allergens. The proportion of those with diagnosed asthma differed significantly (chi2=13.45, P=0.004) across the birth cohorts. The lowest prevalence of asthma and sensitization to dietary allergens was detected in those born in 1943-46, i.e. during or immediately after World War II. CONCLUSION: Prevalence of sensitization to airborne allergens, unlike that to dietary allergens, has increased over a long period of time. Our results support the concept of the immune function being programmed by external factors early in life. They also call for caution when interpretations of the pace and possible causes of the allergy epidemic are made on the basis of short-term studies.     

Allergic sensitization to common airborne allergens among adults in Estonia

BACKGROUND: Allergies and asthma exhibit a growing health problem in the world. Sparse data are available about the prevalence of allergic sensitization in Estonia and Eastern Europe as well. We studied the prevalence of allergic sensitization, the associations between respiratory symptoms and allergic sensitization, and the influence of age, gender, area of residence, number of siblings and other demographic attributes on allergic sensitization in the population aged 17-69 years. METHODS: We conducted a cross-sectional study with 1,346 randomly selected participants distributed in 3 geographically and culturally distinct areas of Estonia. Sensitization to 15 aeroallergens was assessed by skin prick tests. The study also included a structured interview. RESULTS: The total prevalence of allergic sensitization was 33.0%. When estimated in patients aged 20-44 years, the prevalence was 38.5%. The most common sensitizer was cockroach followed by storage mites, while sensitization to cat, dog or pollen (common sensitizers in Scandinavian countries) was low. Allergic sensitization was significantly more common in urban and suburban compared with rural areas. Storage mites were the most common sensitizers in rural areas. Living in urban or suburban areas before the age of 5 significantly increased the risk for positive skin prick tests to several allergens. CONCLUSIONS: A higher prevalence of allergic sensitization than previously believed was found. Cockroach and storage mite allergens are suggested to be included in the routine investigation panel in Estonia.     

Food allergen sensitization in inner-city children with asthma

BACKGROUND: Asthma continues to be an increasing cause of morbidity in the pediatric population, and studies have shown an association between food sensitivity and asthma. OBJECTIVE: We investigated the degree of food allergen sensitization in inner-city patients with asthma. METHODS: Five hundred four random serum samples from the National Cooperative Inner City Asthma Study were evaluated for specific IgE (UniCap) to 6 common food allergens (egg, milk, soy, peanut, wheat, and fish). Statistical analyses were performed to determine food sensitization prevalence and its association with asthma morbidity. RESULTS: Forty-five percent of patients had evidence of sensitization (food-specific IgE > or = 0.35 kU/L) to at least 1 food. Nineteen percent had IgE levels at > or = 50% positive predictive value for clinical reactivity to at least 1 food, with 4% of patients having levels > 95% positive predictive value for food allergy. Children sensitized to foods had higher rates of asthma hospitalization (P < .01) and required more steroid medications (P = .025). Sensitization to foods also correlated with sensitization to more indoor and outdoor aeroallergens (P < .001). CONCLUSION: Food allergen sensitization is highly prevalent in the inner-city population with asthma, and it is associated with increased asthma healthcare and medication use. Therefore, food allergen sensitivity may be a marker for increased asthma severity.     

Relationships between atopy and lung function: results from a sample of one hundred medical students in Japan.

BACKGROUND: The prevalence of allergic diseases has been increasing dramatically and several studies have shown that atopy is related to asthmatic symptoms and bronchial hyperresponsiveness. OBJECTIVE: To observe the relationships between atopic status and asthmatic predisposition (obstructive change in lung function) in apparently healthy young adults in Japan. METHODS: A sample of 100 healthy Japanese medical students were subjected to a skin prick test for 11 common aeroallergens and food allergens, and their spirometric lung function was measured. RESULTS: Surprisingly, 90% of them showed a positive prick test result for at least one of the 11 allergens tested, and 59% of them showed allergic responses to more than three allergens. The positive rate for Dermatophagoidesfarinae (Der) was the highest (71.0%), followed by house dust (57.0%), Dactylois gloinerata (42.0%), Cryptomeria gromerata (Cry) (40.0%), and cat fur (39.0%). Furthermore, there was no statistical difference in the positive rates for Der and Cry between groups with and without either the present illness or past history of any of the three major allergic diseases: bronchial asthma (BA), atopic dermatitis (AD), or allergic rhinitis (AR). Compared with the positive rates for these aeroallergens, those for food allergens were much lower (4% to 9%). Several lung function parameters, including the levels of FEV1% and %V50 which reflect obstructive pulmonary changes, showed significant negative correlation to the number of skin prick test-positive allergens. The same correlation was observed for groups without either the present illness or past history of BA. CONCLUSION: These data suggest that those who are multi-allergic tend to feature subclinical asthma-like changes in their lung functions. Further studies are needed to determine whether this multi-allergic status can lead to future onset of asthma or other allergic diseases.     

Bronchial challenges with aerosolized food in asthmatic,food-allergic children

BACKGROUND: Allergic asthma is usually considered to be provoked by aeroallergens. However, we have recently recognized a group of children with food allergies who also develop asthma when exposed to the aerosolized form of the food. METHODS: Between 1997 and 1999 we prospectively identified children with an immunoglobulin (Ig)E-mediated food allergy who develop asthma on inhalational exposure to the relevant food allergen while it is being cooked. Subjects were exposed for 20 min to the aerosolized form of the allergen and the symptoms and the lung function were monitored. Aerosolization was achieved by cooking the food in a small room. Where possible challenges were double-blinded. RESULTS: We identified 12 children with an IgE-mediated food allergy who developed asthma on inhalational exposure to food. The implicated foods were fish, chickpea, milk, egg or buckwheat. Nine out of the 12 children consented to undergo a bronchial food challenge. Five challenges were positive with objective clinical features of asthma. Additionally, two children developed late-phase symptoms with a decrease in lung function. Positive reactions were seen with fish, chickpea and buckwheat. There were no reactions to the seven placebo challenges. CONCLUSIONS: We have presented a prospective series of children with food allergy who developed symptoms of asthma with exposure to aerosolized food allergens. Our data demonstrates that, as in the case of other aeroallergens, inhaled food allergens can produce both early- and late-phase asthmatic responses. This highlights the importance of considering foods as aeroallergens in children with coexistent food allergy and allergic asthma. For these children, dietary avoidance alone may not be sufficient and further environmental measures may be required to limit exposure to aerosolized food.     

Dichotomy of food and inhalant allergen sensitization in eosinophilic esophagitis

BACKGROUND: Eosinophilic esophagitis (EE) is an emerging condition where patients commonly present with symptoms of gastroesophageal reflux disease and fail to respond adequately to anti-reflux therapy. Food allergy is currently recognized as the main immunological cause of EE; recent evidence suggests an etiological role for inhalant allergens. The presence of EE appears to be associated with other atopic illnesses. OBJECTIVES: To report the sensitization profile of both food and inhalant allergens in our EE patient cohort in relation to age, and to profile the prevalence of other allergic conditions in patients with EE. METHOD: The study prospectively analyzed allergen sensitization profiles using skin prick tests to common food allergens and inhalant allergens in 45 children with EE. Patch testing to common food allergens was performed on 33 patients in the same cohort. Comorbidity of atopic eczema, asthma, allergic rhinitis and anaphylaxis were obtained from patient history. RESULTS: Younger patients with EE showed more IgE and patch sensitization to foods while older patients showed greater IgE sensitization to inhalant allergens. The prevalence of atopic eczema, allergic rhinitis and asthma was significantly increased in our EE cohort compared with the general Australian population. A total of 24% of our cohort of patients with EE had a history of anaphylaxis. CONCLUSION: In children with EE, the sensitization to inhalant allergens increases with age, particularly after 4 years. Also, specific enquiry about severe food reactions in patients presenting with EE is strongly recommended as it appears this patient group has a high incidence of anaphylaxis.     

Correlation between age and allergens in pediatric atopic dermatitis.

BACKGROUND: There has been significant progress recently in the clinical investigation of atopic dermatitis (AD), especially in the recognition of aeroallergens as aggravating factors in AD. However, sensitization to food allergens and aeroallergens in children with AD has not been fully studied. OBJECTIVE: To evaluate the correlation between age and allergens in children with AD. METHODS: A retrospective cross-sectional study was performed between January 1, 1999, and December 31, 2002, on 262 children with a definitive diagnosis of AD aged 0 to 16 years. Comparison of 3 age groups (<2 years, 2-5 years, and >5 years) with the correlation of food allergens and aeroallergens using the CAP-FEIA test was made using linear regression and logistic regression analyses. RESULTS: In children younger than 2 years, AD was associated with food allergens. In children aged 2 to 5 years, both food allergens and aeroallergens played an important role. In children older than 5 years, only elevated aeroallergen specific IgE levels were noted (P < .02). Age correlated negatively with food allergens and positively with aeroallergens after adjusting for sex (P < .04). Sensitization to aeroallergens may correlate with acquisition of the respiratory symptoms of the atopic state. CONCLUSIONS: Food allergens may be the major trigger of AD in early life, after which the role of environmental aeroallergens become more important and may be associated with respiratory sensitization.     

Prevalence of respiratory and atopic disorders in Chinese schoolchildren

BACKGROUND: Epidemiological surveys have shown that the prevalence of asthma in the Asian population is relatively low. Within the Chinese population, schoolchildren from Hong Kong were found to have the highest rate of asthma. OBJECTIVE: To compare the prevalence of respiratory and atopic disorders, and to assess the role of atopy in the development of asthma, in Chinese schoolchildren from Hong Kong, Beijing and Guangzhou. METHODS: Community-based random samples of schoolchildren aged 9-11 years from three Chinese cities (Hong Kong, Beijing and Guangzhou) were recruited for study using the International Study of Asthma and Allergies in Childhood (ISAAC) Phase II protocol. Subjects were studied by parental questionnaires (n = 10902), skin-prick tests (n = 3479) and skin examination (n = 3479). RESULTS: The prevalence rates of current wheeze, speech limiting wheeze, rhinoconjunctivitis and flexural dermatitis were significantly more common in Hong Kong than in Beijing or Guangzhou. The atopy rate was also higher in Hong Kong (41.2%) than in Beijing (23.9%) or Guangzhou (30.8%). Atopy was strongly correlated with current wheeze (OR 7.74; 95% CI = 5.70-10.51). Subgroup analyses of children from Hong Kong revealed that children born in mainland China who had subsequently migrated to Hong Kong had a significantly lower rate of allergic symptoms and atopy than those children born in Hong Kong. CONCLUSION: Using a standardized written questionnaire along with a skin prick test and skin examination, we confirmed that the prevalence of asthma, allergic diseases and atopy was highest in schoolchildren from Hong Kong. Atopic sensitization is an important factor associated with asthma in Chinese children.     

Cytomegalovirus infection and development of allergic diseases in early childhood: interaction with EBV infection?

BACKGROUND: Chronic replication of cytomegalovirus and EBV in early life may affect the immune system and play a role in the development of allergy in children. OBJECTIVE: To assess the relation between cytomegalovirus infection and allergic disorders in children, including a possible interaction with EBV infection. METHODS: From a prospective birth cohort study in Stockholm, on factors of importance for development of allergy, 2581 four-year-old children were enrolled. The classification of allergic diseases was based on questionnaire answers and determination of IgE antibodies to common airborne and food allergens. IgG to cytomegalovirus was determined by a commercial ELISA and to EBV by indirect immunofluorescence. RESULTS: A total of 1191 (46%) children were cytomegalovirus-seropositive. There were no significant associations between seropositivity to cytomegalovirus and allergic manifestations, such as bronchial asthma, suspected allergic rhinitis, or atopic dermatitis. Seropositivity to cytomegalovirus alone, ie, without seropositivity to EBV, was related to IgE antibodies to airborne and food allergens (adjusted odds ratio, 1.8; 95% CI, 1.2-2.9). An antagonism between cytomegalovirus and EBV in relation to sensitization to airborne and food allergens was suggested ( P = .05). CONCLUSION: The study does not support the hypothesis that previous cytomegalovirus infection plays an important role in the pathogenesis of bronchial asthma, suspected allergic rhinitis, or atopic dermatitis in children. However, in the absence of EBV infection, cytomegalovirus infection may be related to sensitization to airborne and food allergens.     

Prevalence and risk factors for allergic rhinitis and atopic eczema among schoolchildren in Israel: results from a national study.

BACKGROUND: There is growing evidence that the prevalence rates of asthma and allergic diseases are increasing, especially among children. Several risk factors are under investigation. OBJECTIVE: To evaluate the prevalence and risk factors for allergic diseases, including allergic rhinitis (AR) and atopic eczema (AE), among 13- to 14-year-old schoolchildren in Israel. METHODS: A modified version of the International Study of Asthma and Allergies in Childhood written questionnaire was administered to a national sample of schoolchildren 13 to 14 years old in Israel. The questionnaire was completed by the schoolchildren themselves. RESULTS: There were 10,057 complete questionnaires available for analysis. The prevalence of AR symptoms ever and current AR were 41.6% and 9.4%, respectively. Allergic rhinoconjunctivitis symptoms ever were reported by 15.8% of the children. The prevalence rates of 6 months of itchy rash ever and AE were 5.9% and 7.8%, respectively. After adjustment for demographic and environmental factors, current asthma, parental history of asthma, and population group were the most significant risk factors for current AR (odds ratio [OR], 4.47; 95% confidence interval [CI], 3.70-5.40; OR, 1.30; 95% CI, 1.02-1.66; and OR, 1.75; 95% CI 1.45-2.13; respectively) and AE (OR, 2.30; 95% CI, 1.80-2.90; OR, 1.80; 95% CI, 1.40-2.30; and OR, 1.70; 95% CI, 1.40-2.00; respectively). CONCLUSIONS: Israeli children have a low prevalence rate of current AR and a midrange rate of AE. Arabs have lower prevalence rates of allergic diseases than Jews, and the prominent risk factors for those diseases are current asthma and parental history of asthma.     

Relationship between aeroallergen and food allergen sensitization in childhood

BACKGROUND: Previous studies measuring the prevalence of allergen sensitization have been relatively small and used small numbers of allergens. To effectively evaluate children with atopic disease, we need an accurate knowledge of which allergens are important. OBJECTIVE: To measure the prevalence of sensitization within a large unselected birth cohort, to examine the associations between sensitization to different allergens and determine whether atopy can be defined by a small panel of allergens. METHODS: The Avon Longitudinal Study of Parents and Children is a population-based birth cohort of 13,638 singletons surviving to 4 weeks of age. The cohort was skin tested at 7 years of age to house dust mite (Dermatophagoides pteronyssinus), grass pollens, cat, peanuts, mixed tree nuts and egg and one of three other panels: animal danders, foods or aeroallergens. Sensitization was defined as a weal diameter of > or =3 mm. The strength of associations between sensitization to different allergens was tested by calculating the odds ratio adjusted for sensitization to D. pteronyssinus and grass pollen and gender. RESULTS: Valid data were obtained from 6412 singletons. Sensitization was most common to aeroallergens: grass pollens (8.5%), D. pteronyssinus (7.8%), cat (4.9%), D. farinae (3.6%), dog (2.7%), horse (1.4%), rabbit (1.4%). Of the foods tested, the most common sensitization was to peanut (1.4%) and mixed tree nuts (1.0%). More than 95% of subjects with sensitization to any of the 29 allergens tested were sensitized to one of grass, D. pteronyssinus or cat allergen. There were strong associations of multiple sensitizations both within and between different allergen classes (pollens, animals, foods, peanut and tree nuts). CONCLUSIONS: Seven-year-old children in the UK are primarily sensitized to aeroallergens, but also to peanuts and tree nuts. There are strong associations between sensitization within allergen groups as well as between allergen groups. Further studies are required to observe whether similar associations are seen with clinical allergy to these allergens.     

Comparative prevalence of sensitization to common animal, plant and mould allergens in subjects with asthma, or atopic dermatitis and/or allergic rhinitis living in a tropical environment

BACKGROUND AND OBJECTIVES: Current information suggests that the expression of allergic diseases is determined by the exposure and nature of the allergen. The objectives of the present study were to determine if the nature of allergenic exposition to animal, plant or fungal allergens influenced the clinical manifestations of atopic dermatitis (AD), allergic rhinitis (AR) or asthma (AS) in patients living in a tropical environment. The prevalence and degree of sensitization to these allergens were analysed by age and gender. SUBJECTS AND METHODS: A total of 1496 atopic cases, grouped according to the primary diagnosis of AD or AR or AS, were skin tested using a standardized allergen panel. Participants were categorized by age groups. The atopic index (AI) and mean weal diameter (MWD) as well as the prevalence of positive skin tests were determined for each of the patient groups and compared by age groups. RESULTS: The prevalence of atopy as well as the AI and the MWD peaked at 6-15 years of age and declined thereafter. In all the patients tested, the prevalence of sensitization was, in decreasing order; dust mites 94.3%, cockroach 41.5%, pets 31.5%, plant allergens 31.1% and fungal 19.4%. Eight hundred and ninety-three atopic patients were exclusively sensitized only to animal allergens. Of these, 38.4% had AD, 31.3% had AR and 30.5% with AS. CONCLUSION: These data demonstrate that for patients with AD, AR and AS living in a tropical environment, the prevalence of positive skin reactions to animal allergens is highest followed by plant and fungal allergens. We did not observe any association between the type of allergen and clinical manifestations. The index of atopy was similar for both sexes. The prevalence and degree of sensitization were shown to peak in young adults independent of the allergen in AD and AR patients.