Anaphylaxis to foods in a population of adolescents: incidence, characteristics and associated risks.

BACKGROUND: Information about severe reactions to foods in adolescence is limited. OBJECTIVE: To describe reactions to foods, including anaphylaxis, with regard to incidence, characteristics and associated risks, among 16-year-olds (adolescents) in a large, population-based birth cohort. METHODS: Parent-reported questionnaire data from ages 2-3 months, and 1, 2 and 16 years were used (N = 3153). Anaphylaxis at age 16 years was defined per NIAID/FAAN criteria. Immunoglobulin E (IgE) antibodies to 14 common food and inhalant allergens were analysed at ages 4 (n = 2283) and 16 years (n = 2510). Among adolescents with food-related symptoms (FRS) and for whom blood was available (n = 221), 25 additional food allergen extracts or allergen components were analysed. Associations between reactions to foods, and sensitization and allergic multimorbidity were investigated. RESULTS: In the 12 months prior to the 16-year assessment, 8.5% of adolescents had FRS. This included 0.8% (n = 24) adolescents who were classified as having anaphylaxis, yielding an incidence rate of 761/100 000 person-years. One-third of adolescents accessed health care during anaphylaxis. Allergic multimorbidity in infancy, as well as sensitization to foods and airborne allergens at age 4 years, was associated with an increased risk for FRS in adolescence. Peanuts and tree nuts were the most common culprit foods for anaphylaxis, and fruits and vegetables for non-anaphylactic reactions. Adolescents with anaphylaxis were significantly more likely to be sensitized to storage proteins (Ara h 2, Cor a 9, Cor a 14) and to be polysensitized to foods (P < 0.001 vs. non-anaphylactic reactions). CONCLUSIONS AND CLINICAL RELEVANCE: The incidence of food-induced anaphylaxis during adolescence in our population-based birth cohort is higher than previously reported. Adolescents with anaphylaxis differ from adolescents with non-anaphylactic FRS with regard to culprit foods and sensitization. Adolescents with previous anaphylaxis are likely to be polysensitized to foods, particularly tree nut and peanut storage proteins, and which warrants consideration at follow-up.

Health-related quality of life in children with objectively diagnosed staple food allergy assessed with a disease-specific questionnaire.

AIM: Among Swedish children of 0-12 years old, we investigated various food allergy-related exposures associated with health-related quality of life using a food allergy-specific questionnaire among children allergic to the staple foods cow's milk, hen's egg and/or wheat, and contextualised worse food allergy-associated health-related quality of life using a generic questionnaire versus controls. METHODS: In total, 85 children with objectively diagnosed allergy to the staple foods were included as cases, and 94 children matched for age and sex were included as controls. We administered a food allergy-specific parent-completed questionnaire originally developed by EuroPrevall to cases only, and a generic health-related quality of life questionnaire (EuroQol Health Questionnaire, 5 Dimensions; EQ 5-D); to both cases and controls. RESULTS: Hen's egg was the most common offending staple food, affecting 76% of cases. Approximately 7% of cases were allergic to all three staple foods. Parent-reported respiratory and cardiovascular symptoms were associated with worse health-related quality of life. Elements of disease severity [previous anaphylaxis (p < 0.001); epinephrine autoinjector prescription (p < 0.003)] were negatively associated with health-related quality of life. Cases had worse health-related quality of life measured by the EQ-5D compared to controls (p < 0.01). CONCLUSION: The use of a disease-specific questionnaire revealed that disease severity in children with objectively diagnosed allergy to the staple foods cow's milk, hen's egg and/or wheat is associated with worse health-related quality of life. The use of a generic questionnaire confirmed that cases have worse health-related quality of life than controls.

Socioeconomic evaluation of well-characterized allergy to staple foods in adults.

BACKGROUND: The aim of the present study was to evaluate if total, direct, indirect, and intangible costs differ between a cohort of adults with well-characterized allergy to staple foods ('cases') and controls. METHODS: Swedish adults with objectively diagnosed food allergy to cow's milk, hen's egg, and/or wheat were recruited at an outpatient allergy clinic. Controls age- and sex-matched to cases were recruited from the same geographic area. For assessing the household costs of food allergy, a disease-specific socioeconomic questionnaire, developed within EuroPrevall, was utilized. RESULTS: Overall annual total costs at the household level were significantly higher among adults with food allergy compared with controls (the difference amounted to 8164 €), whereas direct costs did not differ between cases and controls. However, household healthcare costs and costs for medicines were significantly higher for cases vs controls. Furthermore, indirect costs were significantly higher for households with food-allergic adults vs households without food-allergic adults. Specifically, more time was spent on performing domestic tasks due to a family member's food-allergy-related illness, as well as shopping and preparing food, and seeking food-allergy-related information. Presence of food allergy also affected intangible costs. Adults with food allergy experienced overall lower health status compared with controls. CONCLUSIONS: Swedish adults with allergy to staple foods have higher total costs determined as direct, indirect, and intangible costs using the disease-specific socioeconomic questionnaire. Thus, total costs were 8164 € higher per year in households with at least one adult allergic to staple foods compared with controls.

Recurrent reactions to food among children at paediatric emergency departments: epidemiology of allergic disease.

BACKGROUND: Knowledge about repeated food reactions in paediatric emergency departments (ED) is sparse. OBJECTIVE: To investigate the incidence and potential risk factors for repeated ED visits for food-allergic reactions among children with a prior ED visit due to reactions to food. METHODS: A total of 358 children with ED visits at paediatric hospitals in Stockholm due to reactions to foods during 2007 (index-reaction) were investigated in relation to recurrent reactions until 30 June 2010. Adjusted Cox proportional hazard models were used to compute relative risks (RR) and 95% confidence intervals (CI). RESULTS: A total of 80 children had 116 ED revisits over a period of 873 patient-years, yielding an incidence rate of 9 per 100 patient-years. Known food allergy before the index ED visit in 2007 increased the risk for ED revisits (RR = 2.30, 95% CI 1.35-3.94). Likewise, prescription of adrenaline auto-injector before the index-reaction increased the risk (RR = 2.02, 95% CI 1.17-3.49). Twenty-one percent of the children had more severe reactions at the revisit, 38% less severe and 41% had reactions of comparable severity. However, among 44% of the children with comparable or less severe reaction at revisit, early treatment with adrenaline hampered the classification of change in severity. CONCLUSIONS AND CLINICAL RELEVANCE: Previously known food allergy and prior prescription of adrenaline are significant risk factors for ED revisits among children with a prior ED visit due to reactions to food. Our results indicate that the severity of the index-reaction cannot be used to predict the severity of the relapse.

Anaphylaxis and reactions to foods in children--a population-based case study of emergency department visits.

BACKGROUND: Information about acute reactions to foods among children is limited. OBJECTIVE: To describe the overall incidence of anaphylaxis in a paediatric emergency department (ED) setting and to describe reactions to foods in relation to sex and age, clinical characteristics and management. METHODS: In a review of medical records, children with ED visits at any of three paediatric hospitals in Stockholm County during 2007 were targeted. Inclusion criteria were any adverse reaction to foods or anaphylaxis. RESULTS: 383 children fulfilled the inclusion criteria of which 371 had had reactions to foods. The incidence of anaphylaxis was 32 per 100 000 person years irrespective of cause and food was involved in 92%. Tree nuts, particular cashew, and peanut were the most common eliciting foods, and in children under 3 years, reactions to these two food allergens were as common as reactions to milk and egg. Pollen-allergic children seemed to be admitted due to food-induced anaphylaxis more often during the deciduous tree pollen season compared with the rest of the year (P = 0.015). Symptoms from the lower airways occurred in 49% of children with anaphylaxis but without underlying asthma compared with 72% of children with anaphylaxis and asthma, P < 0.01. CONCLUSIONS AND CLINICAL RELEVANCE: Reactions to peanut and tree nuts are as common as reactions to milk and egg in early life. Concomitant exposure to airborne allergens seems to increase the risk of anaphylaxis to foods. Among children with anaphylaxis, wheeze is prevalent even in children without asthma diagnosis.

Development and comorbidity of eczema, asthma and rhinitis to age 12: data from the BAMSE birth cohort.

BACKGROUND: Allergy-related diseases are a public health issue, but knowledge on development and comorbidity among children is scarce. The aim was to study the development of eczema, asthma and rhinitis in relation to sex and parental allergy, in a population-based cohort, during childhood. METHODS: At 1, 2, 4, 8 and 12 years, parental questionnaires were used to obtain data on allergy-related diseases. Complete data for all five follow-up occasions were available from 2916 children. Odds ratios for the risk of any allergy-related disease in relation to heredity and sex were calculated using generalized estimating equations. RESULTS: At 12 years, 58% of the children had had eczema, asthma and/or rhinitis at some time. Disease turnover was high for all three diseases throughout the study. Comorbidity increased with age, and at 12 years, 7.5% of all the children were affected by at least two allergy-related diseases. Parental allergy was associated with increased comorbidity and more persistent disease and increased the risk of having any allergy-related disease (adjusted OR 1.76; 95% CI 1.57-1.97) up to 12 years. Male sex was associated with an increased risk throughout childhood. Boys and girls did not differ in disease persistence, and for comorbidity, the differences were minor. CONCLUSIONS: Allergy-related diseases may affect a majority of children. Eczema, asthma and rhinitis develop dynamically throughout childhood, and allergic comorbidity is common. These findings indicate that allergy-related diseases should be neither seen nor studied as isolated entities.

IgE to peanut allergen components: relation to peanut symptoms and pollen sensitization in 8-year-olds.

BACKGROUND: Allergen-specific IgE testing is often performed with crude peanut extract, but the results may be difficult to interpret because of cross-reactions between peanut and other plant allergens. The aim was to investigate IgE reactivity to peanut allergen components in children from a birch-rich region in relation to pollen sensitization and peanut symptoms. METHODS: From a birth cohort, clinical parameters were obtained through questionnaires and IgE antibody levels to peanut and birch pollen were measured. Different peanut/birch sensitization phenotypes were defined among 200 selected children. IgE reactivity to peanut and pollen allergen components was analysed using microarray technique. RESULTS: Peanut symptoms were reported in 87% of the children with IgE reactivity to any of the peanut allergens Ara h 1, 2 or 3 but not to Ara h 8 (n = 46) vs 17% of children with IgE reactivity to Ara h 8 but not to Ara h 1, 2 or 3 (n = 23), P < 0.001. Furthermore, symptoms were more severe in children with Ara h 1, 2 or 3 reactivity. Children with IgE reactivity both to Ara h 2 and to Ara h 1 or 3 more often reported peanut symptoms than children with IgE only to Ara h 2 (97%vs 70%, P = 0.016), particularly respiratory symptoms (50%vs 9%, P = 0.002). CONCLUSIONS: IgE analysis to peanut allergen components may be used to distinguish between peanut-sensitized individuals at risk of severe symptoms and those likely to have milder or no symptoms to peanut if sensitized to pollen allergens and their peanut homologue allergens.

Reported symptoms to peanut between 4 and 8 years among children sensitized to peanut and birch pollen - results from the BAMSE birth cohort.

BACKGROUND: Specific IgE tests are sometimes difficult to interpret due to structural similarities between certain food and pollen allergens. This may be the reason why concomitant sensitization to peanut and birch pollen is frequently seen. The aim of this study was to investigate reported symptoms to peanut- and birch pollen in relation to sensitization. METHODS: The data originate from 1928 children in the BAMSE birth cohort. Background factors and clinical parameters were obtained and the levels of IgE antibodies to peanut and birch pollen measured at 4 and 8 years. RESULTS: IgE antibodies to peanut were found in 5.5% and 7.4% of the children at 4 and 8 years, respectively. The IgE antibody levels to peanut were higher in children sensitized to peanut but not birch than in children sensitized to peanut and birch among both 4- and 8-year-olds (P = 0.093 and P = 0.003, respectively). Eight-year-olds sensitized to peanut but not birch, more often reported symptoms to peanut than children sensitized to both peanut and birch pollen (76%vs 46%, P = 0.002). The probability of reported symptoms to peanut increased significantly with increasing IgE levels to peanut, especially in 8-year-olds not sensitized to birch. CONCLUSIONS: Children sensitized to both peanut and birch pollen are less likely to report symptoms to peanut than children sensitized to peanut but not to birch pollen at 8 years. This is likely due to cross reactions between birch pollen and peanut and can explain the high sensitization rate to peanut in areas where birch trees are common.

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.

Sensitization to inhalant allergens between 4 and 8 years of age is a dynamic process: results from the BAMSE birth cohort.

BACKGROUND: There is limited knowledge of the development of IgE-antibody levels over time in childhood, with respect to persistency and co-sensitization to specific inhalant allergens. METHODS: Data from 2033 children participating in the BAMSE birth cohort was used. Background factors and clinical parameters were obtained and IgE antibody (ab) levels to eight common airborne allergens were measured (>or=0.35 kU(A)/L) when the children were 4 and 8 years of age. RESULTS: Between 4 and 8 years the proportion of children sensitized to any of the inhalant allergens tested increased from 15% to 25%. At 4 years IgE-ab to birch and cat dominated, whereas at the age of 8, there was a considerable increase in the proportion of sensitization to timothy and dog. Except for mites and moulds, IgE-ab levels to all aeroallergens increased significantly between 4 and 8 years among those already sensitized at 4. Transient sensitization to inhalant allergen was uncommon. Furthermore, sensitization to birch pollen at 4 years increased the risk for becoming sensitized to timothy, cat and dog later in life. Such an association was not observed among those sensitized primarily to animal dander. CONCLUSIONS: There is a prominent process of sensitization at pre-school age to inhalant allergens, and in Northern Europe sensitization to birch pollen early in life seems to be important for this process. Such a process has a probable impact on the development of allergic disease in the growing child.

Phenotypes of food hypersensitivity and development of allergic diseases during the first 8 years of life.

BACKGROUND: Longitudinal data from population-based studies on the development and persistence of food hypersensitivity (FHS) during childhood are almost absent. METHODS: A population-based birth cohort was established, and information on various exposures and symptoms of allergic disease were obtained from questionnaires when the children were 2 months, 1, 2, 4 and 8 years of age. Complete data were available on 3104 children. Children with reported FHS and doctor's diagnosis of food allergy (RDFA) were identified and allocated into transient, intermittent, late-onset and persistent phenotypes. Food allergen-specific IgE-antibodies (abs) to a mix of six common food allergens (fx5) were analysed at 4 and 8 years of age in 1857 children. RESULTS: The overall prevalence of reported FHS in combination with RDFA should be 3.1% at 1 year to 7.6% at 8 years of age. However, reactions to milk, egg, fish and wheat decreased, whereas an increase was seen for peanuts and tree nuts. Reported reactions to egg, peanuts or tree nuts early in life, as well as IgE-abs to food allergens at the age of 4, increased the risk of FHS at 8 years of age. Furthermore, FHS at young ages increased the risk for asthma, eczema and allergic rhinitis at 8 years of age, even when adjustments were made for children with these symptoms during the first 2 years of life. CONCLUSION: The increasing prevalence of FHS up to the age of 8 years probably reflects an increasing prevalence of allergy to birch pollen and pollen-related reactions to foods. Reactions to egg, peanuts and tree nuts early in life increase the risk of FHS at 8 years. Furthermore, reported FHS at young ages, even though transient, seems to increase the risk for other allergic diseases at 8 years of age.

The impact of food hypersensitivity reported in 9-year-old children by their parents on health-related quality of life.

BACKGROUND: There are only a few studies on the impact of food hypersensitivity (FHS) in children on health-related quality of life (HRQL). The present study was designed to examine this impact in a population-based birth cohort (BAMSE). METHODS: A nested case-control study was performed within the cohort. The parents of 1378 nine-year-old children filled out a generic questionnaire with 13 subscales (Child Health Questionnaire Parental Form 28 - CHQ-PF28) supplemented with disease-specific questions concerning FHS. There were 212 children with report of FHS. Another 221 children with allergic diseases but not FHS were examined for comparison. Furthermore, the impact of pronounced symptoms of FHS and of increasing levels of food-specific IgE antibodies on HRQL was also analysed. RESULTS: The children with FHS exhibited significantly lower scores on the subscales physical functioning, role/social limitations - physical and general health in the generic instrument. Furthermore, children with food-related symptoms from the lower airways were scored lower on Self Esteem, Parental Impact - time and Family Cohesion. Sensitization per se did not alter these patterns, but high levels of food-specific IgE-antibodies affected mental health and general health negatively. A physician's diagnosis of food allergy did not affect any of the subscales negatively. CONCLUSIONS: Parents reported that FHS exerts a negative impact on the HRQL of 9-year-old children, in particular in children with symptoms from the lower airways or if the FHS is associated with high levels of food-specific IgE-antibodies. Healthcare-givers must put major effort into improving and maintaining the HRQL of these children.

Patterns of quantitative food-specific IgE-antibodies and reported food hypersensitivity in 4-year-old children.

BACKGROUND: Diagnosis of food hypersensitivity (FHS) is difficult and interpretation of food allergy tests is complicated. OBJECTIVE: To investigate the probability of reported FHS in relation to levels of food-specific IgE-antibodies (AB) in a population-based setting of 4-year-old children (n = 2336). METHODS: Information on FHS was obtained from a questionnaire and specific IgE-AB to milk, egg, fish, peanut, soy and wheat were analysed. RESULTS: Thirty-one per cent of the children with reported FHS (n = 284) were sensitized (> or =0.35 kU(A)/l) to at least one of the tested foods compared with 11% of children without FHS (n = 2052). Furthermore, the probability of reported symptoms to milk, egg and fish increased with increasing levels of food-specific IgE-AB to the same food allergens. A similar trend was seen for peanut and wheat, but not for soy. Increasing levels of specific IgE-AB to milk or egg were also associated with an increasing risk of reported symptoms caused by other foods. CONCLUSIONS: Quantitative measurements of IgE-AB to milk, egg and fish are useful to evaluate IgE-associated FHS in preschool children also in a population based sample. Such measurements appear to be of limited value for soy bean and wheat, in particular as a screening method.