Measurement of diamine oxidase (DAO) during low-histamine or ordinary diet in patients with histamine intolerance.

BACKGROUND/OBJECTIVES: Quantification of diamine oxidase (DAO) concentrations in serum has been proposed as an adjunctive diagnostic modality for the evaluation of histamine intolerance (HIT). Limited empirical data exist concerning the influence of dietary patterns on DAO levels. SUBJECTS/METHODS: In the context of a prospective study employing a crossover design, 18 individuals diagnosed with HIT were randomized to initiate either a low histamine diet (LHD) or a conventional mixed diet (MXD). Serum DAO concentrations were measured at the commencement of the study and following each dietary phase. A control group underwent analogous DAO assessments without imposition of dietary constraints. RESULTS: During the time when a diet restricted in histamine was implemented, noticeable differences in changes in DAO levels did not become apparent when compared to the changes observed during the mixed (MXD) phase. Specifically, among the group, 10 of the 18 patients exhibited elevated DAO values subsequent to the LHD regimen, while the remaining eight displayed either reduced or unchanging DAO levels. The prevalence of elevated DAO levels in the LHD group did not differ significantly from that observed in the control group during the MXD phase. Additionally, during the LHD phase, patients reported a significant reduction in gastrointestinal and cutaneous symptoms. CONCLUSIONS: This prospective investigation underscores the enduring utility of a histamine-restricted diet, coupled with structured dietary reintroduction, as an efficacious diagnostic approach for individuals presenting with suspected food-related histamine hypersensitivity. Notably, the measurement of DAO levels appears to furnish only a limited capacity to discern dietary-induced fluctuations. Notwithstanding, the dynamics of DAO alteration do not appear to exhibit a discernible association with specific dietary patterns, a finding consistent across both patient and control groups.

Is DAO in serum affected by food challenge with a histamine-rich meal?

This case study examines the kinetics of the diamine oxidase levels after challenge with a histamine-rich meal in patients with histamine intolerance as an alternative diagnostic tool to conventional tests combined with the dietary intervention.

Impaired health-related quality of life in adolescents with allergy to staple foods.

BACKGROUND: Cow's milk, hen's egg and wheat are staple foods in a typical western diet. Despite the ubiquity of these foods, the impact of staple food allergy on health-related quality of life (HRQL) amongst adolescents is incompletely understood. The aims of this study were to make use of the Swedish version of EuroPrevall's disease-specific food allergy quality of life questionnaire-teenager form (FAQLQ-TF) and to investigate the association between objectively-diagnosed staple food allergy and HRQL amongst adolescents. METHODS: In this cross-sectional study, 58 adolescents aged 13-17 years [n = 40 (69 %) boys] with objectively-diagnosed allergy to the staple foods cow's milk, hen's egg and/or wheat and living in Stockholm, Sweden were included. Adolescents completed the FAQLQ-TF, which has a corresponding scale of 1 = best HRQL, and 7 = worst HRQL. Overall HRQL and domain-specific HRQL were established. Adolescents also reported symptoms, adrenaline auto injector (AAI) prescription and presence of other food allergies. A history of anaphylaxis was defined among those reporting difficulty breathing, inability to stand/collapse, and/or loss of consciousness. Clinically different HRQL was set at a mean difference of ≥0.5. RESULTS: Overall mean HRQL was poorer than average [mean: 4.70/7.00 (95 % CI 4.30-5.01)]. The domain risk of accidental exposure was significantly associated with clinically better HRQL than the domain allergen avoidance and dietary restrictions (mean difference = 0.76; p < 0.001). Girls had clinically worse, but not statistically significantly different mean HRQL than boys (mean difference = 0.71; p < 0.07). HRQL tended to be worse amongst those with allergies to more than three foods or an AAI prescription. The number and types of symptoms, including a history of anaphylaxis were not associated with worse HRQL. CONCLUSIONS: As ascertained via a food allergy-specific questionnaire, adolescents with staple food allergy report poorer than average HRQL, specifically in relation to emerging independence and the need for support. Girls have clinically worse HRQL than boys. The number and type of previous symptoms and history of anaphylaxis were not associated with worse HRQL.

Use of a basophil activation test as a complementary diagnostic tool in the diagnosis of severe peanut allergy in adults.

BACKGROUND: Diagnosis of severe peanut allergy is difficult and delays in making an accurate diagnosis may place the patient at risk. Adults with a history of anaphylaxis must strictly avoid any contact with peanuts or products that may contain traces of peanuts. For these persons, conventional evaluations with skin prick testing (SPT) and IgE tests may not be sufficient to assess the risk of anaphylaxis. Therefore, we investigated whether the basophil activation test (BAT) could be used for the diagnosis of severe peanut allergy in adults. We compared the non-invasive BAT with conventional laboratory diagnostic tests, including SPT and specific IgE to allergen extracts and components, for the diagnosis of severe peanut allergy. METHODS: Forty-seven persons with severe allergy to peanuts and a clinical diagnosis of anaphylaxis (PA-group), 22 subjects with peanut sensitization (PS-group) and 22 control (C-group) subjects, all in the age range of 18-60 years, were recruited retrospectively and prospectively into the study. Thirty-four patients with peanut allergy and 11 peanut-sensitized patients were sensitized to soy, while 36 patients in the PA-group and 20 patients in the PS-group were sensitized to birch pollen. All the patients and control subjects were investigated with BAT and SPT for responses to peanut, soy and birch extracts and their serum samples were assayed for the presence of specific IgE to peanut, soy and birch extracts, as well as IgE to allergen components (ISAC). RESULTS: In a multivariate factor analysis, severe peanut allergy (PA) was positively associated with SPT to peanut, IgE to peanut, BAT to peanut and IgE to rAra h 1, 2, 3 and 6 peanut components, as well as to soy components (nGly m 5 and nGly m 6). In contrast, peanut sensitization was positively associated with increased levels of IgE to rAra h 8, birch and birch-related components. BAT-detected reactivity to peanut was significantly higher in patients who had a history of severe allergy to peanuts, as compared with patients who were sensitized to peanuts (p < 0.001), and the receiver operating curve (ROC) analysis showed that BAT had high sensitivity and specificity for predicting severe peanut allergy, with a ROC area under the curve of 0.862. However, in the PA-group, the BAT results for peanut correlated only weakly with the levels of IgE to rAra h 1, 2 and 3 and nAra h 6. STUDY LIMITATIONS: oral provocation in the patients with a history of severe peanut allergy could not be performed to compare clinical reactivity with the BAT result due to ethical constraints. Neither was it possible to perform BAT with peanut recombinant allergens which were not available at the time the study commenced. CONCLUSIONS: BAT is useful in determining the severity of peanut allergy and may be used as a complementary diagnostic tool to ensure accurate diagnosis of severe peanut allergy in adults. Thus, it may reduce the need to subject these patients to further tests, including an open challenge with peanuts.

Household costs associated with objectively diagnosed allergy to staple foods in children and adolescents.

BACKGROUND: We previously reported that indirect and intangible costs burden households with a food allergic adult. We now extend our investigation to households with food allergic children and adolescents. OBJECTIVE: The objective of this study was to estimate direct, indirect, and intangible costs of food allergy in households with a child and/or adolescent with objectively diagnosed allergy to staple foods (cow's milk, hen's egg, and/or wheat), and to compare these costs with age- and sex-matched controls. METHODS: Direct and indirect cost parent-reported data collected via the Food Allergy Socio-Economic Questionnaire of 84 children (0-12 years) and 60 adolescents (13-17 years) with objectively diagnosed allergy to staple foods ("cases") and age- and sex-matched controls (n = 94 children; n = 56 adolescents) were compared. Annual household costs were calculated. Total household costs included direct plus indirect costs. Intangible costs included parent-reported health of their child and/or adolescent, standard of living, and perceptions of well-being. RESULTS: Amongst cases, total household costs were higher by €3961 for children and €4792 for adolescents versus controls (P < .05), and were driven by direct (eg, medications) and indirect (eg, time with health care professionals) costs. For children only, a history of anaphylaxis was associated with higher direct costs than no anaphylaxis (€13,016 vs €10,044, P < .05). Intangible costs (eg, parent-reported health of a child and/or adolescent) were significantly impacted amongst cases versus controls (P < .01). CONCLUSION: Households with a child and/or adolescent with objectively diagnosed allergy to staple foods have higher total household costs than controls. Direct and indirect costs were significantly higher for cases versus controls amongst children only. Amongst both age groups, such allergy adversely impacted intangible costs.

Intestinal allergic inflammation in birch pollen allergic patients in relation to pollen season, IgE sensitization profile and gastrointestinal symptoms.

BACKGROUND: Birch pollen allergic patients frequently experience gastrointestinal upset accompanied by a local allergic inflammation in the small intestine especially during the pollen season. However, it is not known if the GI pathology is connected to the subjective symptoms of the patient. The objective of this study was to evaluate the immune pathology of the duodenal mucosa and the serum IgE antibody profiles in birch pollen allergic patients in relation to their gastrointestinal symptoms, during and outside the birch pollen season. METHODS: Thirty-two patients with birch pollen allergy and sixteen healthy controls were enrolled in the study. Twenty allergic patients had gastrointestinal symptoms and twelve did not. All participants underwent an allergy investigation and gastroscopy with duodenal biopsy. The duodenal biopsies were retrieved during the pollen season (May-June) and off-season (November-March). The biopsies were immunostained for mast cells (IgE and tryptase), eosinophils, T cells (CD3), and dendritic cells (CD11c). Pollen-specific IgE antibodies were determined by ImmunoCAP and component microarray (ISAC). RESULTS: Patients in both pollen allergic groups showed similar degree of intestinal allergic inflammation during the pollen season regardless of gastrointestinal symptoms. The eosinophils, mast cells and dendritic cells were increased in the mucosa. Patients with gastrointestinal symptoms had significantly elevated IgE antibodies to birch (rBet v 1), hazelnut (rCor a 1), and apple (rMal d1) during the pollen season. CONCLUSIONS: Patients allergic to birch pollen have clear signs of an ongoing allergic inflammation in their intestinal mucosa, which is aggravated during the pollen season. The magnitude of the allergic intestinal inflammation is not associated with subjective gastrointestinal symptoms of the individual patient.

Health-related quality of life, assessed with a disease-specific questionnaire, in Swedish adults suffering from well-diagnosed food allergy to staple foods.

BACKGROUND: Our aim was to investigate the factors that affect health related quality of life (HRQL) in adult Swedish food allergic patients objectively diagnosed with allergy to at least one of the staple foods cow's milk, hen's egg or wheat. The number of foods involved, the type and severity of symptoms, as well as concomitant allergic disorders were assessed. METHODS: The disease-specific food allergy quality of life questionnaire (FAQLQ-AF), developed within EuroPrevall, was utilized. The questionnaire had four domains: Allergen Avoidance and Dietary Restrictions (AADR), Emotional Impact (EI), Risk of Accidental Exposure (RAE) and Food Allergy related Health (FAH). Comparisons were made with the outcome of the generic questionnaire EuroQol Health Questionnaire, 5 Dimensions (EQ-5D). The patients were recruited at an outpatient allergy clinic, based on a convincing history of food allergy supplemented by analysis of specific IgE to the foods in question. Seventy-nine patients participated (28 males, 51 females, mean-age 41 years). RESULTS: The domain with the most negative impact on HRQL was AADR, assessing the patients' experience of dietary restrictions. The domain with the least negative impact on HRQL was FAH, relating to health concerns due to the food allergy. One third of the patients had four concomitant allergic disorders, which had a negative impact on HRQL. Furthermore, asthma in combination with food allergy had a strong impact. Anaphylaxis, and particularly prescription of an epinephrine auto-injector, was associated with low HRQL. These effects were not seen using EQ-5D. Analyses of the symptoms revealed that oral allergy syndrome and cardiovascular symptoms had the greatest impact on HRQL. In contrast, no significant effect on HRQL was seen by the number of food allergies. CONCLUSIONS: The FAQLQ-AF is a valid instrument, and more accurate among patients with allergy to staple foods in comparison to the commonly used generic EQ-5D. It adds important information on HRQL in food allergic adults. We found that the restrictions imposed on the patients due to the diet had the largest negative impact on HRQL. Both severity of the food allergy and the presence of concomitant allergic disorders had a profound impact on HRQL.