Prevalence and clinical features of adverse food reactions in Portuguese children
Jorge et al.
Allergy Asthma Clin Immunol
Prevalence and clinical features of adverse food reactions in Portuguese children
Arminda Jorge 0 2 3
Elisa Soares 0 3
Emanuel Sarinho 1
Felix Lorente 6
Jorge Gama 5
Luís Taborda‑Barata 0 3 4
0 CICS‐Health Sciences Research Centre, University of Beira Interior, Avenida Infante D. Henrique , Covilhã 6200‐506 , Portugal
1 UFPE Allergy & Clinical Immunology Research Centre, Pernambuco Federal University , Recife , Brazil
2 Department of Paedi‐ atrics, Cova da Beira Hospital , Covilhã , Portugal
3 CICS‐Health Sciences Research Centre, University of Beira Interior, Avenida Infante D. Henrique , Covilhã 6200‐506 , Portugal
4 Department of Allergy & Clinical Immunology, Cova da Beira Hospital , Covilhã , Portugal
5 Department of Mathematics, Faculty of Sciences, University of Beira Interior , Covilhã , Portugal
6 Department of Paediatrics, Salamanca University Hospital , Salamanca , Spain
Background: The prevalence of adverse food reactions (AFR) has been increasing in the western world. Clinical manifestations are diversified and it may not be possible to clinically discriminate between IgE and non‑ IgE mediated AFR. In Portugal, the prevalence of AFR and food allergies in children is not known. Thus, the objectives of this study were to determine the prevalence of AFR in central Portugal. Methods: Point prevalence study in 3-11 year‑ old schoolchildren from Central Portugal. Food‑ related questionnaires, skin prick tests (SPT) with foods and determination of food‑ specific IgE levels were performed. Results: Of 4045 schoolchildren, 2474 (61.2%) accepted to be included in the study. Global prevalence of AFR was 7.1% (95% CI 6.2-8.1), based upon the initial questionnaire, 4.6% (95% CI 3.9-5.5), based upon a confirmatory questionnaire and the prevalence of probable food allergy (IgE‑ associated AFR: positive history + positive SPT and/or positive specific IgE) was 1.4% (95% CI 0.9-1.9). Most frequently implicated foods were fresh fruits, fish and egg. A first episode at an earlier age, mucocutaneous and anaphylactic reactions were more frequent in IgE‑ associated AFR. Conclusions: The prevalence of probable food allergy in 3-11 year old Portuguese children from central Portugal is low and parents over‑ report its frequency. Most frequently implicated foods were fresh fruit and fish. Immediate type, polysymptomatic, and more severe reactions may commence at an earlier age and be more frequent in IgE‑ associated than in non‑ IgE associated reactions.
Adverse food reaction; Children; Food allergy; Prevalence
Background
The prevalence of adverse reactions to foods (AFR) has
been increasing, particularly in the first years of life
[
1–3
]. According to a recent metanalysis, the
prevalence of self-reported food allergies varies between 3
and 35%, depending upon the age group, the
geographical area and the methodology used [
4
]. This broad range
of values may have to do with different methodological
approaches which were used in the various studies;
furthermore, in some of the reports the sample of involved
only children followed up in specialty clinics whereas
in other studies the values were obtained in the
general population of children; finally, in some cases, these
self-reported values were backed up by oral provocation
studies whereas in other reports, only
questionnairebased results were used. Nevertheless, there is a
scarcity of studies carried out in the general population of
children.
The diagnosis of food allergies in children cannot
be made exclusively on the basis of reported
symptoms since although parents believe that their children
are allergic to foods, confirmation only takes place in
10–50% of the reported cases [
5, 6
]. For instance, a
review of five studies of food allergies in unselected
pediatric populations under 10 years of age concluded
that the prevalence of these allergies was higher when it
was based upon self-reports than when it was supported
by additional tests, which suggests that confirmatory
allergy tests must be performed [2].
Most frequently reported foods in association with
allergies in children are cow’s milk, egg, peanut and
wheat, and clinical manifestations range from
localized cutaneous reactions to life-threatening
anaphylaxis [
6–8
]. The most efficient therapeutic option for
food allergies is food eviction [
6, 8
]. It is, therefore,
important to distinguish between situations of true
IgE-associated food allergies and other situations that
may involve intolerance to food, other forms of
nonIgE-mediated food allergy and even common
paediatric gastroenterological situations and this is where
allergy tests and, when necessary, food challenges are
required [9]. Independently of oral provocation tests
remaining the “gold standard”, skin prick tests (SPT)
and determination of levels of specific IgE should be
performed if the clinical history strongly suggests food
allergy and there is a clear suspicion of the implica (...truncated)