Food allergy: manifestations, diagnosis and management

Similar prevalence, different spectrum: IgE-mediated food allergy among Turkish adolescents

BACKGROUND

Scarcity of reliable data on food allergy prevalence exists in Turkey. We aimed to assess reported and confirmed IgE-mediated food allergy prevalence, and define the spectrum of allergenic food.

METHODS

We prospectively evaluated the ISAAC Phase II study population for food allergy. Participants that reported experiencing food allergy symptom in the last year and/or were skin prick test positive for a predefined list of food allergens, were interviewed via telephone, and those considered as having food allergy were invited to undergo clinical investigation, including challenge tests.

RESULTS

A total of 6963 questionnaires were available. Parental reported food allergy prevalence and skin prick sensitisation rate were 20.2 ± 0.9% and 5.9 ± 0.6%. According to the above-defined criteria, 1162 children (symptom positive n=909, skin prick test positive n=301, both positive n=48) were selected and 813 (70.0%) were interviewed via telephone. Out of 152 adolescents reporting a current complaint, 87 accepted clinical investigation. There were 12 food allergies diagnosed in nine adolescents, with food allergy prevalence of 0.16 ± 0.11%. The most common foods involved in allergic reactions were walnut (n=3) and beef meat (n=2), followed by hen's egg (n=1), peanut (n=1), spinach (n=1), kiwi (n=1), cheese (n=1), hazelnut (n=1) and peach (n=1).

CONCLUSIONS

While parental reported food allergy prevalence was within the range reported previously, confirmed IgE-mediated food allergy prevalence among adolescents was at least 0.16%, and the spectrum of foods involved in allergy differed from Western countries, implying environmental factors may play a role.

Pediatric food allergy update

Food allergy is mostly a childhood disease that differs from the adult-onset allergy in several aspects, including the prevalence, commonly offending foods, symptomatology, and prognosis. The prevalence is much overestimated by the public, but it probably affects up to 6% of children. In some cases, the diagnosis might be clearly evident, but in most cases an expert evaluation may be needed that usually includes verification by challenge testing. Currently, the management of food allergy is avoidance of the offending foods together with the availability of pharmacologic agents for symptomatic treatment, including self-administered epinephrine. The latter is of utmost importance in highly allergic subjects because accidental trivial exposure is not uncommon. Recent studies promise immunomodulatory agents that might be of potential use for prophylaxis. One such agent is anti-immunoglobulin E, which might be available in the near future.