[Epidemiology of food allergies]

Difficulties resulting from diagnosis of food allergies show an impact on the validity of epidemiological data, which are mainly based on questionnaire data or results from allergy tests for evidence of specific IgE antibodies. The frequency of self-reported adverse food reactions in population based studies ranges between 5% and 33% with women reporting a higher frequency of such reactions. Only two epidemiological studies have performed double blind, placebo-controlled oral food challenge tests. Extrapolating these results, the prevalence of food allergies is estimated at 2% within the general population. An epidemiological questionnaire-based study in France reports on 3.5% of the general population suffering from food allergies. According to studies of the Allergy Ward in Zürich, in 46-60% of all cases skin and mucosa are predominantly affected, with oral allergy syndrome and urticaria being the most frequent manifestations. A food allergy is significantly associated with different manifestations of atopy and predominantly to hay fever, atopic eczema, urticaria and asthma.