Allergic reactions to foods are an important medical problem throughout the industrialized world. The occurrence of food allergy appears to be strongly influenced by genetics, but the basis of the genetic predisposition to food allergy has not been differentiated from that for atopy in general.
In addition, genetic susceptibility alone does not explain the prevalence of food allergy satisfactorily, leaving ample room to consider the importance of environmental influences (external, maternal, and gastrointestinal environment) and interactions between the host and the environment.
Several features of food allergy are highlighted in this review:
1) patients with severe food allergies are overwhelmingly atopic, but food allergy occurs only in approximately 10% of patients with other atopic diseases;
2) most patients are clinically reactive to a single food, and although a substantial minority have multiple food allergies, the variety of bonefide food allergies in a given individual is limited;
3) foods contain multiple proteins whereas only a small subset are allergenic;
4) there is likely an important contribution of the environment, becoming manifest in genetically susceptible individuals.
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