Food allergy and atopic eczema.

As a contributing factor, certain foods can provoke skin lesions in some patients with atopic eczema. In newborns with an increased risk of atopy, exclusive breastfeeding during the first months of life and delayed introduction of solid food seem to inhibit or to retard the manifestation of atopic disease. The pathomechanism of provocation of eczema by food has not yet been elucidated. The frequent finding of specific immunoglobulin E (IgE) antibodies to the offending food items suggests that immediate type allergic reactions may be involved. Furthermore, other allergic or nonimmunologic (pseudo-allergic) mechanisms have to be considered. History taking, skin tests, and radioallergosorbent test (RAST) may provide some information with regard to eliciting food, but these procedures usually are not sufficient to obtain a conclusive diagnosis. Oral challenge tests have to be performed in a controlled manner in order to identify food items that are not tolerated and thus have to be avoided. As most of the patients react only to one or two food items and as these often differ from one patient to another, undirected exclusion diet regimens are unnecessary and unethical. Furthermore, such diets bear the risk of malnutrition and of anaphylactic reactions after reintroduction of allergenic food. Dietary recommendations in atopic eczema have to be based on a careful allergological workup of the individual patient.