Atopic eczema and food allergy.

Approximately one-third of children with severe atopic eczema suffer from a food allergy, whereas in adult patients, food allergies are rare. In child patients, three different clinical reaction patterns can be differentiated as follows: (1) immediate-type reactions, (2) isolated late eczematous reactions, and (3) combined immediate-type and late eczematous reactions. In childhood food allergies, food allergens, such as cow's milk or hen's egg, are primarily responsible for allergic reactions, while in adolescents and adults, food allergies often develop consecutively after primary sensitization to pollen allergens. Dysfunctions in the epidermal barrier seem to be vitally important in the development of food allergies in patients with atopic eczema by facilitating sensitization after epicutaneous allergen exposure. Further investigation is required to determine the role of intestinal epithelial barrier defects in the pathogenesis of these allergies as well as the genetic characteristics associated with an increased risk of food allergy. The diagnosis of eczematous reactions to food requires a careful diagnostic procedure, taking into account a patient's history and sensitization patterns. The clinical relevance of sensitization often has to be proven by an oral food challenge, with the rating of the skin condition by validated scores after 24 h and the later evaluation of the eczematous reaction.