New aspects of food allergy in patients with atopic dermatitis

Food allergy is a common problem in patients with atopic dermatitis, particularly in children. Cow's milk, hen's egg, soy and wheat have been identified as frequent food allergens in this age group. While immediate reactions to food are well characterized, the importance of food as a provocation factor for late eczematous reactions has been a subject of debate for several decades. We have investigated the importance of food for the induction of late eczematous reactions in children with atopic dermatitis aged 1 - 10 years. This article shows the results of our study and discusses the previous literature. 46% of our challenges were related to a clinical reaction. 43% of these reactions were associated with an isolated immediate reaction. An exacerbation of atopic dermatitis (late eczematous reaction) commonly occured 24 hours after the ingestion of food. Isolated late eczematous reactions were seen in 12% of all positive challenges. 45% of the positive challenges were associated with late eczematous responses, which followed immediate-type reactions. We correlated the clinical outcome to the results of specific IgE determinations and atopy patch tests, which resulted in poor predictive values for both in-vitro and skin tests particularly for the late eczematous reactions. Therefore, food challenges have still to be regarded as the gold standard for the appropriate diagnosis of food responsive eczema in children with atopic dermatitis.