The development of atopic phenotypes: genetic and environmental determinants.

Atopic manifestations may be present from infancy to adolescence. Atopic dermatitis represents the first clinical manifestation followed by allergic symptoms of the upper or lower airways. IgE responses to alimentary or environmental allergens are hallmarks of atopy in childhood. Characteristically infantile IgE responses to cow's milk and hen's egg are the first immunological markers of atopy. In many cases they are followed by IgE responses to indoor or outdoor allergens, which suggests a high risk for the development of persistent asthma in childhood. During recent years a variety of genes for both asthma and atopic dermatitis have been described. Infantile diet, early exposure to environmental allergens and a variety of environmental and lifestyle factors may act as strong modulators of atopy during the first decade of life.