**1. Introduction**

Atopic eczema/dermatitis syndrome (AEDS) is a chronic inflammatory skin disease, very common in childhood (1). The prevalence of AEDS is estimated to 15–30% in children and 2–10% in adults while the incidence has shown a 2- to 3-fold increase in the past 3 decades in developed countries (2). This results in a significant socio-economic impact, that in the United States was estimated in a range from \$364 million to \$3.8 billion US dollars per year, usually considering only the direct but not the indirect costs (3). The disease is sustained by a complex interaction between genetic and environmental factors and is characterized by a skin barrier dysfunction resulting in epidermal damage and altered permeability to allergens and microbes (4). Depending on the association or not to IgE sensitization, AEDS may be defined as atopic or nonatopic. The two forms are clinically similar but show some differences regarding the histology, the kind of cells involved, and the cytokine pattern (5).
