Eczema does not occur in the absence of T cells. Here we provide an overview on the regulatory impact which T cells have on the establishment and maintenance of atopic dermatitis. Particularly, we outline the role of different T-helper cell subsets (i.e. Th-1, Th-2, T-regulatory and Th-17 cells) and their distinct influence on the cutaneous inflammatory reaction at different stages of the disease. Eczema is characterized by epidermal inflammation and thus T-cell/ker - atinocyte interactions are of particular relevance in this condition. Alterations in innate and adaptive immunity involving T cells result in susceptibility to skin infections and in hyperreactivity reactions to environmental stimuli which in turn determine the course and severity of atopic dermatitis.