Current evidence of epidermal barrier dysfunction and thymic stromal lymphopoietin in the atopic march.

It has long been observed that the development of asthma, allergic rhinitis and food allergy are frequently preceded by atopic dermatitis, a phenomenon known as the "atopic march". Clinical, genetic and experimental studies have supported the fact that atopic dermatitis could be the initial step of the atopic march, leading to the subsequent development of other atopic diseases. This brief review will focus on the current evidence showing that epidermal barrier dysfunction and the keratinocyte-derived cytokine thymic stromal lymphopoietin play critical roles in the onset of the atopic march.