**1. Introduction**

Contact dermatitis is an inflammatory disease of the skin resulting from direct contact with foreign substances. Understanding the immunological processes that cause the disease is therefore essential for the development of new therapeutic strategies.

Murine models of chemically induced dermatitis have played an essential role in our understanding of the pathophysiology of contact dermatitis, unraveling the role played by inflammatory mediators and identifying potential targets for therapeutic interventions.

In the present chapter we review data obtained in animal models of allergic and irritant contact dermatitis and provide basic protocols to reliably induce contact dermatitis.

A major intent of this chapter is to highlight the respective role of innate and adaptive immune cells in contact dermatitis pathogenesis as revealed by murine studies. Through genetic ablation of single molecules or depletion of specific cell subsets, murine studies provide novel insight on the role of different components of the immune system in the development of contact dermatitis. We review the experimental evidence revealing the role of different T cell subsets in contact dermatitis development, focusing our attention on mechanisms responsible for maintenance or disruption of immune-tolerance. Our analyses will focus on molecular pathways which are promising candidates as targets of future biological therapies.
