In vitro and in vivo testing techniques for allergic contact dermatitis.

A variety of preclinical and clinical models have been developed for assessing the skin sensitization potential of chemicals. These models have been invaluable in identifying potential allergens and providing the information needed to conduct sound skin sensitization risk assessments. Of course, all models have inherent strengths and limitations. In the area of skin sensitization, significant advances have been made in understanding the underlying mechanisms of allergic contact dermatitis. This knowledge has been critical in the development of new in vitro and in vivo approaches for assessing the skin sensitization potential of chemicals. This article presents basic immunologic information that is being used to aid in the identification of cellular markers for differentiating irritant and allergic reactions in animals and humans. In addition, data are reviewed on the evaluation of skin equivalent cultures for the identification of skin allergens in vitro.