Contact hypersensitivity: Animal tests

After reviewing general aspects and the historical development of predictive animal skin sensitization tests, the recommended tests of the OECD and EC are discussed. Background information is given on the changes that have occurred during the last 2 yr. Although many factors are known to influence induction and elicitation of contact allergy in animals, the discussion is focused on the choice of induction concentration and the vehicle. Differences in general screening strategies between Europe and the USA are considered. The paper concludes with a discussion about the importance of in-house validation of the methods used for proper prediction of the sensitizing potential of chemicals and with remarks on predictive in vitro tests.