Chemical-associated allergy is the consequence of immune responses to the chemical, usually to chemicals bound to proteins. The immune responses are associated with some tissue damage resulting in adverse conditions, such as eczema (skin) or allergic asthma.
For the study of skin sensitizers well validated animal models are available; for respiratory sensitizers validated annual models are currently lacking. A lot of attention is given to non-animal tests to identify sensitizers, such as in silicon methods evaluating the chemical structure of the chemical in terms of potential sensitizing activity; in chemical approaches evaluation the potential of chemicals to bind to proteins, and in vitro cell systems. For the study of skin sensitizers integrated test procedures seem to work well, but for respiratory sensitizers much more research is needed to achieve that level.