Low-Applied-Dose Extrapolation of Induction and Elicitation of Contact Allergy in the Evaluation and Management of Sensitization Risk from Kathon CG Isothiazolone in Products

Proper management of any risk first requires a reasonable assessment of the potential danger. The limited power of experimental studies with a small number of subjects (10 to 300) can be aided by the use of low-applied-dose extrapolation to render predictions of relatively low-incidence adverse health effects in large populations (10,000 to 800,000,000) of people. This work discusses these issues and outlines an approach for extrapolation using data from animal or human testing. A scheme is presented in which, without enough human data to establish a direct dose-response function, information from guinea pig tests can be used to devise a working model to estimate human dose-response. Induction and elicitation of contact allergy are modeled and treated as separate entities in the evaluation of their risks to human health. The incidence of elicitation is presented as the critical element because it describes the chances of active skin reaction or disease.