Sequential Sensitization Tests in Animals and Humans for the Management of Dermal Risk Assessment

Abstract Animal and human test data used to assess delayed contact hypersensitivity potential before household products are sold, and the marketplace experience with these products, were reviewed. The premarket tests include initial animal screening by the modified Buehler method and clinical testing with human volunteers. The data show that the modified Buehler test is a useful, conservative method for screening product ingredients for sensitization potential before human exposure. However, the animal test used alone would exclude from use many materials that do not represent a practical human sensitization risk. The human repeat insult patch test (HRIPT) is a good predictor of sensitization potential. When coupled with product use testing in sensitive individuals, the HRIPT test provides the most reliable information for assessing dermal sensitization risks to consumers. This review covered a 5 year period and included a variety of household products that come in contact with the skin. The products are major brands sold throughout the United States and product types include those designed for laundry care, dish care, hard surface cleaning, personal cleansing, hair care, deodorant protection, and skin care. The consumers represent a broad population exposure base reflecting a diverse ethnic, demographic, and genetic predisposition for contact allergy. Marketplace problems were monitored by a toll-free telephone number on each product's label. Each consumer contact was provided an appropriate follow-up plan to address their concern. The absence of product-related sensitization problems in the marketplace supports the reliability of predictive testing for consumer products.