Sensitization Studies Skin and Mucous Membranes

Guinea-Pig Technique Although the guinea pig intracutaneous technique may not be entirely adequate (borderline cases of sensitization may be missed), 

Repeated chemical patch applications to both humans and animals reveal that certain chemicals at a given concentration do not produce primary irritation, but may elicit severe skin reactions after a number of exposures. Nevertheless, these reactions may not be considered incidents of sensitization, because after 10 to 14 days of rest, the skin recovers its original resistance to the chemical injury. Such chemicals are neither primary irritants nor sensitizers. 

For lack of a better term, such reactions have been called skinfatigue. This term is a misnomer in that it does not imply a condition in which the skin has lost 

Use Versus Patch Tests The use test is a method frequently employed to estimate the potential sensitizing ability of a product. Such a test is usually conducted by distributing the product to a large test panel, (e.g., the inhabitants of one or more large cities). Should the product be found acceptable to the general public, (e.g., tolerated without many serious complaints of injury), the manufacturer may feel justified in substituting this test procedure. The use test does not afford information on the product s acceptability and safety for use, and it is generally considered unsatisfactory since it lacks proper medical or other supervision of the test subject. Because of the lack of supervision, it is difficult to confer validity to the results, such as the extent of individual use, the nature, number, and seriousness of adverse reactions that the test chemical may produce. 

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