Interspecies comparisons of skin irritancy

Abstract

In a series of patch testing experiments, 24 familiar household materials or industrial chemicals were applied to intact and abraded skin of rabbits, guinea pigs, and humans for four hours. Skin responses were graded 4, 24, and 48 hr after application of the patches. A number of materials caused greatly different reactions from one species to another. Some caused tissue damage at abraded sites in the animals, but caused only mild reactions on either intact or abraded sites of humans. Hypochlorite bleach caused severe reactions on intact human skin, but produced considerably less reaction on both intact and abraded skin of rabbits and guinea pigs. Sodium tripolyphosphate and sodium carbonate caused vesiculation at abraded sites of one of six humans, but produced only slight reactions on animal skin. From these results it is concluded (a) that neither rabbit nor guinea pig skin should be relied upon exclusively to identify potentially hazardous irritants to human skin and (b) that the testing of abraded skin is unnecessary and can be misleading in the interpretation of the results, making the animal tests less, rather than more, reliable. Although neither species is entirely reliable, even if abraded site testing is omitted, the rabbit and the guinea pig appear to be similarly predictive as models for preliminary screening of household products and their chemical components for skin irritancy.