Abstract

Abstract:The belief that Negro skin resists irritants better than Caucasian skin was tested by quantitative patch test exposure to dinitrochlorobenzene (DNCB) in acetone. With concentration as the variable, the minimal perceptible erythema (MPE) dose of DNCB was determined on the backs of Caucasians and light and dark Negroes, on both normal skin and skin from which stratum corneum had been stripped. Caucasian MPE levels were significantly lower than those of either dark Negroes or the combined Negro groups. Removal of stratum corneum before exposure to the irritant rendered these groups not significantly different in MPE levels. These findings suggest that Negro stratum corneum is a more effective barrier to irritants. What accounts for this superiority is not known.