Patch test sensitivity to the preservative Kathon CG in Spain

Kathon CG is a very well studied preservative used in cosmetics and toiletries. It is effective in low concentrations (3 to 15 ppm active ingredients) and exhibits outstanding antimicrobial activity against gram-negative and gram-positive bacteria, yeasts and fungi. Although this biocide is not considered to pose a toxicological hazard at recommended use levels, the sensitizing potential of Kathon CG has been established. From November 1988 to June 1989, we patch tested 626 unselected contact dermatitis patients with Kathon CG solution containing 200 ppm active ingredients and obtained 22 (3.5%) positive reactions. Relevance was established in 7 of the 22 patients. Women were predominantly sensitized, the principal source of sensitization being cosmetics.