Patch test sensitivity to Kathon CG

Among 1511 consecutive patients patch tested with Kathon CG at 100 ppm active ingredient, 13 (0.8%) gave a positive reaction. Use test with a lotion containing Kathon CG (8.6 ppm) revealed no reaction in 11 patients with a positive patch test. It is concluded that a positive patch test reaction to 100 ppm does not initiate eczema after use of products preserved with Kathon CG in the low concentrations (3-15 ppm) used in final products.