Routine patch testing with the preservative system Kathon CG.

Synopsis Of 1620 patients routinely patch tested with Kathon CG 100 p.p.m. aqua for suspected allergic contact dermatitis, 81 (5.0%) had a positive reaction. Sixty-two reactions (3.8%) were relevant for the dermatitis for which the patient consulted the dermatologist. Most patients were females who presented with dermatitis of the hands and/or face. Forty-six per cent of the patients had become sensitized by using cosmetic products on healthy skin. The other 54% had pre-existing dermatitis, especially atopic dermatitis and irritant dermatitis. Most reactions were caused by moisturizing creams.