Abstract
A 62-year-old garbage collector who had worked for 11 years in an off-set printing factory developed infiltrative erythematous dermatitis on her forearms. The patient was positive on patch testing with 2 components of the etching solution compounded in the fountain solution used for printing；component A contained 5-chloro-2-methyl-4-isochiazolin-3-one（MCI）and 2-methyl-4-isothiazolin-3-one（MI）, and component B contained MI and 2-n-octyl-4-isothiazolin-3-one（OIT）. She also reacted positive to Kathon CG（MCI/MI, 100ppm）, MI（0.1% aq）, OIT（0.1 and 0.01%pet）, and 1,2-benzisothiazoline-3-one（BIT, 0.5%pet）. The patient’s dermatitis developed 4-months after MCI had first been added to the etching solution, and it seemed that she had become sensitized to MCI, and that simultaneous or cross sensitization to MI, OIT and BIT had also occurred.
