Occupational contact dermatitis and contact urticaria caused by epoxy resins.

Over a ten-year period (1974-1983) 542 cases of allergic occupational contact dermatitis were diagnosed in our clinic. Epoxy resins caused 71 cases (13.1%) of occupational allergic contact dermatitis (CD), and three cases (0.6%) of irritant CD. One contact urticaria was caused by an epoxy resin hardener, methyl hexahydrophthalic anhydride. Epicutaneous testing with standard epoxy resin 1% in pet. (mainly oligomer of molecular weight 340) produced allergic reactions in all the patients with allergic CD with the exception of three. These three patients had allergic reactions only to their own resins. Testing the 71 patients of allergic CD with epoxy hardeners produced allergic reactions in 19 (26.8%). None of the patients had separate delayed contact allergy to epoxy hardeners without simultaneous contact allergy to standard epoxy resin.