Occupational contact allergy to components of polyester resin systems.

BACKGROUND Allergic contact dermatitis caused by polyester resin is considered to be rare. OBJECTIVES To describe 11 new patients diagnosed with occupational contact allergy to components of polyester resin systems in 1994-2009. METHODS Data on occupations, patch test results, symptoms and exposure to polyester products were retrieved from patient files, covering 1994 to February 2015. RESULTS Five patients reacted to unsaturated polyester resin putties. In 3 of these cases, putties were considered to be the main cause of the dermatitis. Four patients had cobalt allergy resulting from cobalt salts that were used as accelerators in polyester resins. Three patients were sensitized to triglycidyl isocyanurate (TGIC), a cross-linker in polyester powder paints. CONCLUSIONS Two product types are of particular importance in contact allergy to polyester resin: powder paints cured by heat with TGIC as the cross-linker, and car putties. Car putties are used not only in repair car painting, but also in some industrial trades to smoothen surfaces before painting. As commercial patch test substances of polyester resin putties are lacking, patients' own products need to be tested. Cobalt salts are used in several types of polyester resin product as accelerators, and these must be considered as a possible cause of cobalt sensitization.