Occupational dermatoses from the manufacture of plastic composite products

Abstract

Background: Workers in the reinforced plastics and more advanced plastic composite industries are exposed to reinforcing fibers and to various chemicals used for the resinous matrix or in the finishing and assembling work of composite products. Accordingly, the workers may develop both irritant and allergic contact dermatoses. Objective: The objective was to report analyzed cases of occupational contact dermatoses diagnosed in plastic composite workers during a 20-year period. Methods: The study consists of 43 of 2,178 workers diagnosed as having an occupational skin disease from 1974 to 1993. These 43 workers were employed in the plastic composite industry or exposed to plastic composite material in their work. The patients were patch tested with the standard series and the plastics and glues series. Most patients were also patch tested with substances they handled at work. Patients with upper respiratory symptoms or patients suspected to have immediate skin allergy were also tested using prick, scratch, or scratch chamber methods and 20 common commercial environmental allergens. Low molecular weight chemicals used in the plastics composite industry were prick tested as conjugates of human serum albumin. Results: Twenty-one subjects (49%) had irritant contact dermatitis (ICD), 18 (42%) had allergic contact dermatitis (ACD), and 4 (9%) had immunologic contact urticaria. ICD was caused by the mechanical irritation of glass fiber in 18 cases (86%). The rest of the cases of ICD were caused by solvents or sawing dust from cured plastic products. Diglycidyl ether bisphenol A epoxy resin caused 13 cases of ACD. One case of ACD was caused by sensitization to the epoxy compounds triglycidyl- p-aminophenol and tetraglycidyl-4-4′-methylene dianiline, two cases were caused by cobalt naphtenate in unsaturated polyester resin, and one case was caused by phenolformaldehyde resin glue. The cases of contact urticaria were caused by natural rubber latex (three cases) and epoxy resin hardener, methyltetrahydrophthalic anhydride (MTHPA). Two patients had bronchial asthma caused by epoxy resin or its hardener MTHPA. One patient had allergic rhinitis caused by MTHPA. Immunoglobulin E-mediated allergy was verified by skin prick and radioallergosorbent tests. Conclusion: In the plastic composite industry, ICD is mostly caused by man-made mineral fibers and various solvents. ACD occurred most frequently in the industry using epoxy resin compounds. Patch tests with plastic compounds to which the workers have actually been exposed are recommended.