Occupational dermatoses in metalworking fluid exposed workers. (II) allergic contact dermatitis

Background: Skin contact with metalworking fluid (MWF) remains a frequent cause of occupational dermatitis. However, no precise data is available about sensitization in metalworkers exposed to MWF in Korea. Objectives: The purpose of this study was to evaluate the prevalence of contact sensitivity among metalworkers who handle MWFs and to investigate the suitability of a screening test with MWFs being actually used in metalworkers. Methods: An epidemiological study was performed using a questionnaire in 771 workers in 9 departments of a motor company. 278 out of 771 workers had actual contact with MWF. Patch tests were performed in 73 metalworkers who had suspected dermatitis in relation to exposure of MWF, which was selected via interviews and dermatologic examinations. Patch tests were included with a routine series of common components of MWF (materials obtained from Chemotechnique®, Sweden), a solvent series and several dilutions of various crude MWFs (8 species). Results: Contact sensitization was established in 14 metalworkers (5% of 278). Sensitising substances were biocide (6 cases), corrosion inhibitors (2 cases), emulsifiers (2 cases), biostatic substances (1 cases) and others(4 cases). Therefore 10 out of 14 metalworkers had true occupational allergic contact dermatitis. 10 out of 73 screening patch tests showed positive reactions to MWF elements, and 9 people who were positive to MWF elements showed positive reactions to crude MWF, but 1 person did not. Conclusion: The prevalence of occupational allergic contact dermatitis (3.5% of 278) was low. The screening patch test by crude MWFs actually used in metalworkers may give false negatives. Therefore for the purpose of diagnosis of allergic contact dermatitis, we need a process of patch tests with MWF elements.