Contact sensitizations in metalworkers with occupational dermatitis exposed to water-based metalworking fluids: results of the research project “FaSt”

Background: The composition of water-based metalworking fluids (wb MWF) is complex, and various admixtures may be added before or during usage. Wb MWF may cause irritant as well as allergic contact dermatitis. While several current case reports point towards allergens particularly related to wb MWF, systematic studies have not been performed for several years. From 1999 to 2001, a study on contact allergies among patients with occupational dermatitis (OD) called “Frühzeitige Erkennung allergener Stoffe bei beruflicher und nicht-beruflicher Exposition” (German acronym: FaSt) was conducted by the Information Network of Departments of Dermatology (IVDK), funded by the employers’ liability insurances in Germany (HVBG). Objective: The objective of FaSt was to detect sensitization patterns related to particular occupational exposures. Methods: Anamnestic and clinical data were gathered using a standardised questionnaire. Patch test results were recorded by computer within the IVDK routine procedure. In addition to descriptive statistical analyses, logistic regression analysis was performed to control the effect of potential confounders. Results: Among the 1842 OD patients in the FaSt study, there were 160 metalworkers exposed to wb MWF, whose data is presented in this paper. A specific allergen pattern of these patients can be described: most frequently, sensitizations to monoethanolamine (MEA), colophony/abietic acid, and fragrance mix were observed. Additionally, cobalt, formaldehyde, formaldehyde releasers and other biocides are important allergens in these patients. Conclusions: Preventive measures and aimed in-depth research may be based on these results. The special MWF test series have to be kept up to date based on exposure information from the MWF industry and on continuos surveillance of the target group.