Occupational contact allergy to formaldehyde and formaldehyde releasers

Background: Formaldehyde allergy is common and usually derives from formaldehyde-releasing biocides in cosmetic and other products. Objectives: To analyse patterns of patch test reactions to formaldehyde and formaldehyde-releasing compounds and the sources of sensitization. Patients/Methods: At the Finnish Institute of Occupational Health, we screened the patch test files for allergic reactions to formaldehyde and 12 formaldehyde-releasing compounds. All patients with contact allergy to any of the substances were included, and their records were reviewed. Results: Between January 2001 and May 2007, we had patch tested 81 patients with formaldehyde allergy and 18 with independent allergy to some formaldehyde releaser. Of the formaldehyde allergies, 60 were new sensitizations, 25 of which were considered to be occupational. The most common source of occupational sensitization was metalworking fluids followed by creams and related products. Exposure to formaldehyde-releasing preservatives in liquid soaps and other rinse-off products was common in both occupational and non-occupational cases. Reactions to formaldehyde-releasing compounds were seen in 79% of the formaldehyde-allergic patients. Conclusions: Occupational formaldehyde allergy was common and occurred in metalworkers, hairdressers, masseurs, and workers using protective creams, detergents, and liquid soaps. When compared with studies on general dermatological patients, contact allergy to formaldehyde releasers without formaldehyde allergy was rare.