Occupational contact dermatitis in blue-collar workers: results from a multicentre study from the Danish Contact Dermatitis Group (2003-2012).

BACKGROUND Blue-collar workers have a high risk of occupational contact dermatitis, but epidemiological studies are scarce. OBJECTIVES To investigate allergic contact dermatitis in blue-collar workers with dermatitis registered by the Danish Contact Dermatitis Group. METHODS A retrospective analysis of patch test data from 1471 blue-collar workers and 1471 matched controls tested between 2003 and 2012 was performed. A logistic regression was used to test for associations. RESULTS The blue-collar workers often had occupational hand dermatitis (p < 0.001). Atopic dermatitis was less commonly observed among blue-collar workers (19.6%) than among controls (23.9%) (p = 0.005). Allergens with a statistically significant association with the occupational group of blue-collar workers were epoxy resins, methyldibromo glutaronitrile, 2-bromo-2-nitro-1,3-propanediol, potassium dichromate, and methylchloroisothiazolinone (MCI)/methylisothiazolinone (MI). The following occupations were additionally identified as risk factors for contact sensitization to MCI/MI and MI, epoxy resins, and potassium dichromate, respectively: painting, construction work, and tile setting/terrazzo work. CONCLUSION Contact allergy is a major problem among blue-collar workers. The data indicate a healthy worker effect among blue-collar workers diagnosed with dermatitis, as blue-collar workers were diagnosed significantly less often with atopic dermatitis than were controls.