Contact allergy in the cleaning industry: analysis of contact allergy surveillance data of the Information Network of Departments of Dermatology

Background. Occupational contact allergy is a common problem in the cleaning industry. Objectives. To identify the most frequent occupation-associated allergens and time trends in contact allergy in female cleaners. Methods. We analysed the patch test data concerning 803 female cleaners, who were evaluated for occupational contact dermatitis in 45 dermatological departments contributing to the Information Network of Departments of Dermatology (IVDK) from 1996 to 2009. Female patients, except cleaners, with occupational dermatitis (n = 14 494) and female controls without occupational dermatitis (n = 64 736) patch tested during this time period formed the control groups. Results. One hundred and fifty-six (19.4%) cleaners had past or present atopic dermatitis. Six hundred and fifty-five (81.6%) cleaners suffered from occupational hand dermatitis. Allergic contact dermatitis was diagnosed in 249 (31%) of the cleaners. As compared with the control group without occupational dermatitis, female cleaners were significantly more often sensitized to occupationally relevant allergens such as rubber additives, especially thiurams [11.6%, 95% confidence interval (CI) 9.1-14.1 vs. 1.5%, 95% CI 1.4-1.6], zinc diethyldithiocarbamate (3.4%, 95% CI 2.1-4.7 vs. 0.4, 95% CI 0.3-0.4), and mercaptobenzothiazole (1.8, 95% CI 0.7-2.9 vs. 0.5, 95% CI 0.4-0.6), as well as formaldehyde (3.4, 95% CI 2.0-4.7 vs. 1.4%, 95% CI 1.3-1.5). No differences were seen in patterns of sensitization to occupational allergens in younger (<= 40 years of age) and older (>40 years of age) female cleaners. Conclusion. Formaldehyde and rubber additives such as thiurams, zinc diethyldithiocarbamate and mercaptobenzothiazole are occupationally relevant allergens in female cleaners. Prevention strategies are needed to address the problem.