Epidemiology of occupational hand dermatitis

Occupational skin diseases constitute about 30% of all occupational diseases worldwide and also in Germany. Thereby, occupational skin diseases take the leading position of all occupational diseases. About 90% of occupational skin diseases are eczemas which are usually located on the hands. According to estimates of the registers for occupational skin diseases in Northern Bavaria and the Saarland, Germany, which have been effective since 1990 and 1999, the incidence of occupational skin diseases is 6.7 and 6.8 per 10,000 full-time workers and year. Other incidence estimates from Western industrialized countries range between 5 and 19 cases per 10.000 full-time workers and year. Population-based estimates for a 1-year prevalence of hand dermatitis, which rely on an assessment by questionnaire, range between 6.7% in Germany and 8.9% in Nor-way. Studies, which included a skin examination for outcome assessment, e.g. revealed a point prevalence of 0.5% for cases which should be seen by a physician in a sample of 20,749 US citizens or a 1-year prevalence of 10.6% for a sample of 16,587 subjects from Sweden. According to a cross-sectional study from Denmark, school children in the age of 12 - 16 years exhibited hand eczema in 3.2% at the time of investigation and reported a 1-year prevalence of 7.3%. For the latter, the predominance of female gender was confirmed (10.1% vs. 4.6%). Epidemiological studies on occupational hand dermatitis are for several methodological reasons hardly comparable. This is due to different sample sizes and selection criteria, the use of different measures of frequency and outcome assessment including the fact that no generally accepted and validated diagnostic criteria exist. Population-based as well as studies in different occupational groups revealed a higher prevalence in women. Larger studies in food- and metal-processing industries as well as in hairdressing apprentices showed a marked increase in eczema prevalence during the 3-year period of apprenticeship. For example, prevalence of hand dermatitis increased in apprentices of food industry from East-Thuringia from 17.5% to 27.5%, in hairdressing apprentices from Northwest Germany from 12.9% to 23.9% and in apprentices of metal industry from 0 to 23%, i.e. from 8.6% to 14.1%. The latter study was performed in apprentices of the car industry and allowed to distinguish the increase in hand eczema between metalworkers (9,2% to 15.3%), blue-collar workers (8.8% to 14.1%), and white-collar workers (4.6% to 6.9%). The Prevention of Occupational Skin Disease in Hairdressers Study (POSH) clearly demonstrated that the prevalence estimates largly depend on the chosen outcome definition. For various definitions of hand eczema the prevalence at the end of apprenticeship varied between 2.7% and 23.9%. A high 3-year prevalence of 20.7% was also observed in German office workers and an expected high 1-year prevalence of 46% was reported for female cleaners from Denmark. The overall high and during apprenticeship further increasing prevalence of occupational hand dermatitis calls for intense and specific measures of prevention.