Chromium allergy in consecutive patients in a country where ferrous sulfate has been added to cement since 1981

Cement eczema used to be a common occupational disease in Denmark. Since 1981, ferrous sulfate has been added to all cement produced in Denmark to reduce the amount of soluble hexavalent chromate to below 2 mg/kg (2 ppm). The aim of the study was to analyse a material of consecutive chromate-sensitive patients in an urban tertiary referral centre with respect to primary cause of sensitization, in a geographical area where the risk of chromate exposure from cement had been reduced. In the 6-year period January 1989 to December 1994, a total of 4511 patients were patch tested with the European standard series, including chromate. 79 patients, 31 male and 48 female, were diagnosed as chromate sensitive. Relevant chromate exposure was established in 34 of these 79 patients. Leather was the most frequent source of chromate sensitization (19 out of 34) (47%). Chromate sensitization from cement was considered likely in 10 out of 34 subjects. Of these, 7 had been sensitized before 1981, 2 had been sensitized by non-occupational exposure to cement, and only 1 had been sensitized from occupational cement exposure in the 6-year period.