Background: Chromium and cobalt (and their compounds) are well recognized as being important causes of occupational contact dermatitis (OCD), particularly of the hands, although their exact contribution to occupational hand dermatitis varies between different studies. In some European studies, cases of chromium-related dermatitis have decreased following the addition of ferrous sulphate to cement to reduce the amount of available chromium.
Objectives: To examine, using data from the U.K. occupational skin surveillance schemes, the proportionate reported incidence and changing trends in OCD considered to be related to chromium and cobalt for the 11-year period from February 1993 to December 2004.
Methods: Surveillance data collected by the two British occupational health surveillance schemes, EPIDERM and OPRA, from February 1993 to December 2004 were studied. These are occupational health surveillance schemes in the U.K. to which physicians voluntarily and anonymously report new cases of skin disease suspected to be work related.
Results: Over the 11-year period, dermatologists reported 22 184 cases of OCD, comprising 77% of all types of occupational skin diseases that were disclosed. Chromium was recorded as being thought to play a role in 1226 (6%) of these, with cobalt identified as being likely to be implicated in 823 (4%). The numbers fluctuated on a year-on-year basis but there were no overall trends during the period of study. The male/female ratio was 5 : 1 for chromium and 1 : 1 for cobalt. Overall, the male/female ratio for OCD was 1.4 : 1. The rates of dermatitis believed to be related to both metals generally increased with age. In women, the highest rate for chromium was seen in the > 60 years age group, whereas conversely, for cobalt the rate decreased with age. For chromium-related OCD the most common occupations were builders and building contractors, bricklayers, construction workers and plasterers. For cobalt-related OCD, the commonest occupations were hairdressers/barbers, builders/building contractors, retail cash/checkout operators, machine operatives and domestic cleaners. Occupational physicians reported 15 016 cases of OCD (82% of all occupational skin diseases reported by them) for the period May 1994-December 2004. Of these, only 38 cases were thought to be related to chromium and 30 to cobalt (25 of the latter were processing labourers).
Conclusions: In this series, chromium was reported by dermatologists as potentially being involved in 6% of all cases of OCD in the U.K., and cobalt in 4%. Our data support the view that chromium-related dermatitis has an onset in later working life and often affects those in the building trades, whereas cobalt-related dermatitis seems to have an earlier onset and may affect a wide range of employments.