Incidence and prevalence rates for occupational contact dermatitis in an Australian suburban area

Occupational contact dermatitis (OCD) regularly causes high levels of worker morbidity; however, this is often not reflected in available statistics. This study aimed to collect and verify OCD reports/referrals and generate disease estimates for a defined geographical area in Melbourne, Australia. Two methods of data collection were used. In the first method, 30 general practitioners (GPs), 2 dermatologists and 1 dermatology outpatient clinic within a defined area reported each worker with suspected OCD seen as part of routine practice. With the second method, workers living in the area who were referred to a tertiary referral OCD clinic were included in the study. An occupational dermatologist used a gold standard process that included diagnostic patch testing to verify suspected cases. The incidence rate for confirmed cases was 20.5 per 100,000 workers [95% confidence interval (CI): 13-32.1]. The 1-year-period prevalence rate was 34.5 per 100,000 (95% CI: 24.4-48.7). The positive predictive value (PPV) was highest for the occupational dermatology clinic referrals [63% (95% CI: 49-76%)] compared with reports from the dermatologists/dermatology outpatient clinic [55% (95% CI: 36-74%)] and from GPs [43% (95% CI: 29-59%)]. This study utilizes reports from GPs and dermatologists to provide OCD disease estimates and validation data for an OCD disease register.