An uncommon outbreak of irritant contact dermatitis caused by rubber accelerators: a historical cohort study

Abstract

Our aim was to study the association between the rubber accelerators and predisposing factors of irritant contact dermatitis (ICD) among the semiconductor factory workers. The research design was a historical cohort study. The study population was divided into two groups: (1) the rubber accelerator exposure group, including workers who wore natural rubber finger cots containing 2,2 dibenzthiazyl disulfide (MBTS), zinc diethyldithiocarbamate (ZDEC), and zinc dibutyldithiocarbamate (ZDBC); and (2) the non-rubber accelerator exposure group, including the workers who wore finger cots with less accelerators and without ZDBC (i.e., the non-exposed group). The samples were calculated, and each group comprised 99 workers. The content of rubber accelerators in the finger cots was determined using high-performance liquid chromatography technique. Cases of ICD and the respective associated factors were collected from the medical records as well as information derived from the questionnaire. Inferential statistics using multiple regression analysis were applied and the results presented as relative risk (RR), adjusted relative risk (adjusted RR), and the 95% confidence interval (CI). The demographics of the exposed and non-exposed group were statistically different in age, duration of employment, duration of contact to rubber accelerators, underlying atopic diseases, underlying allergic rhinitis, family history of atopic diseases, and family history of allergic rhinitis. The results showed that the ICD occurred in 27 (27.3%) of workers in the exposed group compared to 4 (4.0%) of workers in the non-exposed group. The adjusted RR of rubber accelerators containing MBTS, ZDEC, and ZDBC was 9.84 (95% CI 3.70, 26.15) and the predisposing factors which associated with ICD were finger cot contact duration more than 4 years, underlying allergic rhinitis, and family history of atopic diseases [1.78 (95% CI 1.03, 3.08), 1.50 (95% CI 0.85, 2.64) and 1.97 (95% CI 1.12, 3.46), respectively], while having underlying atopic dermatitis was found to be a protective factor adjusted RR 0.62 (95% CI 0.10, 4.13). Rubber accelerators MBTS, ZDEC, and ZDBC were the causes of ICD. The possible agent was ZDBC. Other predisposing factors play less important role in this epidemic.