Can exposure to cobalt from leather furniture enhance the risk for allergic contact dermatitis?

摘要

Metals - including chromium and cobalt - are the most common causes of allergic contact dermatitis (ACD). Recent studies have recognized leather articles as a new source of exposure to cobalt. Furthermore, two Danish case-studies have identified upholstery leather with cobalt content of 800-1250 mg-Co/kg as the cause of ACD. The purpose of the study was to obtain more information on the use of cobalt in leather goods and assess risk of developing skin allergy by use leather furniture available on Danish marked. In total 34 samples of leather in different colors have been obtained from three producers of furniture. Readings above the detection limit revealed the occurrence of cobalt in 5 among the 34 leather samples, with the two highest concentrations of 153 mg-Co/kg and 54 mg-Co/kg. In order to investigate leaching of cobalt from the leather and assess the exposure, those two samples have been subjected to migration analysis in artificial sweat. Derived Minimal Effect Level (DMEL) for cobalt in contact with skin of Co-sensitized persons was determined from the literature data to be in the range of 0.441 -1.95 u,g-Co/cm2. Those values were used to calculate the risk characterization ratio (RCR). The migration of cobalt from upholstery containing highest and second highest cobalt content was 0.09 u.g-Co/cm2 and 0.013 u.g-Co/cm2 respectively. The calculated RCR was below 1 for both samples (0.05-0.20 and 0.07-0.29, respectively), which indicates that there is no risk of inducing cobalt allergy nor triggering of reactions among cobalt allergies by use of investigated samples. The maximum concentration detected in upholstery leather in this study was far lower than values reported in the literature, where the furniture had been investigated as a potential source of cobalt allergy. Conclusions from this study can therefore not be generalized to any kind of leather furniture available worldwide.