Inorganic mercury poisoning due to cosmetic cream in Hong Kong: a case series

Abstract

INTRODUCTION: Physicians might prescribe corticosteroid in addition to chelation therapy in patients with inorganic mercury poisoning with the presence of proteinuria. However, there is controversy over the efficacy of corticosteroid in treating these patients. Therefore, there is a need to study a case series to evaluate patient characteristics and treatment outcome of inorganic mercury poisoning due to cosmetic cream for skin whitening. METHODS: Cases in 2008 to 2015 were identified and reviewed using the electronic database of the Hong Kong Poison Information Centre. For inclusion, patients must have documented inorganic mercury toxicity, use of cosmetic cream, and proteinuria. Patients were classified into two groups (dimercaptosuccinic acid chelation or combination therapy of dimercaptosuccinic acid and prednisolone) according to their treatment received during period of mercury toxicity. The primary outcome of the study was the duration to proteinuria remission. Data were analysed using SPSS statistics version 22. RESULTS: Seventeen patients were included in this study: 15 (88.2%) patients were female and 13 (76.5%) patients were Southeast Asians. Of the patients, 14 (82.4%) were treated with chelation, prednisolone, or combination therapy. Comparing patients with combination therapy to chelation only, there was no significant difference in the duration to achieve proteinuria remission (67.3 ± 4.91 vs 46.8 ± 12.5 days; P=0.307). Baseline blood mercury level correlated with duration to achieve proteinuria remission (r=0.79; P=0.004). CONCLUSION: Inorganic mercury in certain skin-whitening creams can cause mercury poisoning and nephrotic syndrome. The duration of proteinuria is related to baseline blood mercury level and is not significantly affected by the addition of corticosteroid to chelation therapy.