The first known case of contamination of skin-lightening cream with methylmercury was identified in July 2019 in a Mexican American woman in Sacramento, Calif., according to Anita Mudan, MD, of the department of emergency medicine at the University of California, San Francisco, and associates.
The woman, aged 47 years, sought medical care for dysesthesias and weakness in the upper extremities, the investigators wrote in a report published in Morbidity and Mortality Weekly Report.
This progressed to dysarthria, blurry vision, and unsteady gait over a 2-week period, leading to her hospitalization. Over the next 2 weeks, she declined into an agitated delirium; screening blood and urine tests detected levels of mercury exceeding the upper limit of quantification.
Oral dimercaptosuccinic acid at 10 mg/kg every 8 hours was administered via feeding tube. The California Department of Public Health (CDPH) conducted interviews with the patient’s family, discovering that the patient had used a skin-lightening cream obtained from Mexico for the past 7 years. The cream was analyzed and found to contain mercury at a concentration of 12,000 ppm. A Raman spectral analysis showed that the sample contained the organic compound methylmercury iodide.
Typically, contaminated skin-lightening creams contain inorganic mercury at levels up to 200,000 ppm; the significantly lower mercury content of the cream in this case “underscores the far higher toxicity of organic mercury compounds,” the investigators wrote.
The patient has undergone extensive chelation therapy, but remains unable to verbalize or care for herself, requiring continued tube feeding for nutritional support, Dr. Mudan and associates noted.
“CDPH is actively working to warn the public of this health risk, actively screening other skin lightening cream samples for mercury, and is investigating the case of a family member with likely exposure but less severe illness,” the investigators concluded.
The study authors reported that they had no conflicts of interest.
SOURCE: Mudan A et al. MMWR Morb Mortal Wkly Rep. 2019 Dec 20. doi: 10.15585/mmwr.mm6850a4.