A Sacramento woman was seriously and permanently injured by using a skin-lightening cream from Mexico that was tainted with an extremely toxic form of mercury, public health officials say.
Her case is the first poisoning with methylmercury — a chemical compound created when mercury reacts to certain bacteria in the environment — in the United States in 50 years, according to a team of doctors who treated her at UCSF. One other person also was exposed to methylmercury from the same skin cream, but her symptoms were much less severe.
Though no other exposures have been reported, public health officials said the Sacramento case raises concerns that similarly tainted products could be entering the state.
Skin-lightening creams from Mexico have long been known to contain mercury, and poisoning cases regularly have been reported. But the Sacramento case was remarkable for the severity of illness. The 47-year-old woman was hospitalized in July, and five months later she is still not able to feed or otherwise care for herself.
“If there are other cases, this will be quite a dangerous outbreak,” said Dr. Paul Blanc, chief of occupational and environmental health at UCSF, who co-authored a report on the Sacramento case that was published last week.
Public health officials said people can avoid mercury poisoning by using products that are purchased from known brands and retailers, such as Walgreens and Target. Products should come in well-labeled containers that have a protective seal over the cream.
Methylmercury is far more toxic to humans than the liquid mercury that has in the past been used in everything from thermometers to dental fillings. Exposure to all kinds of mercury can harm the brain and nervous system, but methylmecury is especially dangerous.
Symptoms of mercury poisoning include difficulty concentrating, memory loss, anxiety, insomnia, headaches, tremors, numbness or tingling in the hands, feet or around the lips, and weakness in arms or legs.
The Sacramento woman had been using a skin-lightening cream from Mexico for seven years, but became ill only last summer. She first sought treatment for weakness in her arms and dysesthesias, which is a form of nerve damage that causes unpleasant sensations like itching or pain.
Over the next two weeks, her vision became blurry and she had trouble walking. After she was hospitalized for those symptoms, her condition worsened to “agitated delirium,” according to the report on her case released by the Centers for Disease Control and Prevention.
Doctors quickly determined she had suffered mercury poisoning, and tried to treat her with a therapy to remove the mercury from her blood. The process worked, but the woman’s symptoms did not improve.
She was transferred to UCSF in September, and it was there that doctors ran more specialized tests on the skin cream the woman had used. Those tests, which were done at state public health department labs, found methylmercury.
“No one knows why this methylmercury got put in, but the assumption would be that somebody was intentionally adding mercury but didn’t realize there was difference in the forms of mercury,” Blanc said.
The last methylmercury poisoning in the United States was in 1969, involving two children and a young adult from one family who got sick after eating mercury-contaminated pork. All three victims suffered permanent vision loss and other physical disabilities. The most seriously injured, an 8-year-old girl, remained in a long-term care facility in a near-coma more than a year after the mercury exposure.
In addition, the three victims’ mother, who had eaten the same pork while pregnant but was not harmed, had a baby who suffered developmental problems that were thought to have been caused by mercury exposure.
The contamination in those cases came from animals that had been fed grains that were treated with methylmercury as a fungicide. By then, methylmercury was known to be toxic to humans and the family’s exposure was considered an accident.
Now, concern around methlymercury exposure mostly is focused on seafood consumption, and typically only for people who eat a lot of fish or who eat types of seafood known to contain high levels of mercury. The health risks in those cases tend to be more subtle, such as mild cognitive impairment.
It’s not clear whether the Sacramento case was a singular accident or if there are more tainted products circulating. The woman had purchased a product labeled as Ponds Rejuveness, to which had been added the methylmercury. Skin-lightening creams imported from Mexico often contain mercury, which bleaches the skin, but not the extremely toxic compound.
Even mercury alone can be dangerous. In the past decade, the California Department of Public Health has reported at least 60 cases of mercury poisoning linked to skin creams. In one 2014 case, a 20-month-old child was exposed to mercury through the mother’s skin cream.
The baby was diagnosed after having trouble walking, sleeping and eating, and the child later needed a feeding tube. Eventually 40 more people, half of whom were children, were found to have been exposed to mercury from the same skin cream. Many of the families had to dispose of personal items, including furniture, because they were contaminated.
“This is all in the same name of making yourself look white, which adds a whole other disturbing level to these cases,” said Dr. Craig Smollin, medical director of the San Francisco division of California Poison Control, who also helped treat the Sacramento woman.
“We’re all hopeful this was just a one-off case and we won’t see more of it,” Smollin said. “But people in these communities, especially immigrant communities, do not necessarily perceive these creams as being a risk. We need to make sure they’re educated about the potential dangers.”