Dr Clifford Bloch, a paediatric endocrinologist at the University of Colourado, encountered three unusual patients last year: young boys who were growing breasts.
Aside from their gynecomastia, as the condition is called, there seemed to be nothing else unusual about the boys, who were 10, 7 and 4 years old.
But Bloch soon picked up a common thread. All were using products containing lavender or tea tree oil -a "healing balm" in one case, lavender-scented skin lotions and soap in another, and shampoo and hairstyling gel containing lavender oil in the third.
Bloch was "sharp enough to pick up on the idiopathic [unusual] nature of the condition," said Kenneth Korach, chief of laboratory reproductive and developmental toxicology at the US National Institute of Environmental Health Sciences. Korach also worked on the three cases and is an author of a report on the boys in the February 1 issue of the New England Journal of Medicine.
Results of the study were first reported last June at the annual meeting of the Endocrine Society, in Boston.
"I don't know how many paediatric endocrinologists would have the time or interest to delve into the source of this type of condition," Korach said.
Oils affected hormones
After discussing the cases with Bloch, Korach and his colleagues started experiments in which human cells were exposed to the oils. The idea was to see whether those oils mimicked the effects of the female hormone oestrogen, which stimulates breast tissue growth, or block the activity of the male hormone androgen, which inhibits growth of breast tissue.
The tests showed that the oils affected both the male and female hormones. "This combinatorial activity makes them somewhat unique as endocrine [hormone] disrupters," Korach said.
When the boys stopped using the oil-containing products, their breasts returned to normal. But how many other boys may be experiencing the same abnormal pattern because of the products they put on their skin or hair?
"It's probably a relatively rare occurrence," Korach said. "We have to await further study or analysis. Now that it is coming out in this publication, other clinicians may hear about it."
Not as rare as thought
But Bloch, who is also an associate clinical professor of medicine at the University of Colorado, said the condition is "not terribly common but not as rare as you think it might be. I have seen the same phenomenon in girls as well."
Bloch said he was initially at a loss to explain the breast growth in the first boy he saw, so he began asking the mother about anything she was putting on the boy's skin.
"She said she was using a homeopathic mixture that contained lavender oil, and that got me interested," he said. "When I saw the subsequent patients, I asked the same questions."
Bloch said his suspicions were partially confirmed when the symptoms went away when the mother stopped using the lotion. He made an attempt to isolate oestrogens from the oils and then turned to the US National Institute of Environmental Health Sciences because of its superior laboratory technology.
"They did a series of bioassays in which they took oil and cultivated it with cells," Bloch explained, clinching the case.
Korach said the experience reminded him of a study published years ago about an adult male embalmer who suddenly started growing breasts. Investigation found that he had been using an embalming fluid containing compounds in the same chemical family as the oils used by the boys, and that he had neglected to wear rubber gloves, Korach said. – (HealthDayNews)
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