Dr. Walter R. Threlfall, a veterinarian who specializes in reproductive health, was stumped when a small lap dog that had been spayed began showing signs of being in heat. Tests revealed elevated levels of estrogen, which could mean some ovary tissue was left behind when the dog was first spayed. But Dr. Threlfall had a hunch what the culprit really was. On three different visits with the dog’s owner, he asked if the pup had been exposed to an estrogen product. All three times the woman answered no, until she finally remembered using a topical hormone cream. “The dog licks it off every night,” she told her veterinarian.
“She spent lots of money on that dog, and I could have solved it the first time by telling her to get the dog off the estrogen cream,” Dr. Threlfall told the New York Times.
Prescriptions for hormone creams and sprays have nearly tripled since the early 2000s, when consumers were first made aware that a large government study found serious heart attack and cancer risks associated with oral hormone replacement therapy. As more women began using the topical estrogen products, veterinarians began noticing an alarming number of pets that had been previously fixed but began showing symptoms of being in heat. Even more concerning, pediatricians began seeing more and more children with symptoms of premature puberty.
Unintentional exposure to topical estrogen products by children and pets spurred the Food and Drug Administration to issue a warning to consumers. The agency also warned consumers about adverse events to children from unintentional exposure to testosterone cream.
It most cases, it is difficult to make the connection between the problems in pets and children, and a family member’s use of hormone cream. Most women don’t associate the cream as causing problems for others, but if precautions are not taken by the user – for example, thoroughly washing hands after use and keeping the exposed area covered – others can be adversely affected if they lick or touch skin where the product was applied.
What makes identifying the culprit even more difficult is that the doctors who prescribe the topical hormone products are not the same doctors who see cases of hormone exposure in pets and children, said Dr. Cynthia A. Stuenkel, and endocrinologist at the University of California San Diego. “We need to connect the dots between these groups so pediatricians and vets think of it early before subjecting these children and animals to extensive testing.”