Toxic Topic: Topical Hormone Replacement

The Veterinary Community has been experiencing an increase in the number of cats and dogs with unusual symptoms. We are seeing both male and female patients affected by contact with their owner’s topical hormone replacement therapy sprays, creams, and gels.

Pet owners are not purposely exposing their pets to these topical agents, rather it is inadvertent contact. When an owner applies a product to the wrists or forearms and then holds a pet, the dog or cat has now been exposed and is probably absorbing the medication themselves. Most people don’t even consider the possibility of their pets contacting or licking these areas and exposing themselves to the products. It seems as though the public is not being warned by their healthcare professionals of the possibility of exposing children and pets to these hormone replacement products. The doctors and staff here want to bring awareness about this potential health risk.

So, what are the symptoms to look for? It seems that small dogs and puppies are most vulnerable due to them being held more often, but large and adult dogs can also be affected, as well as cats. Puppies will exhibit signs of heat at a very early age. They may have bloody vaginal discharge, grossly enlarged mammary glands and vulva, and sometimes milk production when exposed to Estrogen or Progesterone products. Adult female dogs that have been spayed may show signs of heat, enlarged mammary glands and nipples, and hair loss, when exposed to Estrogen or Progesterone products. Male dogs (intact or neutered) may develop abnormally small penises, enlarged mammary glands and/or nipples, hair loss, and possibly prostate infections when exposed to Estrogen or Progesterone products. There are also different negative effects when exposed to Testosterone products. We found one documented report of an adult male Papillon that was exposed to both Estrogen and Testosterone, used by his female and male owners. This dog had chronic inflammation of the prepuce, incontinence, enlarged nipples, hair loss, prostatic cysts, and abnormal internal structures in his reproductive organs.

Female cats exhibit signs of heat, such as vocalizing, rolling around on the floor, overly affectionate (especially liking the base of the tail scratched), and cysts adjacent to the nipples. If the dog or cat has lengthy exposure to these products, their risk of mammary cancer is heightened and/or can lead to bone marrow suppression resulting in chronic anemia. The good news is that these signs will start to resolve once the exposure is discontinued. It may take months for all the symptoms to resolve, once the causative agent is removed from any possible exposure, but they should resolve.

Please be aware that if our pets with their fur coats can be affected, infants and children are possibly at a higher risk of being adversely affected. Remember, if these products can be absorbed by children and pets, other topical medications and creams are just as likely to be absorbed as well. Please contact us if you have concerns that your pet may be contacting a topical medication that could cause adverse effects, we would be happy to answer any questions you may have.