Pet Doc: Hair loss in dogs

KEARNEY, Neb. — Many dogs experience baldness, and the Pet Doc explains why.

Pet Dr. Dennis Larsen spoke with NTV's Tim Reith about the common causes of baldness related to reproductive hormone imbalance in dogs.

Dr. Larsen said, "One of the most common causes of hair loss in dogs is from an imbalance of hormones. With the hormone imbalance alopecia occurs, which is a medical term for hair loss. There are a lot of reasons why a dog might develop hair loss but let’s talk about reproductive hormonal imbalance as a reason for the hair loss.

"Estrogen is produced by the female dog, mainly in her ovaries. In females there are two possibilities of estrogen related hair loss. One is when there is too little estrogen hormone in her body. When females are spayed usually their ovaries are also removed but she produces enough estrogen in her body to maintain adequate estrogen levels. Occasionally though, she does not produce enough estrogen to maintain adequate estrogen levels, and she becomes low on estrogen, called hypoestrogenism. The other estrogen causing hair loss in females is when their ovaries develop cysts on them, which raises the estrogen levels higher than normal, this is called hyperestrogrenism.

"Even though estrogen is a female hormone, in males there are certain instances where they can produce estrogen. One is a condition where the intact male develops testicular cancer and at times the testicle changes from making testosterone, the male hormone, and instead makes estrogen, in excessive amounts. Another cause of too much estrogen in the male dog is when one or both testicles do not descend into the scrotum when the puppies are very young, like they normally would but rather one or both remain in the abdomen, a condition called cryptorchidism, the testicle that is in the abdomen tends to produce estrogen rather than the male hormone testosterone. The male is more sensitive to excessive estrogen than the female and it does not take a lot of estrogen to create a hormonal imbalance which can result in hair loss, as well as other health issues.

"The male dog produces hormones called androgens and testoterone is the main androgen. Androgen (testosterone) imbalance only affects the male dog, whereas estrogen imbalance issues can be in either the male or female dog. When the androgen hormones are out of balance it is because they are too high. Androgens are made in the testicles so the issue of too much androgen occurs in the intact male dog. Usually there are two possibilities with too much androgen, one being a testicular tumor and the second being when the testicle does not descend from the abdomen as it should when the male puppy is still of nursing age. To surmise, an abnormal testicle can either produce too much estrogen or testosterone. The result is alpoecia, hair loss, which is hormonally driven.

"When either the male of female dog is intact, veterinarians recommend to spay or neuter them. In the case of cryptorchidism, the testicle needs to be removed. In the female if her body has too low an estrogen level then estrogen supplement is given."

Click the above video to learn more.