The thyroid gland is in the neck. It makes a hormone called thyroxine that controls metabolism (the process of turning food into fuel). With hypothyroidism, the gland doesn’t make enough of that hormone.
It’s a common disease in dogs. It affects all breeds, but it is often found in golden retrievers, Labrador retrievers , Doberman pinschers, Irish setters, dachshunds, boxers, and cocker spaniels. It usually happens in middle-aged dogs (ages 4 to 10) of medium to large breeds. Neutered males and spayed females also have a higher risk, but vets are unsure why.
It is thought that in some cases of hypothyroidism, your dog’s immune system attacks their thyroid. Other causes are the shrinking of their thyroid and, although rare, a tumor of the thyroid gland. No matter the cause, symptoms and treatments are the same.
Symptoms
Signs of hypothyroidism include hair loss, usually on your dog’s trunk, back of the rear legs, and tail. Their coat will be dull and thin, and their skin flaky, but not itchy or red. They may also have black patches of skin. Other signs may be weight gain (despite decreased appetite), muscle loss, sluggishness, a slowed heart rate, toenail and ear infections, and intolerance to cold. It’s not widespread, but hypothyroidism is also linked to seizures, heart and blood vessel problems, and infertility.
In rare cases, if hypothyroidism is left untreated, the dog's condition could continue to deteriorate, leading to a life-threatening condition called myxedema coma.
For a diagnosis, your vet will do a series of blood tests.
Treatment
Left untreated, the disease will affect your dog’s quality of life. The good news is that it typically isn’t life-threatening. Plus, it’s fairly easy and inexpensive to treat.
Your dog will have to take oral drugs daily for the rest of their life. The drug is a manmade hormone called levothyroxine or L-thyroxine. Doses are specific to each dog.
Follow-up blood tests will be needed to ensure that the medication is doing its job.
