Hypothyroidism in Dogs

Hypothyroidism is a common condition in dogs that can lead to unexplained weight gain, skin and coat issues, as well as behavioral changes and reduced energy.

Hypothyroidism occurs when the thyroid gland doesn’t produce and secrete enough thyroid hormones. The thyroid gland is located in the mid-neck region near the voice box (larynx). In dogs, the thyroid gland is made up of two separate lobes that lie on either side of the windpipe (trachea). Thyroid hormones play a big role in metabolism and affect the function of many parts of the body.

This condition 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.

Causes of Hypothyroidism in Dogs

In 95 percent of cases, the direct destruction of the thyroid gland causes hypothyroidism. This destruction is usually the result of either lymphocytic thyroiditis or idiopathic atrophy of the thyroid gland. Other, rarer causes of hypothyroidism include cancer and congenital defects.

Signs of Hypothyroidism in Dogs

When the metabolic rate slows down, virtually every organ in the body is affected. Most dogs with hypothyroidism have one or more of the following signs:

• weight gain without an increase in appetite
• lethargy and lack of desire to exercise
• cold intolerance (gets cold easily)
• dry, dull hair with excessive shedding
• very thin to nearly bald hair coat
• increased dark pigmentation in the skin
• increased susceptibility and occurrence of skin and ear infections
• failure to re-grow hair after clipping or shaving
• high blood cholesterol
• slow heart rate

Treatment

The good news is this disease 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.

Left untreated, the disease will affect your dog’s quality of life.