A Guide to Hypothyroidism in Dogs

Hypothyroidism is the most common thyroid disease in humans, affecting over 10 million Americans. Chances are you or someone you know suffers from an underactive thyroid. 

But did you know your four-legged canine might also be at risk?

This common endocrine disease occurs when your dog's thyroid isn't producing enough essential thyroid hormones to regulate their metabolism. As a result, their metabolism slows down. 

Dogs at risk for hypothyroidism 

Just like in people, hypothyroidism can affect any dog at any age. However, it is often found in middle-aged dogs (4-10 years old). 

Medium-to-large-size dog breeds also appear to be at greater risk of developing the disease than others. These breeds include:

• Golden Retriever

• Labrador Retrievers

• Cocker Spaniel

• Miniature Schnauzer

• Dachshund

• Doberman Pinscher

• Airedale Terrier

• Irish Setter

Though the reasons aren't entirely clear, spayed and neutered dogs have an increased risk of developing hypothyroidism. 

Signs and symptoms of hypothyroidism in dogs

There are several signs a dog may exhibit that could indicate he has thyroid disease. 

Symptoms of hyperthyroidism in dogs include, but are not limited to:

• Unexplained weight gain

• Obesity

• Increased thirst

• Increased urination

• Enlargement of the thyroid gland

• Vomiting

• Diarrhea

• Aggression 

• Slowed heart rate 

• Lethargy

• Decreased activity level

• Anemia

• Muscle weakness

• Cold intolerance

• Dull, thinning coat

• Hair loss

• Hyperpigmentation

• Recurring ear or skin infections

If your dog shows any of these symptoms, consult your vet as soon as possible. 

Causes of hypothyroidism in dogs

Lymphocytic thyroiditis (inflammation of the thyroid gland) and idiopathic thyroid gland atrophy (degeneration of the thyroid gland) are the two common causes of hypothyroidism in dogs. 

Though less common, dogs can also develop hypothyroidism due to:

• certain medications, like steroids

• neck injury that causes damage to the thyroid

• thyroid cancer

Diagnosing a dog with hypothyroidism 

According to The Merck Veterinary Manual, hypothyroidism is one of the most over-diagnosed diseases in dogs because it shares many similarities to other diseases. Therefore, diagnosing can be tricky. 

Your vet will look at your dog’s clinical symptoms and run some diagnostic tests. A test that measures your dog's T4 concentration levels is often a good indicator of hypothyroidism. However, the vet may perform other blood and hormone tests as well. 

Hypothyroidism treatment options for dogs 

Treatment for hypothyroidism includes a prescription medication called levothyroxine, a synthetic form of the thyroid hormone your dog is missing. 

Since hypothyroidism is treatable but not curable, your dog will need to stay on their thyroid replacement hormone for life. Your dog may require adjustments to their dosages from time to time, so it's recommended you have their blood thyroid levels checked by your vet at least yearly. 

In addition to medication, your dog should also have a healthy diet that includes amino acids, iodine, vitamins, minerals, probiotics, antioxidants, proteins, fats, and carbohydrates. Your vet can recommend the best food to feed your dog with hypothyroidism. 

Final thoughts 

Every organ in your furry friend's body is affected by their thyroid hormone and metabolism. As a result, untreated hypothyroidism can shorten your dog's lifespan and lead to overall lower quality of life. Untreated hypothyroidism in dogs can also lead to:

• high cholesterol

• slowed heart rate

• decreased immune function

• neuromuscular signs

You don't have to go into debt paying for your dog's hypothyroidism medication or other pet prescriptions. By doing a little bit of research, cost comparison inquiries, and using CareCard, you can save money on pet medications.