4 Common Thyroid Problems in Dogs [+Signs, Causes & Prevention]

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vet is taking blood test from yorkie terrier in order to check his thyroid

The thyroid gland in dogs produces hormones that help to regulate metabolic processes in the body. Unfortunately, the glands can malfunction and cause different thyroid-related problems. 

The most common thyroid issues dogs may face include:

  • Lymphocytic thyroiditis
  • Idiopathic thyroid gland atrophy
  • Goiter
  • Thyroid carcinoma

In this article, we’ll review the common thyroid problems in dogs and discuss symptoms, causes, prevention, treatment, and more. After that, I’ll give you a list of common signs to watch for and common causes of thyroid issues in dogs. To help you care for your furbaby, I’ll provide some recommendations for prevention and general healthcare.

Common Thyroid Problems

Dogs experience certain conditions that can cause the thyroid gland to produce either too much (hyperthyroidism) or not enough (hypothyroidism) thyroid hormone.

Lymphocytic thyroiditis

Lymphocytic thyroiditis is an autoimmune disease in which the body’s immune system attacks and destroys the thyroid gland, thus causing hypothyroidism. This disease is the most common cause of hypothyroidism in dogs.

Usually, lymphocytic thyroiditis occurs in middle-aged dogs after at least 60-70% of normal gland tissue is destroyed.

Signs of lymphocytic thyroiditis include:

  • Obesity
  • Cold intolerance
  • Sluggishness/lethargy
  • Weakness
  • Hair loss/poor coat
  • Infertility
  • Scaly skin
  • Hyperpigmented skin 

Lymphocytic thyroiditis is caused by an autoimmune disease in dogs that triggers the body to attack the glands and destroy the healthy tissue. Large and medium-breed dogs including Doberman Pinschers, Boxers, Irish Setters, Rhodesian Ridgebacks, Dalmatians, Golden Retrievers, Beagles, and Alaskan Malamutes, are predisposed to developing the disease.

The only preventative measure for this disease is to avoid buying puppies with a family history of hypothyroidism. However, if you suspect a problem, you can request a screening test for thyroiditis to help you prepare.

Treatment for lymphocytic thyroiditis is oral thyroid replacement hormones. There is no cure. Therefore, the medication will continue for the rest of your dog’s lifetime.

Idiopathic thyroid gland atrophy

Idiopathic atrophy of the thyroid involves the replacement of the gland with adipose tissue. As a result, the thyroid cannot produce enough hormones.

Similar to lymphocytic thyroiditis, idiopathic thyroid gland atrophy commonly affects middle-aged dogs.

Signs of idiopathic thyroid gland atrophy are the same as for lymphocytic thyroiditis, including lethargy, weakness, weight gain, cold intolerance, hair loss, and skin hyperpigmentation.

The cause of idiopathic thyroid gland atrophy is unknown, but there may be a genetic component. Large and medium-breed dogs are more likely to develop signs of the disease.

Prevention of idiopathic thyroid gland atrophy involves working with a reputable breeder to make sure your puppy has no familial history of hypothyroidism.

Idiopathic thyroid gland atrophy is not curable, but it can be medically managed with daily doses of oral thyroid replacement hormones.


Goiter in dogs is a non-cancerous enlargement of the thyroid gland which can interfere with breathing, swallowing, and other bodily functions.

This condition can affect dogs at any age.

Signs of goiter include:

  • Swelling at the base of the neck
  • Difficulty swallowing
  • Shortness of breath
  • Wheezing
  • Loss of appetite
  • Sudden weight loss

The most likely causes of goiter are genetic defects, a reaction to the antibiotic trimethoprim sulfa, or congenital hypothyroidism. Certain foods, including lima beans and sweet potatoes, can also trigger goiter in dogs.

To prevent goiter, ensure your dog eats a well-balanced diet and avoid foods that may cause the condition.

Treatment for goiter focuses on addressing the underlying cause. If the goiter is too large to resolve, it will be surgically removed, along with the thyroid gland. Your dog may require hormone replacement therapy after the surgery.

Thyroid carcinoma

Thyroid carcinomas are cancerous tumors of one or both of the thyroid glands, which may cause excess release of thyroid hormones.

This condition usually affects senior dogs over the age of 9.

Signs of thyroid carcinoma in dogs include:

  • Changes in bark
  • Lethargy
  • Loss of appetite
  • Weight loss
  • Difficulty swallowing/breathing
  • Increased thirst/urination

Causes of thyroid carcinoma in dogs can include genetic or familial links, sex, age, and environmental factors. Predisposed breeds include Beagles, Boxers, Golden Retrievers, and Siberian Huskies.

Prevention of thyroid carcinoma in dogs starts by working with a reputable breeder and avoiding stock with a history of the disease.

Treatment for thyroid carcinoma in dogs is surgery as long as the tissue is minimally invasive and can be safely removed. Otherwise, the cancer can be treated with chemotherapy or radiation therapy. 

Thyroid Health Problems across the lifecycle

Thyroid health problems generally affect dogs in their middle-aged or senior years but can vary depending on the condition.

Thyroid Health Problems in Puppies

While most thyroid health problems take time to develop, there is one condition that can affect puppies. Young dogs may develop goiter or an enlarged thyroid gland.

Thyroid Health Problems in Adult Dogs

Middle-aged adults can suffer from thyroid problems that cause hypothyroidism. Lymphocytic thyroiditis usually affects dogs in their middle years. The other condition that occurs at this stage in the lifecycle is idiopathic thyroid gland atrophy.

Thyroid Health Problems in Senior Dogs

Thyroid Carcinoma is a condition that usually affects dogs in their senior years and may trigger symptoms of hyperthyroidism.

Thyroid Problem Signs Dog Parents Should Beware of

Thyroid problems in dogs share common signs depending on the condition. Knowing what to watch for can help you seek care as soon as possible.

  • Obesity
  • Cold intolerance
  • Sluggishness/lethargy
  • Hair loss/poor coat
  • Swelling at the base of the neck
  • Difficulty swallowing
  • Shortness of breath
  • Changes in bark
  • Increased thirst/urination

Common causes of Thyroid Problems

Thyroid problems share some common causes, including:

  • Genetic or breed predispositions – Large and medium-breed dogs are more commonly affected.
  • Autoimmune disease
  • Age

Thyroid Health Care Tips and Problem Prevention

Here are some tips to help you protect your dog and promote a high-quality life. 

  • Feed your dog a well-balanced diet that includes appropriate levels of iodine.
  • Schedule annual health exams and stay up-to-date on vaccinations.
  • Provide your dog with appropriate levels of exercise for his breed and age.
  • Deal with reputable breeders to select a puppy that doesn’t have a family history of thyroid problems.

The Final Woof

Certain thyroid problems can affect dogs and cause the glands to secrete too much or not enough hormone. Understanding the common conditions helps you to get the best possible care for your furbaby. While goiter can affect dogs at any age, most conditions manifest in middle-aged or senior canines. If you’re aware of common signs of trouble and practice some prevention and healthcare tips, you’ll be equipped to promote a quality life for your special pal.

Photo of author
Dr. Libby Guise earned her DVM from the University of Minnesota in 1994. After working in private practice in Wisconsin for two years, she joined the USDA as a Veterinary Medical Officer. In 2011, Libby came home to focus on raising and teaching her adoptive daughter. She lives in Wisconsin with her daughter, husband, and two furbabies: Charis, a lab-mix rescue pup, and Chesed, a Springer Spaniel.

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