Thyroiditis in Dogs

Thyroiditis is also known as Hashimoto's disease and is an autoimmune condition that causes a low production of thyroid hormones in the body. Hashimoto's Disease is one of the most common causes of hypothyroidism in canines. The condition can be managed by suppressing the activity of the immune system and administering synthetic thyroid hormones to the pet.

Causes of Thyroiditis in Dogs

Thyroiditis is an immune system mediated disease and the exact causes of this condition are not known. There may be certain factors that can affect the immune system and determine it to attack its own cells, resulting in hypothyroidism. Some triggering factors may include:

  • Exposure to toxins such as cigarette smoke or poisonous metals
  • Side effects of certain drugs
  • Administration of vaccines

Autoimmune thyroiditis is among the most common causes of hypothyroidism in canines.

Symptoms of Hashimoto's Disease in Dogs

Thyroiditis or Hashimoto's disease will manifest through symptoms that are typical for dogs with a low thyroid gland function. Watch out for symptoms such as:

  • Reduced metabolism and weight gain, even if the dog eats the same amount of food or even less than usual
  • Dry mouth and mucous membranes
  • Dry coat and skin
  • Hair loss
  • Lethargy
  • Elevated fever
  • Swelling of the joints

The dog may not present any symptoms when the disease debuts, but as it advances, he may display more visible symptoms.

Diagnosing Thyroiditis in Canines

Hashimoto's disease can be diagnosed by performing a few tests that will assess the function of the thyroid gland. The levels of TSH, T3 and T4 will be measured. If the dog has hypothyroidism, these will have lower values than the normal for the dog’s breed.

To detect thyroiditis, the vet will have to perform certain tests to assess the activity of the immune system.

Dog Thyroiditis Treatment Options

The treatment for Hashimoto's disease will have to address the 2 main problems:

  • The thyroid function
  • The immune system function

The vet will administer thyroxin, which is a synthetic hormone that can regularize the dog’s metabolism and reduce the symptoms. However, the vet will also prescribe corticosteroids or other immune system suppressants, which will reduce the activity of the immune system, which will no longer attack the thyroid gland. Once the immune system is under control and the thyroid hormone levels are normal, the vet may discontinue the administration of thyroxin. The treatment with immune system suppressants will have to continue for life, as there is no other cure for Hashimoto's disease in canines. The dog will have to be monitored constantly and the dose of Prednisone can be altered.

The administration of corticosteroids over a longer period of time can lead to side effects including:

  • Reduced immunity and frequent infections
  • Kidney disease
  • Liver disease
  • Fluid retention
  • Behavioral changes

If the side effects tend to be severe, the vet may discontinue the corticosteroids. These should be discontinued gradually, to avoid adrenal insufficiency.