Canine thyroiditis is a complicated disease. In addition to asking your veterinarian about testing and disease progression we encourage you to learn more about how owners and breeders can reduce the incidence of autoimmune thyroiditis. Below, you will find relevant articles and websites that will provide additional information as well as some frequently asked questions.
Is Canine Autoimmune Thyroiditis a problem?
In 1997 An Open Letter to All AKC Clubs, dog owners, breeders and exhibitors was issued that informed its readers that “In 1995 the AKC Delegates Committee on Canine Health Education and Research identified several health priority areas for dogs. The first concern on their list was canine hypothyroidism.” This concern is still real today as Canine Autoimmune Thyroiditis is the primary cause of Hypothyroidism in dogs. It is very prevalent in some breeds and less so in others. To check your breed refer to our breed and statistics page here
Is Canine Autoimmune Thyroiditis Lethal?
While not lethal it can cause Hypothyroidism, which has symptoms like sluggishness, obesity, skin disease, cold intolerance, hair loss, weakness, poor coat quality, and infertility. While these are certainly not as bad as death, one or all of these can negatively affect your dog’s life quality.
How can I avoid getting a dog with Canine Autoimmune Thyroiditis?
Check with the breeder or check if the dog in question has parents in the Orthopedic Foundation for Animals (OFA) database.
Can we control Canine Autoimmune Thyroiditis?
Canine Autoimmune Thyroiditis is a genetic autoimmune disease so it can be bred out or controlled through spreading awareness and testing dogs before breeding.
Is Canine Hypothyroidism Hereditary?
Hypothyroidism can be idiopathic meaning that it can have an unknown origin, but the majority of cases are caused by Canine Autoimmune Thyroiditis a genetic disorder that is Hereditary
How can I tell if my dog has Canine Autoimmune thyroiditis?
There are a number of tests to detect Canine Autoimmune Thyroiditis. T3 and T4 tests are common but not as reliable as a full panel that includes TgAA
Are there any breeds that have a higher chance of having Canine Autoimmune Thyroiditis?
Yes, some breeds have a higher chance of having Canine Autoimmune Thyroiditis than others. Most of these breeds are listed here
Is canine autoimmune thyroiditis the same as Hashimoto's disease in humans?
Technically, no. Though the human disease is also genetically transmitted, Hashimoto's disease is 5 times more common in females than males. This sex difference is not seen in canine autoimmune thyroiditis. In addition, both thyroglobulin autoantibody and thyroperoxidase autoantibody are found in humans while Thacker reported that only thyroglobulin autoantibody is found in dogs. However, the histopathology is very similar.
Autoimmune thyroiditis is reported to cause about 50% of the primary hypothyroidism in dogs. What causes the other 50%?
Recent data from Michigan State University shows that the 50% of dogs shown to have idiopathic primary hypothyroidism may actually have had autoimmune thyroiditis as the original problem. However, as the thyroid is destroyed by the lymphocytes, thyroglobulin is no longer around to stimulate the autoantibody production. Hence the dogs become TgAA negative and are placed under the classification of idiopathic hypothyroids. It appears that the end stage of autoimmune thyroiditis is "idiopathic" hypothyroidism. One can conclude from this that the majority of dogs with primary hypothyroidism have the disease because of autoimmune thyroiditis.
Is autoimmune thyroiditis (positive TgAA) the same as hypothyroidism?
No, autoimmune thyroiditis is the major cause of the disease, but many dogs may harbor the thyroiditis for years before showing clinical signs of the disease. Studies (T. Brown et al., Wayne State University) done with and animal models have shown that there are some conditions which promote the disease. One of the inducers is an increase of iodine in the diet. It appears that the thyroglobulin becomes more immunogenetic as the iodine changes the steroconfiguration of the molecule. Hence, diet and other factors can promote thyroiditis and hypothyroidism in animals that are genetically prone to the condition.
Should TgAA be tested in routine thyroid testing protocols?
A positive TgAA titer is very helpful in diagnosing primary hypothyroidism. The commercial assay available from Oxford Laboratories is sensitive and specific for autoimmune thyroiditis and can identify dogs with the presence of lymphocytic thyroiditis. Since this is the major cause of hypothyroidism, it is a valuable addition to the diagnostic profile.
How can I test my dog?
Dog breeders can test for Canine Autoimmune Thyroiditis by using the VT 20 Diagnostic Screening Kit. Simply collect a few drops of blood on the collection paper provided in the kit and return it to our laboratory for testing. This assay detects Autoimmune Thyroiditis up to two years before the onset of symptoms. For dogs that are showing symptoms of thyroid disease, consult your veterinarian for a complete thyroid panel.
Dogs can be tested at any age, however testing before one year of age is not recomended because the disease is seldom detectable prior to that time. Since hypothyroidism is an autoimmune disease, dogs can test negative at one age and develop the disease at a later time. Therefore, checking breeding dogs at the ages of 1, 2, 3, 4, 6, and 8 years is advised. If the dog does not acquire thyroid disease by 6 years of age, odds are very good that it will remain negative.
How does the VT 20 kit work?
A few drops of the dog's blood is all that is used to test for autoimmune hypothyroidism. An easy way to obtain blood is to nick the quick while trimming the dog's nails. We perform the analysis in our laboratories using a state-of-the-art enzyme immunoassay to detect antibodies to canine thyroglobulin. Samples are analyzed and the results are reported directly to you. The price of the VT 20 kit includes all testing and reporting services.
To reduce the incidence of autoimmune thyroiditis, we recommend that all dogs used for breeding be tested for this disease. Consult your veterinarian for assistance with the management of this disease and your dog's health.
How do I find a disease free dog?
- Pet owners should check with their breeders to insure that a pup’s parents are disease free. Ask your breeder for documentation that both of the pup’s parents have been tested within the past year.
- The Orthopedic Foundation for Animals also maintains a database of dogs that have been tested for thyroiditis.
- Some of the most popular breeds have a high prevalence of autoimmune thyroid disease. These include the Irish Setter, Golden Retriever, Cocker Spaniel, Shetland Sheepdog, Beagle, and Doberman breeds. You can search for the incidence of thyroiditis in any breed using the breed slider above.
- Although selecting a breed with a lower risk of disease prevalence will reduce your chances of obtaining a diseased dog, the only way to be sure is to check to see if your breeder is testing their dogs before breeding them.
- Autoimmune Thyroiditis by W. Jean Dodds, DVM
- Canine Hypothyroidism: Prevalence of Positive TgAA in 503 Laboratory Samples From Greyhounds by Raymond Nachreiner, DVM, et. Al.
- Interpreting Thyroid Test Results by MaryDeee Sist, DVM