Autoimmune thyroiditis, also called lymphocytic thyroiditis, is an immune-mediated disease characterized by progressive distruction of the thyroid gland. It occurs when T-lymphocytes, a type of white blood cells derived from the thymus gland which is responsible for fighting disease and infection, become programmed to destroy the thyroid gland.6 The thyroid gland sits on the throat below the larynx. Its function is to produce hormones that control metabolism. Because thyroid hormones play a role in the metabolic function of all cells, the symptoms affect including blood, neuromuscular, skin, circulatory, gastrointestinal, and reproductive systems. Early in the disease, the disorder can be identified through blood tests. Although the disease can be treated with thyroid hormones, it often leads to hypothyroidism. A large number of dog skin disorders are caused by thyroid diseases. Canine autoimmune thyroid disease is very similar and often identical to Hashimoto's thyroiditis in humans.6
Autoimmune thyroiditis has now been identified in more than 50 breeds. The condition is heritable in those breeds that have been studied, and progression to hypothyroidism, if it occurs, can be slow. Factors that influence the progression from subclinical thyroiditis to hypothyroidism in dogs are still to be identified. The disease is particularly often seen in the Akita, Airedale Terrier, Beagle, Borzoi, Boxer, Chow Chow, Cocker Spaniel, Dachshund, Doberman Pinscher, German Shepherd Dog, Golden Retriever, Great Dane, Irish Setter, Maltese, Newfoundland, Old English Sheepdog (Bobtail), Poodle, Rottweiler, Shetland Sheepdog, and Skye Terrier. The presence of anti-thyroid antibodies in the dog's blood or tissues marks the disease, during which the dog becomes susceptible to immune-mediated and other diseases. Thyroglobulin autoantibody (TGAA) is measured to detect lymphocytic thyroiditis, although positive results may also suggest other diseases, such as hypoadrenocorticism and diabetes mellitus.5 The Orthopedic Foundation For Animals (OFA) and The American Spaniel Club maintain a registry for Cockers and other dogs that have been tested for autoimmune thyroiditis. Based on their statistics, Cockers are about the sixteenth most affected breed. According to D. Caroline Coile, author of "The Cocker Spaniel Book," screening should begin at 2 years of age and continue every year or other year through 8 years of age.
Great Dane dog breed is predisposed to autoimmune thyroiditis.
- Margaret Williams. Irish Setter
- Graham PA, Nachreiner RF, Refsal KR, Provencher-Bolliger AL. Vet Clin North Am Small Anim Pract. 2001 Sep;31(5):915-33. Lymphocytic thyroiditis
- Wendy Volhard, Kerry Brown. Holistic Guide for a Healthy Dog
- Jackie Isabell. Genetics: An Introduction for Dog Breeders
- Steven L. Stockham, Michael Alan Scott. Fundamentals of veterinary clinical pathology
- The Canine Thyroid Epidemic. W Jean Dodds, Diana Laverdure