Hypothyroidism in Dogs

Not Enough Thyroid Hormone Produced

Hypothyroidism, one of the more common hormone imbalances seen in dogs, occurs when the thyroid gland is not producing enough of the thyroid hormone, thyroxine. Thyroid function may simply deteriorate over time (idiopathic atrophy) or can be caused when the thyroid gland is damaged by the body’s own immune system (lymphocytic thyroiditis).  Thyroid hormone has effects on almost every cell in the body.  When not enough hormone is produced, the body’s metabolism slows down.


Signs of Hypothyroidism in Dogs


Hypothyroid pets may become lethargic, gain weight, lose hair and have skin infections.  Some hypothyroid pets can develop swelling of the face and neck, and a small percentage can develop nervous system abnormalities.  Hypothyroidism typically occurs in middle aged-to-older dogs.


Breed Predisposition and Diagnosis


Doberman Pinschers, Golden Retrievers, Irish Setters, Great Danes, Dachshunds, and Boxers are all predisposed to hypothyroidism.  The  disease is diagnosed with a blood test.  Unfortunately test results are not always clear cut and several different tests may be needed to diagnose the condition.  Sometimes repeated testing is needed.




Treatment for hypothyroidism is straightforward.  The disease is treated with an oral dose of thyroid supplementation, usually in pill form, typically twice daily.   Many owners of hypothyroid dogs notice a rapid improvement in their pet’s energy level once treatment is started although regrowth of fur can take several months.  Since the patient’s thyroid can continue to change, blood samples are taken every three months to ensure that the dosage of thyroxine is accurate.  Hypothyroidism must be managed for the rest of the dog’s life.

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