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Underactive thyroid disease in dogs

Like humans, dogs can also suffer from an underactive thyroid, or hypothyroidism. It is rare to see overactive thyroid disease in dogs.

Dogs produce thyroid hormone from glands in their neck, and it has a number of important functions in the body.  If the glands are not producing enough, usually as a result of the dog’s immune system attacking and destroying the glands, hypothyroidism results.

Symptoms of hypothyroidism

The most common symptoms that we see in dogs are:

  • Hair loss and skin conditions e.g. recurrent ear or skin infections.
  • Weight gain, or difficulty losing weight, despite being put on a diet.
  • Heat seeking – the dog feels the cold more.
  • Lethargy and reluctance to exercise.

The signs can be quite subtle, especially early on in the disease.


The diagnosis of hypothyroidism relies on blood tests, but unfortunately this is not always as straightforward as discovering low thyroid hormone levels as other diseases can also cause this.


Treatment consists of lifelong medication to replace the thyroid hormone. Some of the symptoms take a while to improve, but generally dogs do very well once on treatment.  The effectiveness of treatment is monitored with regular check-ups and blood tests.

If you think your dog is showing any of the symptoms of hypothyroidism a vet check is advised.  You can book by calling 01803 606059 (Torquay) or 843836 (Paignton) or book online.  We advise an annual health check for all pet dogs, as the vets often pick up things that can go un-noticed when you see your dog everyday.


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