Hypothyroidism in dogs: what you should know

Hypothyroidism in dogs occurs when there is a decrease of thyroid hormones in the body. Thyroid hormones are very important as they affect almost all functions of metabolism. The cause of hypothyroidism is not usually known, but we do know that most of the time the problem originates in the pituitary gland and that middle-aged to older female dogs seem to be more often affected. Hypothyroidism in cats in very rare.

Hypothyroidism in dogs: symptoms to watch out for

Symptoms associated with hypothyroidism usually develop slowly, and are often not noticed until the disease becomes quite pronounced. The most common symptoms include:

  • Gaining weight or not being able to lose weight.
  • Decrease in activity, i.e. not wanting to go for walks anymore, being not as active as usual.
  • Dogs seem to be cold all of the time, often looking for warms spots to curl up in.
  • Coat changes, including thinning of the coat, poor hair growth after being shaved, changes in coat colour and losing hair, specifically on the tail. Importantly, these changes in the coat are not associated with itchiness.
  • A ‘sad’expression.

How diagnosis is made

Diagnosis of hypothyroidism is based on the typical symptoms with confirmation via blood tests.

Hypothyroidism in dogs: treatment options

Hypothyroidism is treated with thyroid hormone supplementation. Treatment is usually lifelong and tailored to each individual patient. Regular blood tests to monitor thyroid hormone levels in the blood are used to keep supplementation levels where they should be.

Symptoms usually start improving quite quickly after treatment is started. The first improvements are often noticed in the skin, with activity levels steadily increasing as well.

If thyroid levels can be normalised dogs usually live a long and happy life, often succumbing to other illnesses, rather than hypothyroidism.

Article by Dr Morné de Wet, with contribution by Dr Annemarie Gebhardt


Department of Health COVID-19 updates available at www.sacoronavirus.co.za


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