Recognising the signs of hypothyroidism

Symptoms of hyperthyroidism often develop slowly over a period of time and are frequently mistaken as part of the ageing process. Some of the more noticeable signs include:

  • Changes to your dog’s behaviour
    • Your dog becoming more lethargic.
    • Unexpected and unprovoked aggression towards both animals and humans brought upon by anxiety or anxiousness.
    • Anxiety with unfamiliar situations and sounds.
  • Weight gain
    • Your dog putting on weight despite no changes in its eating habits.
  • Hair Loss
    • Hair may become brittle or thinner, easily pulled out or grows back with difficulty.
    • Hair loss often occurs on both sides of the body and occasionally on the ears and tail.
    • A hairless nasal region may also be an early symptom of hypothyroidism.
  • Skin appearance
    • Skin may become darker or produce dry or oily dandruff (seborrhoea).
    • Hypothyroidism may also cause skin infections and ear infections.
    • Some dogs take on a “tragic” appearance in the face. This is a result of water retention (oedema).
  • Fertility problems

Not all dogs react in the same way and your dog may not necessarily display all these signs. Wherever possible it is always a good idea to keep a note of the changes you see in your dog.

If you become concerned about your dog’s health and welfare you should consult your veterinary surgeon.

Diagnosing hypothyroidism

To confirm the diagnosis of hypothyroidism your veterinary surgeon will take a blood sample to measure thyroid hormone (T4) and thyroid stimulating hormone (TSH).


Sammy - Before treatment


Sammy - After 3 months of treatment