Thyroid disease in dogs and cats is a common hormonal issue that can cause a wide range of symptoms—from weight changes and coat problems to serious heart and metabolic effects. The thyroid gland plays a key role in regulating your pet’s metabolism, so any dysfunction can significantly impact their health and energy levels.
In this article, we’ll look at the two main types of thyroid disease in pets: hypothyroidism in dogs and hyperthyroidism in cats, including how to spot the signs, which breeds are most at risk, and how each condition is treated.
Hypothyroidism in Dogs
This condition occurs when the thyroid gland doesn’t produce enough thyroid hormone. It is one of the most common endocrine diseases in middle-aged dogs.
Common signs of hypothyroidism:
- Weight gain without an increase in appetite
- Lethargy and intolerance to cold
- Hair thinning or patchy coat
- Skin infections or dry, flaky skin
- Slow heart rate
- Behavioural changes (e.g. depression or anxiety)
Read about Cushing’s disease in dogs, which may present with some overlapping symptoms.
Susceptible breeds:
Hypothyroidism is more common in medium to large-breed dogs, particularly:
- Golden Retrievers
- Labrador Retrievers
- Doberman Pinschers
- Dachshunds
- Cocker Spaniels
- Boxers
- Great Danes
- Airedale Terriers
Diagnosis and treatment:
Diagnosis is made through blood tests that measure thyroid hormone levels. Treatment involves daily thyroid hormone tablets, which most dogs respond to very well. Regular monitoring ensures the dose remains appropriate as your dog ages or gains/loses weight.
Hyperthyroidism in Cats
Hyperthyroidism is the opposite condition—it happens when the thyroid gland overproduces thyroid hormones. This condition is especially common in older cats.
Common signs of hyperthyroidism:
- Weight loss despite increased appetite
- Vomiting or diarrhoea
- Increased thirst and urination
- Hyperactivity or restlessness
- Poor coat condition
- Rapid heartbeat or heart murmur
Concerned about changes in your senior cat? Book a wellness consult to rule out hyperthyroidism or other age-related issues. The symptoms of hyperthyroidism can overlap with diabetes.
Susceptible breeds:
Hyperthyroidism is especially common in domestic short-haired cats, but certain purebreds like:
- Siamese
- Burmese
- Himalayan
may have a slightly lower risk, possibly due to genetic differences.
Diagnosis and Treatment for Hyperthyroidism in Cats
Hyperthyroidism is diagnosed with a blood test (Total T4). Once diagnosed, there are several treatment options:
- Daily medication – most commonly tablets or a transdermal gel
- Prescription diet – a low-iodine diet may help regulate hormone levels
- Surgery – removal of the thyroid gland, suitable in selected cases
We’ll discuss the most suitable plan for your cat based on age, overall health, and your ability to administer treatment.
Why Prompt Treatment Matters
Untreated thyroid disease in dogs and cats can lead to complications like:
- Heart disease or high blood pressure
- Liver enzyme changes
- Chronic skin problems
- Poor quality of life due to discomfort, pain, or anxiety
Routine senior wellness checks help us catch thyroid problems early—often before symptoms become severe.
In Summary
Thyroid disease in dogs and cats is manageable with the right treatment and monitoring. Whether your dog is slowing down or your cat can’t seem to sit still, a simple blood test may reveal the cause.
👉 Book a wellness check at Cottage Vet Clinic today—we’re here to help your pet feel their best.
