Thyroid Problems In Dogs: A Guide to Hypothyroidism Everything You Need To Know About Hypothyroidism in Dogs

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Hypothyroidism and hyperthyroidism can both affect dogs, though one is much more common. Learn everything you need to know about possible thyroid issues in dogs.

Thyroid problems in dogs occur in mid to later life. Dogs primarily suffer from hypothyroidism, which means the thyroid gland is not producing enough of its body-regulating hormones. If caught early, hypothyroidism is a condition that is manageable and treatable. The thyroid can also produce an excess of these hormones, and in that case, the condition is called hyperthyroidim, but this is a type of thyroid problem that’s extremely rare in dogs.

What’s a Thyroid?

The thyroid a little gland, shaped a bit like a bowtie, that lives in the neck of every dog. The thyroid secretes hormones called thyroxine and triiodothyronine. These hormones help to control the rate of a dog’s metabolism. Thyroxine and triiodothyronine can also affect other important bodily functions and organs. Humans, cats, and other animals also have this gland, and we all rely on our thyroids equally.

What Is Hypothyroidism in Dogs?

Hypothyroidism in dogs is generally caused by a genetic autoimmune disease. A dog is hypothyroid when their thyroid does not produce enough metabolism-regulating hormones. This deficiency, if left untreated, can lead to a host of other debilitating diseases including corneal ulcers, anemia, and a devastating disease called adult-onset megaesophagus, which will eventually lead to death. In the shorter term, your dog is bound to be lethargic and unhappy.

Can All Dogs Become Hypothyroid?

Any dog can develop hypothyroidism, but it is more prevalent among larger dogs. Typical onset occurs between 4 and 5 years of age, but some dogs may develop the condition earlier in life. Certain breeds are more predisposed than others to hypothyroidism, and these breeds include Dobermans, Greyhounds, Golden and Labrador Retrievers, and Cocker Spaniels.

Common Signs of Thyroid Problems in Dogs

  • Weight gain without a change in diet is the most common symptom
  • Lack of energy, extra naps, and a lack of interest in physical activities that used to interest them
  • Apparent depression, paired with behavioral changes like anxiety or aggression
  • Skin problems, especially in which fur becomes dry and brittle and begins to shed excessively

Diagnosis of Thyroid Problems in Dogs

After you share these symptoms with your vet, they may wish to do a panel of blood tests. Your vet will want to check the levels of thyroid hormone concentration in your dog’s blood.

The primary thyroid tests are called T4 (for thyroxine), and T3 (for the other thyroid hormone, triiodothyronine). If these tests are inconclusive, your vet may expand the diagnostic to include T4 Free or TSH tests, which are a bit more in depth.

Your vet may also wish to do a full blood panel to rule out other ailments.

Treatment of Thyroid Problems in Dogs

Hypothyroid dogs can be treated with thyroid hormone replacement drugs. The most common thyroid drug for dogs is Levothyroxine, which is the main ingredient in several brand name drugs, like Soloxine. Pills are prescribed based on the weight of your pet, and the level of hormones that need replacing. The pill is typically administered once or twice a day, and can be hidden inside treats or mixed with food.

Medications like Soloxine will need to be dispensed every day for the rest of the dog’s life, but sick dogs should show improvement in 10 days to 3 weeks. As the Levothyroxine is absorbed into the bloodstream, it will carry out the tasks that a thyroid hormone usually would. Your dog’s vitality should return fairly quickly.

Dogs should have their T4 levels tested regularly, especially in the first few months, to make sure doses are right.

What About Hyperthyroidism?

Hyperthyroidism, common among cats and humans, is rare in dogs. If hyperthyroidism occurs in dogs, it’s usually the result of over medicating hypothyroidism. This can usually be corrected through adjusting the dose of the medication. To avoid this altogether, a dog on hypothyroid drugs should have their blood tested regularly, to ensure levels of thyroxine are consistent.

Geriatric dogs may develop hyperthyroid as a result of carcinoma of the thyroid gland. Treatments for this condition vary. Symptoms of an overactive thyroid in dogs include weight loss, hyperactivity, irritability, dull brittle coat, and an inability to relax.

More on Dog Health

Signs of Strong Dental Health in Dogs
What's Your Dog's Ideal Weight?
Recognizing if Your Pet is Overweight

This information is for informational purposes only and is not meant as a substitute for the professional advice of, or diagnosis or treatment by, your veterinarian with respect to your pet. It has, however, been verified by a licensed veterinarian for accuracy.

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