When your dog doesn’t seem like themselves, it’s easy to chalk their behavior up to a bad day or getting older. However, sometimes a hidden health issue is quietly brewing beneath the surface. One common problem we see at our veterinary hospital in NYC is hypothyroidism, a sneaky condition that can affect your dog’s energy level, weight, and skin.
Learning to recognize hypothyroidism in dogs symptoms is important so you know when to seek medical attention and treatment to manage the condition.
What Is Hypothyroidism in Dogs?
Hypothyroidism happens when your dog’s thyroid gland, a small organ with a lobe on either side of the trachea, doesn’t produce enough thyroid hormones. These hormones regulate your dog’s metabolism, affecting everything from how they burn calories to how they maintain healthy skin and fur.
When thyroid hormone levels are low, the body’s processes slow down. Dogs with hypothyroidism often seem sluggish, gain weight easily, and can develop all kinds of skin and coat issues.
With proper treatment, the condition is usually very manageable. But first, it’s crucial to recognize the hypothyroidism in dogs symptoms before things get worse.
What Causes Hypothyroidism in Dogs?
Hypothyroidism in dogs is usually due to a problem with the animal’s immune system. Over 90% of dogs with hypothyroidism have one of two conditions: lymphocytic thyroiditis or idiopathic thyroid atrophy.
Lymphocytic Thyroiditis
This autoimmune condition causes your dog’s immune system to attack the thyroid gland, resulting in inflammation and reduced hormone production.
Idiopathic Thyroid Gland Atrophy
In these cases, thyroid tissue deteriorates and is replaced by fat and connective tissue. The exact cause isn’t always known (hence “idiopathic,” which is a fancy way of saying “we’re not entirely sure why”).
Less common causes of hypothyroidism include:
- Thyroid cancer
- Pituitary gland disease (the pituitary gland controls the thyroid)
- Trauma from an external injury
- Congenital defects
- Medications that disrupt hormone balance
Some dog breeds also have a higher risk of developing the condition. Golden Retrievers, Doberman Pinschers, Boxers, Huskies, Beagles, and Cocker Spaniels are all genetically predisposed to hypothyroidism.
Hypothyroidism in Dogs Symptoms: What To Watch For
Wouldn’t it be great if your dog could tell you how they’re feeling? Unfortunately, they can’t talk, so it’s up to us to pay attention and notice changes in their behavior and appearance.
One of the biggest issues with hypothyroidism in dogs is that the symptoms creep in slowly over time. It’s easy to overlook them, too, because they can mimic the effects of normal aging or other conditions.
With that in mind, the most common signs are.
1. Lethargy
One of the hallmark signs of a thyroid issue is fatigue. Lethargy in dogs with hypothyroidism isn’t just taking longer naps. It’s a noticeable drop in activity, and they may seem less interested in play, exercise, or even getting up when the doorbell rings.
2. Weight Gain
Weight gain, even when your pet doesn’t eat more, is another red flag. Your dog might start packing on the pounds even if their diet and exercise routine haven’t changed much. A drop in thyroid hormones can lead to a sluggish metabolism, making it much harder to burn calories.
3. Hair Loss and Skin Changes
Hair loss (alopecia) is common with hypothyroidism. Your dog may have a thin, dry, and dull coat. Sometimes, the skin underneath becomes thickened, scaly, or even blackened.
Skin infections can also become a recurring problem with reduced thyroid function. Dogs with low thyroid levels have a harder time fighting off yeast and bacterial infections, leading to itchy, inflamed, or smelly skin.
4. Cold Intolerance
If your dog suddenly hates being outside in chilly weather, it may be due to hypothyroidism. Cold intolerance is common because their body isn’t producing enough heat. You might find them seeking out sunny spots or curling up under blankets more than usual.
5. Behavioral Changes
Some dogs with hypothyroidism become more anxious, depressed, or even aggressive. That sluggish feeling can affect their mood.
Diagnosing Hypothyroidism in Dogs
If you recognize several hypothyroidism in dogs symptoms, your vet will likely recommend a few blood tests to confirm the diagnosis.
Typically, they’ll measure the following:
- Total T4 (thyroxine): A low level of this thyroid hormone is often the first clue.
- Free T4 and TSH: More specific tests can help confirm hypothyroidism if the total T4 test doesn’t provide a definitive diagnosis.
However, because so many conditions have similar symptoms, it’s important to get a complete picture of your dog’s health and rule out other possibilities to confirm the hormone imbalance diagnosis.
Treating Hypothyroidism in Dogs
Fortunately, hypothyroidism is usually easy to treat. Your vet will prescribe a daily synthetic thyroid-stimulating hormone (usually levothyroxine). Most dogs show improvement within a few weeks of beginning treatment.
If you don’t get help after noticing signs of hypothyroidism in your pup, things could get rough. Untreated hypothyroidism can lead to:
- Severe obesity
- Chronic skin infections
- Heart problems
- Nerve and muscle issues
- Lowered immune function
- Infertility
In rare cases, hypothyroidism can even lead to an increased risk of a life-threatening condition called myxedema coma — medical emergency in Upper Manhattan. That’s why early recognition and treatment are so critical.
Can You Prevent Hypothyroidism in Dogs?
Unfortunately, pet parents can’t prevent hypothyroidism in dogs since so many cases are due to genetics and autoimmune conditions.
However, you can help your dog stay healthy by:
- Feeding them a balanced, high-quality diet to support overall health
- Keeping up with regular veterinary check-ups to catch subtle signs of trouble early
- Monitoring changes in behavior, coat condition, or energy levels, and discussing them with your vet
- Being aware of breed predispositions, which helps you stay extra vigilant if you own a higher-risk breed
Make an Appointment To Address Your Concerns
Nobody wants to imagine their dog struggling with a chronic illness, but canine hypothyroidism is controllable. Learning the symptoms of hypothyroidism in dogs ensures you’ll be better equipped to spot trouble early.
When it comes to diagnosing signs of illness in dogs, trust your vet to make the right call. Schedule a visit with Hudson Animal Hospital by calling 212-706-4088. With care, most dogs with hypothyroidism can live full, active, and tail-wagging lives.