Feline Thyroid Symptoms

The most common feline thyroid problems may be hyperthyroidism and hypothyroidism. The cat’s body produces thyroid hormones and when these are in excess or in deficit, the cat will have a thyroid problem. The excessive secretion of thyroid hormones is more frequent in felines.

The thyroid is a small gland located in the neck area, being in charge of regulating the cat’s metabolism. When its activity is affected, the cat will display different symptoms such as weight gain or weight loss and appetite changes. As a cat owner, you have to watch out for any symptoms of thyroid disease, as an early detection of a problem can prevent further complications.

Weight Changes

Weight loss is a symptom of hyperthyroidism; the cat may lose significant amounts of weight. The cat may also have an increased appetite, but still lose weight. In severe cases, the cat may lose muscle mass also.

On the other hand, if the cat has hypothyroidism, he is likely to gain weight even if he eats the same amounts of food.

Vomiting and Diarrhea

Vomiting and diarrhea may occur in cats with hyperthyroidism. Cats with hypothyroidism may vomit, but will suffer from constipation more often.

Skin and Coat Changes

A thyroid problem will cause the cat to have a dull and coarse coat. The cat may lose significant amounts of hair, but there will be no bald patches, but the coat will get thinner.

The skin will be dry and flaky if the cat suffers from hypothyroidism. An excess of thyroid hormones may lead to an oily skin with acne and common skin infections.

Behavior Changes

Cats with hypothyroidism will be less active and sleep more. Hiding behavior is also common and there will also be a general lack of interest in food, games or activities.

On the other hand, cats with hyperthyroidism will be hyperactive, may be easily irritable and restless.

Both the hypo and hyperthyroidism will trigger the cat’s aggressiveness.

General Weakness

Cats with thyroid problems will have a state of general weakness.

Increased Thirst and Urination

The increased thirst and urination is specific for cats with hyperthyroidism. You will notice that you will have to fill up the cat’s water bowl several times per day and the amounts of urine will also increase.

Breathing Problems

Hyperthyroidism can speed up the heart rate and this may cause also breathing problems. The cat will breathe superficially.


The fast heart rate in cats with an excess of thyroid hormones may also cause shaking.

Hyperthyroidism will cause the other organs in the body to work faster and this may lead to heart, kidney or liver problems. Thyrotoxic cardiomyopathy is a common heart issue directly linked to hyperthyroidism.

On the other hand, if hypothyroidism is left untreated, it will lead to weight gain and obesity and a number of conditions that may arise due to additional weight: heart problems, diabetes or arthritis.

You should monitor your cat and if you notice any thyroid problem symptoms, consult the vet. The hormone levels can return to normal levels with medication.