Q: Could my dry skin and sleepiness be caused by thyroid disease?

A: Yes. In fact, the most common sign of a thyroid condition is fatigue.

The thyroid is a small, butterfly-shaped endocrine gland at the base of the neck that regulates metabolism. Hyperthyroidism (overactive thyroid) and hypothyroidism (underactive thyroid) can cause fatigue, but for different reasons.

In hyperthyroidism, your thyroid is being overworked, causing you to feel tired. In hypothyroidism, fatigue results from the underproduction of hormones that slow metabolism and tendon reflexes.

Here's how it works. The thyroid produces two main hormones, T3 and T4, which stimulate the metabolism of almost every tissue in the body. The output of both is regulated by thyroid stimulating hormone (TSH).

Hyperthyroidism is caused by overproduction of T3 and T4 hormones. Symptoms include heart palpitations, hand tremors, nervousness, anxiety, and fatigue. Initial treatment is an anti-thyroid medicine such as methimazole or radioactive iodine therapy.

Hypothyroidism is due to underproduction of T3 and T4. Key symptoms: Dry skin and hair, swelling around the eyes, abnormal weight gain, and fatigue. Some patients can be treated with the synthetic thyroid hormone levothyroxine.

There is no known prevention for hyperthyroidism or hypothyroidism. But they can be hereditary, so knowing your family history may help identify the condition quickly. Catching thyroid disease early will help determine the best treatment to successfully manage it.

- Dr. Karen Agersborg