Hashimoto’s disease damages your thyroid function. It’s also called chronic autoimmune lymphocytic thyroiditis. In the United States, Hashimoto’s is the most common cause of hypothyroidism (an underactive thyroid).

Your thyroid releases hormones that regulate your metabolism, body temperature, muscle strength, and many other functions of the body.

Hashimoto’s disease is an autoimmune disorder. The condition causes white blood cells and antibodies to mistakenly attack the cells of the thyroid. Doctors do not know why this happens, but some scientists believe genetic factors may be involved.

The cause of Hashimoto’s disease is not known. However, several risk factors have been identified for the disease. It is seven times more likely to occur in women than men, especially women who have been pregnant. Your risk may also be higher if you have a family history of autoimmune diseases, including:

Symptoms of Hashimoto’s are not unique to the disease. Instead, it causes the symptoms of an underactive thyroid. Signs that your thyroid isn’t working properly include:

  • constipation
  • dry, pale skin
  • hoarse voice
  • high cholesterol
  • depression
  • lower body muscle weakness
  • fatigue
  • feeling sluggish
  • cold intolerance
  • thinning hair
  • irregular or heavy periods
  • problems with fertility

You may have Hashimoto’s for many years before you experience any symptoms. The disease can progress for a long time before it causes noticeable thyroid damage.

Some people with this condition develop an enlarged thyroid. Known as a goiter, this may cause the front of your neck to become swollen. A goiter rarely causes any pain, though it may be tender when touched. However, it may make swallowing difficult, or cause your throat feel full.

Your doctor may suspect this condition if you have the symptoms of an underactive thyroid. If so, they’ll check your thyroid-stimulating hormone (TSH) levels with a blood test. This common test is one of the best ways to screen for Hashimoto’s. TSH hormone levels are high when thyroid activity is low because the body is working hard to stimulate the thyroid gland to produce more thyroid hormones.

Your doctor may also use blood tests to check your levels of:

  • other thyroid hormones
  • antibodies
  • cholesterol

These tests can help confirm your diagnosis.

Most people with Hashimoto’s need treatment. However, if your thyroid is functioning normally, your doctor may monitor you for changes.

If your thyroid isn’t producing enough hormones, you need medication. Levothyroxine is a synthetic hormone that replaces the missing thyroid hormone thyroxine (T4). It has virtually no side effects. If you need this drug, you’ll likely be on it for the rest of your life.

Regular use of levothyroxine can return your thyroid hormone levels to normal. When this happens, your symptoms will usually disappear. However, you’ll probably need regular tests to monitor your hormone levels. This allows your doctor to adjust your dose as necessary.

Things to consider

Some supplements and medications can affect your body’s ability to absorb levothyroxine. It’s important to talk to your doctor about any other medications you’re taking. Some products that are known to cause problems with levothyroxine include:

  • iron supplements
  • calcium supplements
  • proton pump inhibitors, a treatment for acid reflux
  • some cholesterol medications
  • estrogen

You may need to adjust the time of day you take your thyroid medication when taking other medicines. Certain foods may also affect absorption of this drug. Talk to your doctor about the best way for you to take thyroid medication based on your diet.

If left untreated, Hashimoto’s disease can cause complications, some of which can be severe. These can include:

  • heart problems, including heart failure
  • anemia
  • confusion and loss of consciousness
  • high cholesterol
  • decreased libido
  • depression

Hashimoto’s can also cause problems during pregnancy. Recent research suggests that women with this condition are more likely to give birth to babies with heart, brain, and kidney defects.

In order to limit these complications, it’s important to monitor thyroid function over the course of pregnancy in women who have thyroid problems. For women with no known thyroid disorders, routine thyroid screening isn’t recommended during pregnancy, according to the American College of Obstetrics and Gynecology.