• Also Known As:
  • Chronic Lymphocytic Thyroiditis
  • Autoimmune Thyroiditis
  • Lymphocytic Thyroiditis
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What is Hashimoto thyroiditis?

Hashimoto thyroiditis is the most common cause of thyroid gland inflammation (thyroiditis) and the most frequent cause of underactive thyroid (hypothyroidism) in the U.S. It results from an autoimmune disorder.

The thyroid is a small butterfly-shaped gland that lies flat against the windpipe at the base of the throat. It produces the hormones thyroxine (T4) and triiodothyronine (T3) that play an important role in controlling the rate at which your body uses energy (metabolism).

Normally, the body’s natural defenses (immune system) protects you from foreign invaders, such as viruses or bacteria, through recognition and removal by antibodies. With Hashimoto thyroiditis, the immune system produces autoantibodies against the body’s own tissues or organs that attack the thyroid gland. This damages the thyroid gland so that it does not make enough thyroid hormone, leading to symptoms of hypothyroidism. The thyroid can become enlarged (called a goiter), firm, and rubbery but not usually tender.

In the U.S., Hashimoto thyroiditis occurs at a rate of 3.5 per 1,000 women per year and 0.8 per 1,000 men per year. It can affect anyone at any age but occurs most often in women between 30 and 50 years of age. In fact, women are 10-15 times more likely to develop Hashimoto thyroiditis than men.

People with a family history of thyroid diseases or who have another autoimmune disease, such as type 1 diabetes, adrenal insufficiency, rheumatoid arthritis, celiac disease, pernicious anemia or lupus, are at increased risk of developing Hashimoto thyroiditis.


About Hashimoto thyroiditis

Signs and Symptoms

If you have Hashimoto thyroiditis, you may not have any symptoms for several years, but eventually you may experience some degree of hypothyroidism that worsens over time.

Signs and symptoms may include:

  • Constipation
  • Depression
  • Dry skin
  • Tiredness, fatigue
  • Forgetfulness
  • Cold intolerance
  • Menstrual irregularities, heavy and excessive bleeding
  • Muscle and joint pain
  • Muscle weakness
  • Thinning hair
  • Voice hoarseness and/or difficulty swallowing
  • Weight gain
  • For pregnant women, increased risk of miscarriage


Testing is performed to evaluate the health of your thyroid, diagnose Hashimoto thyroiditis, and monitor treatment.

Laboratory Tests

One or more of the following blood tests may be performed to determine whether your thyroid is functioning properly and to monitor thyroid function and hormone production:

Additional tests may be used to detect autoantibodies directed against the thyroid and to help diagnose Hashimoto thyroiditis:

  • Anti-thyroid peroxidase antibody (anti-TPO, see Thyroid Antibodies) — this test detects autoantibodies that target a protein found in thyroid cells. Most people with Hashimoto thyroiditis have these antibodies and people who have hypothyroidism caused by other conditions do not. However, some people without hypothyroidism can have these antibodies.
  • Antithyroglobulin antibody (TgAb) — this test detects autoantibodies against thyroglobulin, the storage form of thyroid hormone. A positive result may indicate Hashimoto thyroiditis. While thyroglobulin antibodies are often positive, they are not as sensitive or specific as anti-TPO so they are not routinely ordered.

If you have a very mild form of Hashimoto thyroiditis, you may not have thyroid antibodies present in your blood.

Non-Laboratory Tests

If you have signs and symptoms of Hashimoto thyroiditis, but you don’t have autoantibodies in your blood, your healthcare provider might order an ultrasound exam of your thyroid. Ultrasound uses sound waves to create images of the thyroid, showing the size of your thyroid and other features of Hashimoto’s disease. Ultrasound also can rule out other causes of an enlarged thyroid, such as thyroid nodules.


There is no cure for Hashimoto thyroiditis, but the disorder can be managed.

  • No treatment may be required when thyroid hormone levels (T4 and T3) are normal and you are not experiencing significant symptoms.
  • Thyroid hormone replacement therapy is typically necessary when thyroid hormone levels are significantly decreased and symptoms begin to emerge or worsen. You may be treated with synthetic (man-made) T4 called levothyroxine that can be taken as a pill. This medication replaces the T4 your thyroid cannot make, and you will likely need to take this medication for the rest of your life. You will be closely monitored (usually with a TSH test) and your thyroid hormone replacement therapy adjusted as necessary.

View Sources

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Johns Hopkins Medicine. Hashimoto’s thyroiditis. Available online at https://www.hopkinsmedicine.org/health/conditions-and-diseases/hashimotos-thyroiditis. Accessed July 29, 2019.

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(October 18, 2018) U.S. Department of Health & Human Services, Office on Women’s Health, Hashimoto’s Disease. Available at https://www.womenshealth.gov/a-z-topics/hashimotos-disease. Accessed October 2019.

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