What Is Hashimoto’s Thyroiditis? Symptoms, Causes, Diagnosis, Treatment, and Prevention

Hashimoto’s thyroiditis is a disorder in which the immune system mistakenly attacks the thyroid, which is a gland located at the base of the throat. The thyroid makes hormones that help the body use energy and work as it should. (1)

This attack causes inflammation and interferes with the thyroid gland’s ability to produce the hormones that control these bodily functions.

The disease is also known as chronic lymphocytic thyroiditis or autoimmune thyroiditis. (2)

Because Hashimoto’s thyroiditis develops very slowly over time, symptoms are usually subtle at first. Symptoms tend to become more obvious as the disease progresses. (3)

The first sign of Hashimoto’s thyroiditis is often a goiter, which is an enlargement of the thyroid gland. This may begin as painless swelling in the lower front of your neck. As time goes on, if the goiter becomes extremely large, it can become uncomfortable and possibly interfere with swallowing or breathing. (2)

Hashimoto’s thyroiditis leads to symptoms of hypothyroidism (or underactive thyroid), which may include:

• Weight gain
• Fatigue
• Sensitivity to cold temperatures
• Depression
• Problems concentrating
• Dry skin
• Brittle nails
• A puffy face
• Thinning hair
• Heavy or irregular menstrual periods
• Pain or swelling in the joints
• Constipation
• Muscle weakness

Doctors don’t know exactly what causes Hashimoto's thyroiditis. Genes may play a role, as can viral infections and hormonal changes. (2)

The following factors may increase your risk of developing Hashimoto’s thyroiditis:

Gender Women are far more likely than men to develop Hashimoto’s thyroiditis.

Age The disease is diagnosed most often in middle age.

Other Autoimmune Diseases If you have another autoimmune disease — such as rheumatoid arthritis, type 1 diabetes, or lupus — you have a higher risk of developing Hashimoto’s thyroiditis.

Family History You are at higher risk for the condition if other members of your family have thyroid or autoimmune diseases.

Your doctor will likely conduct a physical exam and use one or more of the following blood tests to diagnose Hashimoto’s thyroiditis.

Thyroid-Stimulating Hormone (TSH) Test This test measures how much TSH your pituitary gland is secreting. Higher-than-normal TSH levels indicate low thyroid function, and you may have Hashimoto’s thyroiditis.

TPO and Tg Antibody Tests When these antibodies attack the thyroid gland, they affect the production of thyroid hormone. If this test finds elevated antibody levels, it can suggest Hashimoto’s.

Free T4 Test Low levels of this hormone signal a person may have Hashimoto’s.

Your doctor may also perform an ultrasound or CT scan to get a better view of your thyroid gland.

But sometimes a person may have what’s known as subclinical hypothyroidism — meaning their TSH levels are high, or slightly high, with their free T4 being normal. In this case, their symptoms may be mild but noticeable and persistent, or they may have no symptoms at all. (4)

Subclinical hypothyroidism tends to occur early on in the disease, and may sometimes progress to what’s called overt hypothyroidism (where TSH levels are high and T4 levels are low), so your doctor will also monitor your condition in this case as well.

It’s estimated that the incidence of subclinical hypothyroidism ranges from 3 percent to 15 percent. (5)

Prognosis of Hashimoto’s Thyroiditis

With proper diagnosis and treatment, the hypothyroidism caused by Hashimoto’s can be controlled with medication, and diet and exercise may help you remain as healthy as possible for as long as possible. (6)

There’s no cure for Hashimoto’s thyroiditis, but treatments can control your symptoms. The treatment you receive will depend on test results and other factors.

If TSH and T4 tests suggest that your thyroid gland is functioning normally, you may not need any treatment, but your doctor will probably want to monitor your condition to see if it progresses. If you are experiencing subclinical hypothyroidism, you may or may not need or want treatment, but you should discuss that with your doctor.

Medication Options

Treatment usually involves taking the synthetic thyroid hormone levothyroxine daily. Levothroid and Synthroid are the two most commonly prescribed brand-name drug versions of this synthetic hormone.

Levothyroxine mimics the action of the natural thyroid hormone thyroxine (T4). It restores your hormone levels to normal and reverses the symptoms of hypothyroidism. The medicine is taken orally — at the same time each day, on an empty stomach with no other meds or food for 45 minutes — and typically has almost no side effects.

Treatment is usually continued for the rest of your life, but your dose may change over time.

You may notice some improvement within a week of starting on levothyroxine, but it may take up to six months before you experience the drug’s full effects.

Tell your doctor about all prescription, nonprescription, illegal, recreational, herbal, nutritional, or dietary drugs you’re taking before starting on levothyroxine.

And don’t skip a dose or stop using the medicine without first talking to your doctor. If you stop taking levothyroxine, your symptoms will return. If your hypothyroidism worsens and goes untreated for a long period of time, it can be potentially fatal.

Alternative and Complementary Therapies

Some people with thyroid disease report improved symptoms when they follow a gluten-free diet or a low-carbohydrate diet. Autoimmune thyroiditis has been seen to occur in people with celiac disease, and celiac disease has been seen to occur in people with autoimmune thyroiditis.

No studies have definitively confirmed a link between changes in diet and improved Hashimoto’s symptoms. Some suggest that gluten-free diets may be beneficial, but more research is needed. (7)

Prevention of Hashimoto’s Thyroiditis

Unfortunately, there is no way to prevent Hashimoto’s thyroiditis.

If left untreated, Hashimoto’s thyroiditis can cause complications, including:

Heart Problems The disease can lead to high LDL cholesterol (a contributor to coronary artery disease), heart failure, and other forms of heart disease.

Goiter (Enlarged Thyroid) Hashimoto’s thyroiditis can cause a large goiter to grow, which may interfere with swallowing or breathing.

Mental Health Issues The condition raises your risk of depression and may slow your mental function.

Miscarriage, Premature Birth, and Stillbirth These have been associated with untreated thyroid conditions. (8)

Myxedema (Severe Hypothyroidism) Some people with untreated Hashimoto’s thyroiditis develop myxedema, a rare and life-threatening form of hypothyroidism.

There’s also some evidence that women with hypothyroidism may experience problems such as lower desire and inhibited orgasm. (9)

Hashimoto’s thyroiditis affects about 1 to 2 percent of people in the United States, according to the National Institutes of Health. (2)

The disease is more common in women than in men — it occurs at least eight times more often in women than men, according to the National Institute of Diabetes and Digestive and Kidney Diseases. (10)

It can occur at any age, but is more likely to affect people between ages 40 and 60. (10)

You’re more likely to develop Hashimoto’s thyroiditis if other people in your family have it.

White people seem to be at a higher risk of developing hypothyroidism than Black people.

Research suggests that, compared with white individuals, Black individuals have lower levels of TSH hormones and the antibodies associated with hypothyroidism. (11)

In an analysis of military medical records, published in JAMA, researchers found that rates of Hashimoto’s thyroiditis were significantly lower in Black people and Asian people and Pacific Islanders, while being much higher in white people. Researchers hypothesize that the difference may be due to variations in environmental exposure, genetics, or a combination. (12)

Those with Hashimoto’s thyroiditis may be more likely to also have:

• Autoimmune hepatitis
• Addison’s disease
• Celiac disease
• Lupus
• Rheumatoid arthritis
• Pernicious anemia
• Type 1 diabetes
• Vitiligo
• Sjögren’s syndrome

American Thyroid Association