Hashimoto's Thyroiditis: Symptoms, Causes, and Treatment

Medically Reviewed by Poonam Sachdev on October 26, 2023
6 min read

Also called Hashimoto's disease, Hashimoto's thyroiditis is an autoimmune disease, a disorder in which the body's immune system attacks healthy or normal cells. In people with Hashimoto's, the immune system attacks the thyroid.

Located in the front of your neck, the thyroid gland is an organ that makes hormones that control metabolism (how your body uses energy). So, thyroid hormones affect a lot of things, including your heart rate and how quickly your body uses calories from the foods you eat.

If your thyroid doesn't make enough hormones, this can lead to hypothyroidism, a condition in which the thyroid does not make enough hormones for the body's needs.

Picture of thyroid


Hashimoto's thyroiditis is named after Hakaru Hashimoto, a Japanese doctor who was the first person to describe the condition in 1912.

The exact cause of Hashimoto's is not known, but many factors are believed to play a role. They include:

Genes. People who get Hashimoto's often have family members who have thyroid disease or other autoimmune diseases. This suggests genes may play a role in who gets the disease.

Germs. A virus or bacteria may cause the immune system to attack itself.

Environment. Factors like stress or excessive radiation may play a role.

Here are some of the things that put you at a greater risk of Hashimoto's disease:

Gender. Hashimoto's affects about seven times as many women and people with female anatomy as men and people with male anatomy, suggesting that sex hormones may play a role. Furthermore, some women have thyroid problems during the first year after having a baby. Although it usually goes away, as many as 20% of these women develop Hashimoto's years later.

Age. Although it may occur in other age groups, the condition is most common in women aged 30-50 years.

Having other autoimmune diseases. Having an autoimmune disease, like rheumatoid arthritis, lupus, or type 1 diabetes, increases your risk of getting Hashimoto's.

Excessive iodine. Research suggests certain drugs and too much iodine, a trace element required by your body to make thyroid hormones, may trigger thyroid disease in susceptible people.

Radiation exposure. Increased cases of thyroid disease have been reported in people exposed to radiation, including the atomic bombs in Japan, the Chernobyl nuclear accident, and radiation treatment for a form of blood cancer called Hodgkin's disease.

Hashimoto's symptoms may be mild at first or take years to develop. The first sign of the disease is often an enlarged thyroid called a goiter. The goiter may cause the front of your neck to look swollen. A large goiter may make swallowing difficult. Other symptoms of an underactive thyroid due to Hashimoto's may include:

  • Weight gain
  • Fatigue
  • Paleness or puffiness of the face
  • Joint and muscle pain
  • Constipation
  • Inability to get warm
  • Difficulty getting pregnant
  • Hair loss or thinning and brittle hair
  • Irregular or heavy menstrual periods
  • Depression
  • Slowed heart rate
  • Muscle aches and tenderness
  • Problems with memory or concentration
  • Enlarged tongue

Because Hashimoto's thyroiditis symptoms may be similar to those of other medical conditions, it is important to see your doctor for a diagnosis.

Your doctor will check to see if you have a goiter. In addition, your doctor will likely order one or more of the following blood tests:

Hashimoto's tests

Thyroid stimulating hormone (TSH): This test checks a hormone called TSH, which is made by a small gland in the brain called the pituitary gland. When your body doesn't have enough thyroid hormones, the pituitary gland sends out TSH to tell your thyroid to make more hormones. If the TSH level in your blood is high, it means you might have hypothyroidism.

Thyroxine (T-4) test: This test measures the main thyroid hormone in your body called T-4. If your blood has too little T-4, it confirms what the TSH test found—the issue is with your thyroid itself.

Antibody test: Because other diseases beside Hashimoto's may cause hypothyroidism, the doctor has to order an antibody test to make sure what the cause of the hypothyroidism may be. If the test shows the presence of an antibody to thyroid peroxidase (a protein involved in thyroid hormone production), that's a strong sign that you have Hashimoto's thyroiditis. You might need to do more than one antibody test to confirm a Hashimoto's diagnosis.

Hashimoto's disease treatment depends on whether your thyroid is damaged enough to cause hypothyroidism. If you don't have hypothyroidism, or only a very mild case, your doctor might not prescribe any medication but instead just monitor your symptoms and check your thyroid hormone levels.

If you have hypothyroidism, you'll be given medicine in the form of a pill, gel capsule, or liquid to take. This medicine, called levothyroxine, is a chemical or synthetic version of the natural thyroid hormone T-4 and is designed to restore your normal metabolism.

Levothyroxine is available in several different strengths. The exact dose your doctor prescribes will depend on a number of factors, including:

  • Age
  • Weight
  • Severity of hypothyroidism
  • Other health problems
  • Other medicines that may interact with synthetic thyroid hormones

Six to 8 weeks after starting treatment, your doctor will order a TSH test to monitor your thyroid function and ensure you're getting the right dose. Once the dose is correct, the test will be repeated in 6 months and then in a year's time. You'll need to stay on this drug for life as there's no cure for Hashimoto's.

Because thyroid hormones act very slowly in the body, it may take a few months for symptoms to go away and your goiter to shrink. However, large goiters that do not improve may make it necessary to remove the thyroid gland.

There shouldn't be any side effects with this medication. However, you'll want to avoid taking it with certain foods, supplements, or drinks like grapefruit juice and iron supplements, which might affect how well it is absorbed. Also, if you take too much thyroid hormone, you can develop serious problems like atrial fibrillation (irregular heartbeat) and osteoporosis (brittle bones).

If the levothyroxine doesn't control all your symptoms of hypothyroidism, your doctor may add a prescription for a synthetic version of another thyroid hormone called T-3 or combine the two hormones together.

Even if you're on hormone medication, you could get a flare-up of Hashimoto's. This could happen while your doctor is trying to work out the correct dose of your medicine or if you're not taking your pills regularly. It could also happen because of a physical or emotional trigger like:

  • Lack of sleep
  • Infection
  • Something lacking in your diet
  • Stressful changes, such as a move, new job, or divorce
  • Anxiety
  • Depression

Signs of a flare-up might change from person to person, but you might see any of the following:

  • Fatigue or stress
  • Sleep problems
  • Sensitivity to heat
  • Irritability
  • Rapid heartbeat

Here are some things you can do if you experience a flare-up:

  • Make sure you take your thyroid medication every day.
  • Follow an anti-inflammatory diet. This means to eat foods that are nutrient-dense (like fruits, vegetables, nuts, lean meats, and fatty fish like salmon). Avoid processed meats, fried foods, and sodas.
  • Check your iodine level. Iodine is a mineral found in some foods, like iodized salt, seaweed, and processed meats. Your thyroid uses iodine to make thyroid hormones. If you have Hashimoto's, you might be sensitive to iodine. Talk to your doctor about this and try to reduce your iodine level if it is too high.
  • Lower your stress. Because autoimmune diseases are often triggered by stress, take steps to lessen this. Get enough rest and time to relax or be with friends.
  • Talk to your doctor or nutritionist about whether to take vitamin D and selenium. Research on whether these supplements help is mixed.

If Hashimoto's thyroiditis is not treated, you may experience the following complications:

  • Goiter. Your throat may look like it's got a stuck tennis ball inside it due to your enlarged thyroid.
  • Heart problems. Low levels of thyroid hormones may cause high levels of LDL (bad) cholesterol that increases the risk of heart disease. You may also have an irregular heartbeat and an enlarged heart.
  • Emotional problems. This includes depression.
  • Sexual problems. This includes lack of sex drive, inability to ovulate (eggs not releasing from the ovaries), erectile dysfunction, or low sperm count.
  • Pregnancy problems. If the pregnant mother has untreated Hashimoto's, the risk of a miscarriage or premature birth increases. The baby may also be born with birth defects like a cleft palate, autism, or intellectual disabilities.
  • Myxedema. In very severe but rare cases, you could develop myxedema coma if your body has been exposed to cold, sedatives, or infection and your Hashimoto's has been untreated for a long time. Symptoms include extreme drowsiness, lethargy, and then unconsciousness.