Hashimoto’s thyroiditis is an autoimmune disorder that affects the thyroid, often slowing it down and kick starting symptoms.
Hashimoto’s is the most common cause of hypothyroidism,¹ which is the clinical term for a sluggish thyroid. However, not everyone with an underactive thyroid gland has Hashimoto’s.
What is Hashimoto’s?
Hashimoto’s thyroiditis — also known as chronic lymphocytic thyroiditis and chronic autoimmune thyroiditis — is an autoimmune disorder that damages the thyroid.
The thyroid is a small, butterfly-shaped gland located at the base of the neck and below the larynx, or voice box, and it is vital for keeping your metabolism regulated and your body healthy.
With Hashimoto’s, the immune system essentially turns on itself and goes into overdrive to kill off thyroid cells; this impairs thyroid function and decreases thyroid hormone levels, causing a number of potential symptoms throughout the body.
What causes Hashimoto’s?
No one knows what causes Hashimoto’s thyroiditis disease, but we do know that it’s one of the most common autoimmune disease,² that it runs in families and that it is much more common in women or those assigned female at birth than in men or those assigned male.³
Lymphocytic thyroiditis is diagnosed more often in people who suffer from other autoimmune conditions like celiac disease, lupus, rheumatoid arthritis, or type 1 diabetes.
Researchers believe that several elements could be at play — likely a combination of genetic factors combined with an environmental factor, or trigger, like a virus or radiation exposure.⁴
What are the symptoms of Hashimoto’s thyroiditis disease?
It’s possible to have Hashimoto’s and no symptoms. But as the autoimmune thyroid disease progresses and thyroid gland function is increasingly affected, symptoms are likely to pop up.
Common symptoms of Hashimoto’s thyroiditis can include:⁵⁶
- Weight gain
- Cold intolerance
- Exercise intolerance
- Heavy or irregular menstrual periods
- Muscle weakness and muscle pain
- Joint weakness and joint pain
- Difficulty tolerating cold temperatures
- Dry, thinning hair
- Brittle nails
- Brain fog
- Enlarged tongue
- Slower heart rate
What’s the difference between Hashimoto's thyroiditis and hypothyroidism?
Many people with hypothyroidism don’t have Hashimoto's, but everyone with Hashimoto's has hypothyroidism.
“There are many possible causes of hypothyroidism, and Hashimoto's thyroiditis is just one of them,” says Dr. Stefano Guandalini, professor emeritus at the University of Chicago Medicine. “Hypothyroidism simply means that someone has lower levels of the thyroid hormones. It is a generic term, and it does not represent a specific disease.”
Non-Hashimoto’s hypothyroidism can be caused by genetics, cancer, trauma, surgery on the thyroid gland, pregnancy, medication, viral infections and more and also affects women more than men.
How does Hashimoto's thyroiditis testing work?
If you’re experiencing Hashimoto’s symptoms or have risk factors for an underactive thyroid gland, consider visiting your doctor as soon as possible, says Dr. Guandalini. While some causes of mild hypothyroidism can course-correct without intervention, most will require monitoring or treatment. Untreated hypothyroidism is linked with an increased risk of heart failure, so it’s important to get checked out if you have symptoms.
Hashimoto’s is diagnosed with a combination of two blood tests:
- TSH test: A TSH test measures levels of thyroid-stimulating hormone (TSH) in the blood, indicating whether your thyroid function is normal, underactive (hypothyroidism) or overactive (hyperthyroidism). You can check thyroid hormone levels at a healthcare provider’s office or lab, or you can take a TSH test at home.
- Thyroid antibody test (TPOab): If your TSH tests indicate hypothyroidism, then the next step is a blood test for thyroid peroxidase antibodies (TPOab). A positive TPO antibody test may indicate that Hashimoto's is the cause of the patient's hypothyroidism.
Hashimoto's vs. Graves' disease
There are actually two autoimmune thyroid diseases that can show elevated TPO antibodies: Hashimoto's and Graves' disease. So what’s the difference?
While Hashimoto's causes hypothyroidism or an underactive thyroid gland, Graves' disease causes hyperthyroidism, or an overactive thyroid gland. Some common Graves’ symptoms are nearly opposite to Hashimoto’s, and include weight loss, frequent bowel movements, goiter and heat sensitivity.⁷
How is Hashimoto's thyroiditis treated?
There’s no cure for Hashimoto’s, but it’s a fairly manageable condition. Levothyroxine is a synthetic thyroid hormone, and is used to treat Hashimoto’s as well as garden-variety hypothyroidism. Other medications used to treat thyroid disorders may also be prescribed.
Certain lifestyle factors, including improved diet and exercise, may play a role in decreasing the severity of the disease, but thyroid hormone replacement with levothyroxine is the first line of defense.
Autoimmune thyroid diseases like Hashimoto’s are common and treatable. If you have risk factors or symptoms of Hashimoto’s, TSH and thyroid antibody blood tests can help you reach a diagnosis. Once diagnosed, work with your healthcare provider to create the best treatment plan for your health needs.