Hashimoto’s thyroiditis, also known as chronic lymphocytic thyroiditis or Hashimoto’s disease, is an autoimmune condition in which the immune system attacks healthy thyroid cells and gradually destroys the thyroid gland. (Source) A Hashimoto’s flare-up is defined by an increase in symptoms of Hashimoto’s thyroiditis. Both physical and mental symptoms can manifest.

Signs and Symptoms of Hashimoto’s Thyroiditis 

Symptoms of Hashimoto’s thyroiditis may not be noticeable at first and can progress for years. Eventually the thyroid may be damaged enough to cause a decrease in thyroid hormone levels in the blood, known as hypothyroidism. 

Possible physical symptoms of hypothyroidism include:

• Increased fatigue (tiredness)
• Muscle and joint pain, aches, or weakness
• Heaviness or feeling as if your body is weighed down
• Dizziness
• Sensitivity to cold
• Switching between feeling extremely hot and cold
• Weight gain
• Constipation
• Hair loss
• Brittle nails
• Pale and dry skin
• Slow heart rate (bradycardia)
• Enlarged thyroid (goiter)
• Irregular or heavy menstrual periods
• Heart palpitations

Neurological and mental symptoms of hypothyroidism may include:

• Brain fog
• Migraines
• Difficulties with memory
• Mood swings
• Anxiety
• Depression

Hyperthyroidism, an overactive thyroid, may also present in the early stages of Hashimoto’s. This occurs when inflammation of the thyroid gland causes too much thyroxine, a hormone secreted by the thyroid gland, to be produced. (Source) 

Symptoms may include:

• Increased metabolism
• Unexplained weight loss
• Rapid or irregular heartbeat
• Sweating
• Nervousness
• Irritability
• Mood swings
• Difficulty sleeping
• Shaky hands
• Frequent bowel movements or diarrhea
• Goiter

Hashimoto's Thyroiditis vs. Hypothyroidism

Hashimoto’s thyroiditis and hypothyroidism, or thyroid hormone deficiency, are similar conditions. Hashimoto’s disease begins with inflammation of the thyroid gland and often leads to hypothyroidism as the thyroid gland is damaged. Until thyroid levels start falling, there may be no noticeable symptoms of Hashimoto’s disease. However, having Hashimoto's thyroiditis does not necessarily guarantee experiencing hypothyroidism.

Although Hashimoto’s disease is the most common cause of hypothyroidism, other causes include over-response to anti-thyroid medication, thyroid surgery, radiation therapy, medications such as lithium, and other autoimmune disorders. (Source) 

Length of Hashimoto's Flare-Ups

Hashimoto’s flare-ups typically last for a few days or weeks. If flare-ups last longer than this time frame, this may actually be a permanent dropping of thyroid hormone levels.

Causes and Triggers of Hashimoto’s Flare-Ups

There are several causes of Hashimoto’s flare-ups, and these differ from person to person. However, some common triggers for changes in thyroid function include: 

• Drinking alcohol (Source)
• Pregnancy (Source)
• Stress (Source)

Hashimoto’s and diet

Diet also plays an essential role in Hashimoto’s disease. Iodine and selenium are vital to thyroid function, so people with Hashimoto’s thyroiditis should maintain an adequate amount of these nutrients in their diet. Zinc deficiency has also been associated with Hashimoto’s thyroiditis, and zinc supplementation improved thyroid hormone levels in people with goiter, an enlarged thyroid gland. (Source) Vitamin D and Vitamin B12 deficiencies have also been observed in people with Hashimoto’s thyroiditis. (Source, Source)

Hashimoto’s and medications

Some medications and supplements can also interfere with thyroid function or with absorption of levothyroxine, the synthetic thyroid hormone used to treat hypothyroidism. These include: 

• Calcium or iron supplements
• Antacids
• Estrogens found in contraceptive pills or hormone replacement therapy (HRT)
• Cholesterol-lowering drugs like cholestyramine and colestipol
• Rifampicin (antibiotic)
• Sucralfate (ulcer medication)
• Seizure medicines such as phenytoin and carbamazepine

Adjusting the dosage of levothyroxine or changing the time of day when you take other medications can help reduce these effects. (Source, Source)

Hashimoto’s and stress

The relationship between stress and function of the thyroid in Hashimoto’s thyroiditis is not fully understood. However, stress has both direct and indirect impacts on the immune system, which may contribute to susceptibility or resistance to thyroid autoimmunity. (Source)

Common stressors include emotional stresses with family or relationships; physical stress like injuries, surgery or illness; and life changes, such as pregnancy or moving cities. Stress management techniques, such as meditation, may help alleviate stress and improve health.

Managing Hashimoto’s Thyroiditis

Hashimoto’s thyroiditis is typically treated with levothyroxine, a synthetic form of thyroid hormone. Taking the correct dosage of levothyroxine balances hormone levels and prevents Hashimoto’s flare-ups. In addition to medication, there are other ways to manage Hashimoto's.

Managing Hashimoto’s with an anti-inflammatory diet

It is also essential to maintain a healthy and anti-inflammatory diet. There is no one specific diet for people with Hashimoto’s disease, but a low-iodine diet may prove helpful. (Source, Source, Source) Aloe, licorice, and foods high in Omega 3 may also help heal inflammation and improve gut health. (Source) The paleo, gluten-free, and autoimmune protocol (AIP) diets may help reduce inflammation and identify foods that trigger the immune response. (Source) 

Managing Hashimoto’s by protecting gut health

With all autoimmune diseases, the immune system attacks its own tissues. Hashimoto’s flare-ups are likely initiated by an overzealous immune response causing inflammation in the thyroid. For many patients, these autoimmune flares are linked to poor gut health or part of the gut-thyroid connection. (Source, Source, Source, Source)

Thus, improving gut health may reduce inflammation, frequency and severity of flare-ups, and thyroid autoimmunity. Research has shown that treating gut infections, such as H. pylori, can decrease thyroid peroxidase (TPO) antibodies, which are markers of thyroid autoimmunity, and improve thyroid-stimulating hormone (TSH) levels. (Source) 

Managing Hashimoto’s with probiotics

Probiotics can also help balance the gut microbiome, eliminate harmful microorganisms, promote a healthy immune response, and reduce inflammation. (Source) Probiotic supplements have been found to reduce the need for thyroid medications and decrease fatigue in people with Hashimoto’s. (Source)

Managing Hashimoto’s with dietary supplements

Vitamin D, whether through supplementation or safe sun exposure, may improve thyroid health and lower thyroid antibodies. (Source, Source) Selenium can reduce TPO antibodies that damage thyroid tissue. (Source, Source, Source) 

Managing Hashimoto’s with lifestyle changes

Lifestyle changes can help individuals manage symptoms of Hashimoto’s. These include: 

• Creating a regular sleep schedule and sleeping more
• Exercising
• Minimizing mental, emotional, and physical stress (Source)
• Controlling blood sugar levels 
• Treating anxiety and depression (Source, Source) 

The Bottom Line on Hashimoto’s Flare-Ups

Hashimoto’s flare-ups may include both mental and physical symptoms, such as fatigue and muscle weakness or aches, and commonly last for a few days or weeks at a time. There is no one definitive cause of flare-ups but certain foods or stressors are believed to trigger them. 

While there is no one-size-fits-all treatment for Hashimoto’s thyroiditis, it may be possible to reduce symptoms with an anti-inflammatory diet, regular sleep schedule, lifestyle changes, and stress reduction. When Hashimoto’s causes a permanent decrease in thyroid function, the standard treatment is supplementation with levothyroxine, a synthetic thyroid hormone.