Written by Ada’s Medical Knowledge Team
Overview of the thyroid gland
The thyroid is a butterfly-shaped gland found in the lower neck, just beneath the Adam’s apple. The hormones this gland releases control the body’s growth and metabolism. They affect processes like heart rate, digestion and temperature. Thyroid hormones are also essential for healthy mental and physical development. 1 2
When the levels of thyroid hormone are too high, symptoms of hyperthyroidism (overactive thyroid) may present, such as increased heart rate, weight loss and anxiety. Conversely, when the levels are abnormally low, there may be symptoms of hypothyroidism (underactive thyroid), like fatigue, weight gain and depression.
What is thyroiditis?
Thyroiditis is a term for inflammation of the thyroid gland, a condition which causes the levels of thyroid hormone in the body to go beyond the normal range.
Thyroiditis can be caused by several clinical disorders that present in different ways and require different courses of treatment, ranging from medication to surgery. The most common types of thyroiditis include Hashimoto’s thyroiditis, postpartum thyroiditis and De Quervain’s thyroiditis.
Women are far more likely than men to experience thyroid problems. 3 Thyroiditis can be a serious condition, and requires management by a doctor.
What are the symptoms of thyroiditis?
The symptoms of thyroiditis depend on whether the levels of thyroid hormone in the blood are too high (hyperthyroidism or thyrotoxicosis) or too low (hypothyroidism).
Good to know: Some of the symptoms may occur in both hyper- and hypothyroidism. If you think that you might have signs of a thyroid disorder, try using the Ada app to find out more about your symptoms.
Symptoms of hyperthyroidism (thyrotoxicosis) include:
- Anxiety or nervousness
- Increased sweating
- Heat intolerance
- Weight loss or difficulty gaining weight, despite a good appetite
- Insomnia (sleeplessness or sleep disturbances)
- Racing heart or palpitations (pronounced awareness of one’s heartbeat) 4
- High blood pressure 5
- Increased frequency of bowel movements
- Nausea and vomiting 6
- Fatigue (generally feeling tired or weak)
- Tremors (shaky hands)
- Feeling of weakness in the muscles (particularly in the upper arms and thighs)
- Difficulty exercising
- Eye bulging and irritation
- Light or no menstruation
Symptoms of hypothyroidism include:
- Fatigue (generally feeling tired or weak)
- Sensitivity to cold
- Dry skin
- Poor exercise tolerance
- Unexplained weight gain
- Brittle nails
- Hair loss
- Tongue enlargement (swelling)
People affected by thyroiditis may present with a goiter – the medical term for an enlarged thyroid gland. There may be noticeable swelling in the lower part of the neck. Goiters can be related to hyper or hypothyroidism, as well as thyroid nodules and a number of other conditions that affect the thyroid.
Thyroid goiters are usually painless, but can cause a tight feeling in the throat, hoarseness, coughing, and difficulty swallowing and breathing (if they are very large). A goiter does not necessarily indicate that thyroid function has been compromised, and small thyroid goiters may not require medical treatment. 15
Types of thyroiditis
There are a number of different types of thyroiditis. Many of these thyroid problems seem to run in families, and they tend to affect a higher number of women than men. 3
Hashimoto’s thyroiditis (Hashimoto’s disease)
Also known as chronic lymphocytic thyroiditis, Hashimoto’s thyroiditis or disease - sometimes written as Hashimoto thyroiditis - is the most common type of thyroiditis. It is an autoimmune condition in which the immune system mistakenly attacks the thyroid gland, causing inflammation and gradual damage that can lead to hypothyroidism over time. Hashimoto’s thyroiditis is more prevalent among women than men, and is commonly associated with a family history of thyroid disease. 16
Hashimoto’s thyroiditis tends to progress slowly and can take months or even years to be detected. 1 Those affected may present with a painless goiter, symptoms of hypothyroidism and high levels of thyroid antibodies. Though less common, there may also be symptoms of hyperthyroidism. In some cases, the disease may begin with a period of hyperthyroidism, which leads to hypothyroidism as the thyroid gland becomes damaged. The hypothyroidism, which is often lifelong, is treated with thyroid hormone replacement. Sometimes, periods of thyroid over- and underactivity may alternate over the course of the disease. Regular monitoring and blood tests can help a person manage any thyroid hormone fluctuations that occur. 16
Hashimoto’s thyroiditis is sometimes associated with other autoimmune conditions, including Addison’s disease, type 1 diabetes, pernicious anemia, celiac disease and connective tissue disorders like rheumatoid arthritis. For more information, see the dedicated page on Hashimoto’s thyroiditis.
Also known as Ord’s disease, this autoimmune condition is characterized by atrophy of the thyroid gland and hypothyroidism. It is very similar to Hashimoto’s disease, apart from the shrinking of the thyroid gland instead of the development of a goiter. Ord’s disease and Hashimoto’s disease have historically been classified as separate disorders, but research suggests that they may instead be different manifestations of autoimmune thyroiditis, with some medical practitioners calling for the combined term Ord-Hashimoto’s disease to be used. 17
Also known as painless thyroiditis or subacute lymphocytic thyroiditis, this is an autoimmune disease (autoimmune meaning that the immune system attacks healthy cells) that presents with an initial period of hyperthyroidism (three months or less), followed by temporary hypothyroidism.
Silent thyroiditis generally resolves on its own within 12-18 months, 1 though in some cases the hypothyroidism may occasionally be permanent. Treatment may include beta-blockers to relieve the symptoms of hyperthyroidism and thyroid hormone replacement, when necessary, in the hypothyroid phase.
Sometimes classified as a type of silent thyroiditis, postpartum thyroiditis is a type of thyroiditis after pregnancy that affects people who have recently (within the last 12 months) given birth, or had a miscarriage, or medical abortion. 18 The condition is autoimmune in nature and typically manifests with an initial period of hyperthyroidism, followed by hypothyroidism that may be temporary or permanent. Not all people experience both phases. 1 Postpartum thyroiditis most often affects people with a prior history of thyroid dysfunction, and resembles Hashimoto’s thyroiditis – as does regular silent thyroiditis. They are considered variants of Hashimoto’s thyroiditis. 19
Some medications may cause hypothyroidism or, more rarely, hyperthyroidism. Treatment with lithium is known to cause hypothyroidism in 5-15 percent of people and goiter in up to 37 percent. 20 Iodine and iodine-containing medications, such as amiodarone, interleukin-2 (IL-2) or interferon, can also affect thyroid function. 21 Drugs used to treat hyperthyroidism can result in a hypothyroid state, and vice versa, if dosages are incorrect for a particular person. Treatment requires management of medications and dosages with a doctor.
Sometimes also called Riedel’s struma or invasive fibrous thyroiditis, this is an extremely rare type of thyroiditis. The cause is unclear, though it is thought to be either an autoimmune or primary fibrotic (referring to an excessive build-up of connective tissue) disorder. Riedel’s thyroiditis typically presents with a hard, painless mass in the front of the neck. As the disease progresses, affected people may experience hoarseness, difficulty swallowing and breathing, as well as choking. There may also be hypothyroidism and hypoparathyroidism. Treatment may involve corticosteroids, thyroid hormone replacement and surgery. 22 23
De Quervain’s thyroiditis (subacute thyroiditis)
Also known as painful subacute thyroiditis, subacute nonsuppurative thyroiditis, giant cell thyroiditis and subacute granulomatous thyroiditis, this is a relatively rare condition that mostly affects middle-aged women who have recently had a viral infection of the upper respiratory tract. Overall, De Quervain’s thyroiditis is the most common cause of a painful thyroid gland.
The main symptoms of De Quervain’s thyroiditis are fever, pain in the throat and thyroid region of the neck (which may radiate to the jaw and ears) and an enlarged thyroid gland. Initially, a person with De Quervain’s may present with symptoms of hyperthyroidism, as the condition causes the release of high levels of thyroid hormone. This is sometimes followed by a temporary (transient) phase of hypothyroidism.
De Quervain’s thyroiditis is usually self-limiting, with the condition clearing on its own within a few months. Treatment is aimed at minimizing pain and discomfort, and aspirin or another NSAID (Nonsteroidal Anti-Inflammatory Drug), such as ibuprofen may be recommended. In severe cases, a corticosteroid may be prescribed as a potent anti-inflammatory measure. A beta-blocker may be given to ease some of the symptoms of hyperthyroidism, like a racing heart, high blood pressure, feeling agitated or having tremors. Antithyroid medication is not usually necessary. The temporary hypothyroidism that is often the last stage of the condition, before patients recover, may necessitate short-term treatment with thyroid hormone replacement.
Thyroid function generally returns to normal (a euthyroid state), though in a few cases De Quervain’s can recur and result in permanent hypothyroidism. 24
A number of people who undergo radioactive iodine therapy for hyperthyroidism, develop radiation-induced thyroiditis after the procedure. Radiation therapy for certain cancers, such as lymphoma, head and neck cancers, can also trigger thyroiditis. 25 Those affected may present with symptoms of hyper or hypothyroidism, ref1 as well as tenderness in the thyroid area. Treatment may involve beta-blockers to alleviate symptoms of temporary (transient) hyperthyroidism, painkillers ref17 and thyroid hormone replacement where necessary. 26
Acute infectious thyroiditis
This very rare type of thyroiditis, also known as suppurative thyroiditis or acute thyroiditis (to be distinguished from subacute thyroiditis), is caused by an infection of the thyroid gland with bacteria or other microbes. The disease is associated with a weakened immune system that may be caused by any number of reasons or, in the case of children, an abnormality in the development of the thyroid gland. 1 Most people affected by acute infectious thyroiditis have a pre-existing thyroid disorder such as Hashimoto's thyroiditis or thyroid cancer. 27
Symptoms include pain in the front of the neck, soreness in the throat, fever and a rapid heart rate. Thyroid hormone levels tend to be within the normal range. The cause of infection is typically determined using fine-needle aspiration (a type of biopsy), after which a treatment option will be prescribed. Most likely, this will require antibiotics or other antimicrobial agents and, in the case of an abscess, surgical drainage. Without effective and timely treatment, the condition can potentially be life-threatening. 28
Diagnosis of thyroiditis (thyroid tests)
A number of diagnostic methods may be used to confirm that thyroiditis or another thyroid condition is present, including blood tests and ultrasound scans.
- TSH (thyroid stimulating hormone)
- FT4 (free thyroxine)
- FT3 (free triiodothyronine) – only occasionally
The amount of thyroxine (the thyroid’s main hormone) secreted by the thyroid gland is regulated by the pituitary gland (also called the hypophysis, a small hormone gland located at the base of the brain). The pituitary gland secretes TSH according to the amount of T4 (thyroxine) that is needed. T4 is converted into T3 (triiodothyronine), which is the biologically active form of thyroid hormone. 29
If the level of TSH is high and the FT4 low in a thyroid blood test, it indicates hypothyroidism. Conversely, if the level of TSH is low and the FT4 high, hyperthyroidism is indicated. The ranges used vary slightly by country and lab. 29
Where the TSH level is slightly elevated, but the FT4 level is normal, subclinical or mild hypothyroidism is indicated. Because this may progress to full-blown hypothyroidism, follow-up tests may be recommended. 29
When autoimmune thyroiditis is suspected, a doctor may order further blood tests to see whether thyroid antibodies are present at levels above the reference range. These include thyroid peroxidase antibodies (TPOAb) and thyroglobulin antibodies (TgAb) to confirm Hashimoto’s thyroiditis, and thyroid stimulating hormone receptor antibodies (TSHR Ab), which are also called TSH receptor antibodies (TRAbs), in the case of Graves’ disease. 29
This non-invasive test may be ordered to check the thyroid gland for swelling and nodules, and blood circulation pattern. An ultrasound is also used to check the parathyroid glands (four glands that are situated on the back of the thyroid and produce parathyroid hormone, which affects the body’s calcium metabolism). 30
Radioactive iodine uptake test
In some cases (particularly when hyperthyroidism is present), a radioactive iodine uptake test may be recommended – often together with a thyroid scan (a specialized imaging procedure). In both of these tests, a small amount of a weak radioactive substance is administered. 31A radioactive iodine uptake test allows the medical practitioner to determine whether the thyroid gland, which naturally takes up iodine, 32 is functioning normally, and why thyroid hormone levels may be out of range. A scan can detect thyroid nodules and inflammation. ref20
Fine needle aspiration
If a suspicious thyroid nodule is detected, a fine needle aspiration biopsy may be performed to determine whether it is benign (non-cancerous) or malignant (cancerous). 33
Treatment depends on the type of thyroiditis, as well as its progression. Pain and inflammation caused by thyroiditis may be treated with aspirin, ibuprofen or other anti-inflammatory painkillers (NSAIDs), with the addition of corticosteroids where necessary.
An underactive thyroid is treated with thyroid hormone replacement. This usually takes the form of levothyroxine (a synthetic/lab-created form of T4), with the dosage determined by the severity of the hypothyroidism, as well as the weight and age of the affected person. Regular thyroid blood tests are necessary to ensure that the levels of thyroid hormone do not become too high (thyrotoxicosis) 34 or remain too low. 35
An overactive thyroid can be treated in a number of ways. There is no single preferred method – the chosen option usually depends on the type and severity of hyperthyroidism, as well as the age and general health of the affected person.
Treatment methods include antithyroid drugs like methimazole, which block the ability of the thyroid gland to produce thyroid hormone, radioactive iodine, which destroys the thyroid cells that produce thyroid hormone and thyroid surgery (thyroidectomy), where most of the thyroid gland is removed, and the resultant hypothyroidism is treated with levothyroxine. Beta-blockers may be prescribed to lessen the symptoms of hyperthyroidism, mainly fast heart rate and high blood pressure, while treatments are taking effect. 7
Because treatment will depend on the type of thyroiditis experienced, consultation with a medical professional is very important. Taking over-the-counter medication without advice from a healthcare provider is not recommended.
Other thyroid conditions
Also known as diffuse toxic goiter and Basedow’s disease, Graves’ disease is an autoimmune condition in which the thyroid gland is stimulated to produce too much thyroid hormone, causing hyperthyroidism or thyrotoxicosis. Like Hashimoto’s disease, it seems to have a genetic component and is more prevalent among women than men. Graves’ disease is one of the most common causes of hyperthyroidism. 34
People affected by Graves’ disease may present with painless enlargement of the thyroid gland, symptoms of hyperthyroidism and high levels of thyroid antibodies. In addition, there may be symptoms of Graves’ ophthalmopathy, where the eyes are affected by a gritty sensation, pain or pressure. There may also be swollen eyelids, light sensitivity, double vision or bulging eyes, among other symptoms. Graves’ ophthalmopathy is seen in approximately 30 percent of people affected by Graves’ disease. There may also be reddening and thickening of the skin, most often on the shins or tops of the feet. This is called Graves’ dermopathy 36 or pretibial myxedema, 37 and is rare.
The hyperthyroidism is treated with antithyroid medication, radioactive iodine or thyroid surgery. Where permanent hypothyroidism results, levothyroxine is prescribed to replace the thyroid hormone and is typically taken for life. 34
Thyroid nodules are lumps in the thyroid gland. They may be solid or filled with fluid. Nodules may be too small to detect without a physical examination, thyroid ultrasound or thyroid scan, or large enough that they are visible and, in rare cases, even obstruct breathing or swallowing. 38
The majority of thyroid nodules do not cause any symptoms. However, some produce extra thyroxine, which can cause symptoms of hyperthyroidism as thyroid hormone levels go out of range.
Thyroid nodules may be associated with iodine deficiency (rare in the United States, more common in many regions of Europe), overgrowth of normal thyroid tissue (thyroid adenomas) or Hashimoto’s disease, among other conditions. 39 40
A thyroid nodule may also be a sign of thyroid cancer. However, most thyroid nodules are benign (non-cancerous growths). It is estimated that only two to three out of 20 thyroid nodules are cancerous. 41
If a thyroid nodule is non-cancerous (benign) and not causing any symptoms, treatment may not be necessary. A doctor may simply opt to perform regular examinations and thyroid function tests to monitor its progress. Large nodules, and those that cause symptoms, may be removed surgically or treated with radioactive iodine (if they are producing thyroxine). 42
Thyroid cancer is relatively rare, but rates seem to be increasing. It is thought that this is due to advances in technology which allow medical practitioners to detect small thyroid cancers that may previously have gone unnoticed. Most cases of thyroid cancer are treatable and can be cured, allowing those affected to live a normal life. 43 44
Early symptoms of thyroid cancer are rarely noticeable. However, in some cases, firm, painless nodules may be noted. Later symptoms may include rapid growth of a goiter, throat hoarseness or pain that does not go away, difficulty swallowing or breathing, pain in the front of the neck and an unexplained cough. 44 45 46
There are four main types of thyroid cancer:
- Papillary (the most common type)
- Follicular (the second most common type)
- Medullary (rare, may run in families)
- Anaplastic (rare, an aggressive type of thyroid cancer)
Treatment depends on the type of thyroid cancer and may involve full (or, in rare cases, partial) removal of the thyroid gland during thyroid surgery, radioactive iodine therapy, radiotherapy and chemotherapy. Levothyroxine is prescribed to prevent hypothyroidism after treatment, and is taken for life. 44
Q: Is there a special thyroid diet?
A: There is no specific thyroid diet that is recommended for people affected by thyroid disorders. A healthy, balanced diet is generally sufficient. It is not advisable to take special supplements, including iodine preparations, without first consulting a doctor.
Some foods and supplements can, however, interfere with the absorption of levothyroxine, so those taking this medication should keep in mind the following:
- After taking calcium-rich foods or supplements, wait four hours before taking levothyroxine
- After taking iron tablets, wait two hours before taking levothyroxine
- Wait as long as possible after taking levothyroxine before eating soya or soy products
In addition, kelp and iodine supplements should be avoided unless otherwise recommended by a healthcare provider, as they can potentially aggravate thyroid disorders. A healthy, varied diet usually provides sufficient amounts of iodine. In many countries, where the normal diet contains too little iodine, table salt is iodized, meaning it has iodine added to it, to help prevent iodine deficiency from occurring.
Vegetables of the Brassica family, such as cabbage, broccoli and kale, may be implicated in the development of a goiter in some people, but only in very rare cases where consumption is extremely high. It is not a problem under normal dietary conditions. 47
Q: What is thyroid hair loss?
A: This is the phrase used to describe the loss of hair that may occur in severe, prolonged hypothyroidism or hyperthyroidism. The hair loss tends to affect the entire scalp, as opposed to small areas, and the hair may appear sparse. There may also be loss of eyebrow hair. Thyroid hair loss is unusual in mild thyroid disorders.
The hair typically grows back once the thyroid disorder has been successfully treated. However, this may take a few months, and regrowth is not always complete. 48 Partial hair loss is listed as a possibility during the first few months of treatment with levothyroxine. 49 In rare cases, antithyroid drugs may also be associated with hair loss. ref36
Q: What precautions need to be taken with the thyroid in pregnancy?
A: Normal levels of thyroid hormone in an expectant mother are essential for the healthy development of the baby. People with pre-existing thyroid conditions may need to adjust the dosage of their medication during pregnancy, with regular thyroid function tests to ensure that their thyroid hormone levels are within the optimal range.
In some parts of the world, such as Germany, pregnant women may be encouraged to take iodine supplements to compensate for deficiencies in the soil and the lack of fortification of food products. A doctor will be able to advise on whether supplementation is necessary.
People who develop symptoms of hyperthyroidism or hypothyroidism while pregnant need to seek immediate medical care. If symptoms of postpartum thyroiditis are present after the delivery of the baby, the mother should consult with a doctor. Postpartum thyroiditis may be mistaken for postpartum depression. 8
Q: Can thyroiditis cause cancer?
A: While thyroiditis itself does not cause cancer, some types of thyroiditis, e.g. Hashimoto’s disease, may be associated with an increase in a person’s risk of developing thyroid cancer and certain other types of cancer. 50 51 It is advisable to speak to a doctor about any cancer concerns you may have.
Q: Can thyroiditis recur?
A: Yes, thyroiditis can come back or return, meaning that the condition can occur more than once. A person may also experience repeat episodes of hypothyroidism or hyperthyroidism as a result of some types of thyroiditis.
Q: Can thyroiditis cause a sore throat?
A: Yes, a sore throat can be a sign of some types of thyroiditis, such as subacute thyroiditis and Hashimoto’s thyroiditis. See the dedicated sections above for more information. 52 53
Q: Can thyroiditis cause swollen lymph nodes?
A: Swollen lymph nodes in the neck can be a sign of thyroiditis that is autoimmune in nature, e.g. Hashimoto’s thyroiditis, as well as in acute infectious thyroiditis. However, swollen lymph glands can also be a sign of many other conditions. If you have swollen lymph nodes and other signs of a thyroid problem, it is advisable to consult a doctor. 54 55
Q: Can a thyroid nodule cause weight gain?
A: Most thyroid nodules themselves do not affect a person’s weight. However, a thyroid nodule can be associated with Hashimoto’s disease, which is a thyroid condition that can lead to weight gain and other symptoms of hypothyroidism.
Q: Do I have thyroiditis?
A: If you think that you might have thyroiditis, try using the Ada app to find out more about your symptoms, and consult a doctor.