A goitre (sometimes spelt goiter) is an abnormal swelling of the thyroid gland that causes a lump to form in the neck.

There can be many possible causes, including an under- or overactive thyroid gland, iodine deficiency and, rarely, thyroid cancer (see below).

The thyroid gland

The thyroid gland is a small butterfly-shaped gland in the neck, just in front of the windpipe (trachea). It produces thyroid hormones, which help regulate the body’s metabolism (the chemical processes that occur in the body).

The thyroid gland isn’t usually noticeable, but if it swells, it produces a lump on the neck known as a goitre.

The size of a goitre can vary from person to person. In most cases, the swelling is small and doesn’t cause any symptoms. However, in more severe cases, the swelling can increase significantly and affect breathing and swallowing.

Read more about the symptoms of a goitre.

What causes a goitre?

Goitres can have several possible causes, including:

Read more about the causes of a goitre.

Diagnosing a goitre

If you think you have a goitre, see your GP – they can carry out some tests to determine whether you have one.

Your GP will examine your neck to see whether your thyroid gland is swollen. They may also refer you for a thyroid function test, to see how well your thyroid gland is working.

A thyroid function test measures the level of certain hormones (chemicals produced by the body) in your blood. It can show whether you have an underactive or overactive thyroid, both of which are associated with goitre.

Read more about how a goitre is diagnosed.

Treating a goitre

The treatment for goitres depends on the underlying cause. If the goitre is small and isn’t causing any problems, a wait-and-see approach is usually recommended.

Other possible treatments include radioiodine treatment and thyroid surgery.

Although most goitres are usually benign (non-cancerous), it’s estimated that in 1 in 20 cases they may be a sign of thyroid cancer.

Read more about treating a goitre.

Thyroid gland
The thyroid gland is found in the neck. It produces hormones that are released into the bloodstream to control the body’s growth and metabolism (the process that turns food into energy).

Symptoms of goitre

The main symptom of a goitre is swelling of the thyroid gland, which causes a lump to develop in the front of the neck.

The lump will move up and down when you swallow.

Types of goitre

There are two main types of goitre:

  • diffuse goitre  where the entire thyroid gland swells and feels smooth to the touch
  • nodular goitre  where solid or fluid-filled lumps called nodules develop within the thyroid and make the thyroid gland feel lumpy to touch; the nodules can be single or multiple

Other symptoms

Other associated symptoms can include:

  • coughing 
  • a tight feeling in your throat
  • changes to your voice, such as hoarseness

Less commonly, you may also have: 

  • difficulty swallowing (dysphagia)
  • difficulty breathing  there may be a high-pitched sound when you breathe (stridor)
Hormones are groups of powerful chemicals that are produced by the body and have a wide range of effects.
A nodule is a small growth or lump of tissue.
Thyroid gland
The thyroid gland is found in the neck. It produces hormones that are released into the bloodstream to control the body’s growth and metabolism (the process that turns food into energy).

Causes of goitre

Goitres can have many possible causes. Sometimes, a cause can’t be identified.

Iodine deficiency

Iodine deficiency used to be the primary cause of goitre, but dietary changes mean it’s now rare in the UK. However, it remains a significant problem in parts of the developing world.

Iodine is a trace element found in seawater and soil. It enters the food chain through plants that grow in iodine-rich soil, or through fish or plants from the sea. Iodine is found in:

  • seafood, such as fish, shellfish or seaweed
  • plant foods, such as cereals or grains
  • cow’s milk

The thyroid gland (a gland in the neck that produces hormones) needs iodine to help manufacture thyroid hormones (chemicals released into the bloodstream that control the body’s growth and metabolism).

If your body doesn’t receive enough iodine, your thyroid gland becomes underactive and increases in size, in order to produce more thyroid hormones.

Until the early 1900s, iodine deficiency used to be a common problem in the UK. Around this time, salt manufacturers started adding small amounts of iodine to salt, which reduced the number of cases.

However, in recent years, the number of people experiencing iodine deficiency in the UK has started to rise. This could be due to an increased preference for a low-salt, non-dairy diet. Iodine deficiency can be a problem for people who follow a strict vegan diet (where meat, eggs, dairy foods and all other animal-derived products are excluded).

Overactive thyroid gland

A goitre can develop if the thyroid gland becomes overactive (hyperthyroidism), resulting in too much thyroid hormone being produced. Increased hormone production over-stimulates the thyroid gland and causes it to swell.

The leading cause of hyperthyroidism is a condition called Graves’ disease. This causes your immune system (the body’s natural defence system) to send antibodies (proteins that fight infections) to your thyroid gland. The antibodies stimulate the thyroid gland, causing an increased amount of thyroid hormones to be released.

Underactive thyroid gland

A goitre can also develop if the thyroid gland becomes underactive (hypothyroidism). If the thyroid gland doesn’t produce enough thyroid hormones, your body will stimulate it to produce more. This can cause the thyroid gland to swell.

As well as iodine deficiency, one of the leading causes of hypothyroidism is a condition called Hashimoto’s thyroiditis, which is sometimes known as Hashimoto’s disease.

As with Graves’ disease, Hashimoto’s thyroiditis is an autoimmune condition. However, rather than over-stimulating the gland, it causes inflammation within the thyroid gland and interferes with its ability to produce hormones. To compensate for this, the body causes the gland to swell, resulting in a goitre.


There may also be a link between smoking and an increased risk of developing a goitre. This may be because tobacco smoke contains a chemical called thiocyanate, which can interfere with the body’s ability to utilise iodine.

People who smoke and have a low-iodine diet are particularly at risk. Read more about how to stop smoking.

Other causes

Many other causes have been linked to goitres, which are outlined below.

Pregnancy, the menopause and puberty

The changes in hormone levels that occur during pregnancy, the menopause and puberty (sexual maturation) can affect the thyroid gland.


Lithium is a medicine that’s often used to treat a number of mental health conditions, such as depression and bipolar disorder (a condition that affects your moods, which can swing from one extreme to another). Lithium can interfere with how your thyroid gland functions.


The thyroid gland can become inflamed. This condition is known as thyroiditis, and it can sometimes occur after pregnancy, as a result of certain viral and bacterial infections, or after taking certain medications. Thyroiditis can cause a painful goitre to develop.     

Excessive iodine

Too much iodine can build up in the body as a result of eating too much iodine-rich food. Seaweed, for example, particularly kelp, is a rich source of iodine. Having too much in the body can affect the thyroid gland.

Radiation exposure

Radiation exposure can sometimes cause goitres. Radiation, in the form of radiotherapy, is often used to treat certain health conditions, such as cancer. Having radiotherapy to the neck can sometimes cause goitres.

Nodules within the thyroid

Single or multiple nodules within the thyroid gland can cause goitres. Most thyroid nodules are benign (non-cancerous), but all nodules need to be assessed thoroughly to exclude thyroid cancer (see below).

Thyroid cancer

Thyroid cancer is another possible cause of goitres, although it’s rare in the UK. Cancer Research UK estimates that less than 1 in every 100 cancers diagnosed in the UK is thyroid cancer.

Read more about thyroid cancer.

An antibody is a protein that is produced by the body to neutralise or destroy disease-carrying organisms and toxins.
Hormones are groups of powerful chemicals that are produced by the body and have a wide range of effects.
Immune system
The immune system is the body’s defence system, which helps protect it from disease, bacteria and viruses.
Thyroid gland
The thyroid gland is found in the neck. It produces hormones that are released into the bloodstream to control the body’s growth and metabolism (the process that turns food into energy).

Diagnosing goitre

If you think you have a goitre, see your GP. They can examine your neck to see if there’s any evidence of thyroid gland swelling.

Blood tests to check how well your thyroid gland is working may also be carried out.

Physical examination

Your GP will examine your neck to assess the size and extent of any swelling and determine whether it’s:

  • a diffuse goitre  where your entire thyroid gland swells up and feels smooth
  • a nodular goitre  where solid or fluid-filled nodules develop within the thyroid, making the thyroid gland feel lumpy

They may ask you to swallow, to see whether the lump moves up and down.

Your GP may also arrange for you to have a thyroid function test to determine the underlying cause of your goitre.

Thyroid function test

A thyroid function test measures the level of certain hormones (chemicals produced by the body) in your blood.

The test can show if you have an underactive or overactive thyroid gland, both of which are associated with goitre.

The thyroid gland produces two hormones – thyroxine and triiodothyronine. An excessive amount of these two hormones indicates an underlying condition that’s making your thyroid gland overactive, such as Graves’ disease (an autoimmune condition that causes antibodies to stimulate the thyroid gland).

If your thyroid gland is underactive, your pituitary gland (a pea-sized gland that sits below the brain) will produce a hormone called thyroid stimulating hormone (TSH).

TSH is released by your body to stimulate your thyroid gland. A high level of TSH in your blood indicates that your thyroid gland is underactive.

Further tests

If you’re referred to a specialist, you may have further tests in hospital. These are described in more detail below.

Radioactive iodine scan

This involves a small amount of radioactive iodine being injected into your vein. The iodine builds up in your thyroid gland, which can then be studied using a special camera.

The scan can provide useful information about the structure and function of your thyroid gland. As the amount of radiation used is very small, it’s perfectly safe for most people. However,it may not be suitable if you’re pregnant.

Ultrasound scan

An ultrasound scan uses high-frequency sound waves to create an image of part of the inside of your body. It can be used to:

  • build up a picture of the inside of your thyroid gland
  • assess the size of your thyroid gland
  • check whether there are any enlarged nodules in your thyroid gland not found during the physical examination

Fine-needle aspiration

Fine-needle aspiration is a procedure where a sample of the goitre is extracted, so that the cells inside it can be tested. This procedure is often known as a biopsy

During the procedure, a fine needle on the end of a syringe will be inserted into the goitre in your throat. A sample of the fluid or tissue inside the goitre will be sucked through the needle and into the syringe. The sample will be examined under a microscope to determine what kind of cells are inside the goitre. 

Autoimmune condition
An autoimmune condition is when your immune system (the body’s defence system) produces antibodies (proteins) that should fight infections, but instead attack your body’s healthy tissues.
Hormones are groups of powerful chemicals produced by the body and have a wide range of effects.
Thyroid gland
The thyroid gland is found in the neck. It produces hormones that are released into the bloodstream to control the body’s growth and metabolism (the process that turns food into energy).

Treating goitre

Treatment for goitre can include medication, hormone therapy and surgery.

The treatment you receive will depend on:

  • the size of the goitre
  • the symptoms the goitre is causing
  • whether you have any underlying conditions, such as an overactive thyroid gland (hyperthyroidism) or an underactive thyroid gland (hypothyroidism)

If tests reveal your thyroid gland is working normally, and the goitre is small, no immediate treatment may be necessary and your condition may just be monitored.

If you have a problem with your thyroid gland, however, it will be treated. Surgery may be needed if your condition doesn’t improve with treatment. A study has estimated that up to one in seven people with goitres may eventually require surgery. 

Underactive thyroid gland

If tests reveal that you have an underactive thyroid gland, treatment could include using a synthetic hormone to replicate your normal thyroid function (hormone therapy).

The synthetic hormone is levothyroxine and is taken orally, usually once a day.

Side effects of levothyroxine, which usually occur when too much has been taken, can include:

These side effects should pass in a few days as your body gets used to the hormone. However, if they continue, speak to your GP as your dosage may need to be adjusted. In most cases, hormone therapy will need to be carried out for the rest of your life.

Read more about treating hypothyroidism.

Overactive thyroid gland

If you have an overactive thyroid gland, there are several recommended treatments. Some are described below.


Thionamides are a type of medication that help reduce the amount of hormones your thyroid gland is producing.

Thionamides are usually taken orally. They work by gradually reducing levels of thyroid hormones, so it may be several weeks before you notice any effects.

Side effects of thionamides include:

  • a mild skin rash
  • joint pain
  • nausea (feeling sick)
  • itchy skin

In very rare cases, thionamides can cause a serious condition called a sudden drop in the number of white blood cells (agranulocytosis). This usually occurs within the first three months of treatment.

Signs to look out for include:

If you notice any of the above, see your GP.

You may need to take thionamides for two to four months before the overactive thyroid gland is controlled.

Radioactive iodine

Radioactive iodine is another treatment for an overactive thyroid gland that’s taken orally. When the iodine reaches your thyroid gland, it destroys the thyroid cells and reduces the goitre’s size.

However, the treatment may cause your thyroid gland to become underactive. If this happens, you may need hormone therapy (see above).

Read more about treating hyperthyroidism.

Iodine supplements

well-balanced diet usually provides all the iodine your body needs, and iodine supplements aren’t usually required in developed countries like the UK. Your GP can give more advice about extra supplements, if needed.

Iodine supplements are available in many health food shops without a prescription. However, always consult your GP before taking them, because the amount of iodine needed varies from person to person. Taking too much iodine may cause other health problems, and it could also have toxic (poisonous) effects.


If your goitre is interfering with your breathing or swallowing, and it hasn’t responded to other forms of treatment, you may need surgery to remove part or all of your thyroid gland. This procedure is known as a thyroidectomy.

You will be given a general anaesthetic, meaning you will be unconscious and unable to feel anything. 

During surgery, the surgeon will make an incision in the front of your neck so they can see your thyroid gland.

How much of the thyroid gland is removed will depend on the underlying condition causing the goitre. The procedure will reduce the size of your goitre and the amount of thyroid hormones being produced.

The surgeon will attempt to remove enough of your thyroid gland to relieve your symptoms, while leaving enough so that normal thyroid hormone production can continue. However,  if this isn’t possible, you may require hormone therapy after surgery.

Surgery to remove the thyroid gland is usually safe, but as with all surgical procedures there’s a risk of complications, such as post-operative infection.

The risks of complications occurring after thyroid gland surgery are estimated to be 1-2%. Before having the procedure, you should discuss the risks with your surgeon.

Nerve damage and parathyroid gland damage are two other possible complications of thyroid gland surgery. These are briefly described below.

Nerve damage

The thyroid gland is very close to the two laryngeal nerves, which control your vocal cords. If these are accidentally damaged during surgery, your voice and breathing could be affected.

Permanent damage to the laryngeal nerves affects one to two people in every 100 who have this type of surgery. Temporary damage may affect up to five people in every 100.

Parathyroid gland damage

The parathyroid glands help regulate the amount of calcium in your body. If the parathyroid glands are damaged, you will probably need to take calcium supplements for the rest of your life.

Hormones are groups of powerful chemicals that are produced by the body and have a wide range of effects.
An incision is a cut made in the body with a surgical instrument during an operation.
Thyroid gland
The thyroid gland is found in the neck. It produces hormones that are released into the bloodstream to control the body’s growth and metabolism (the process that turns food into energy).
White blood cells
White blood cells are the part of blood that fight infection and disease.