Conversely, goiter is often caused by — and a symptom of — hyperthyroidism in the United States, where iodized salt provides plenty of iodine.

Goiter can affect anyone at any age, especially in areas of the world where foods rich in iodine are in short supply. However, goiters are more common after the age of 40 and in women, who are more likely to have thyroid disorders. Other risk factors include family medical history, certain medication usage, pregnancy, and radiation exposure.

There might not be any symptoms if the goiter isn’t severe. The goiter may cause one or more of the following symptoms if it grows large enough, depending on the size:

• swelling or tightness in your neck
• difficulties breathing or swallowing
• coughing or wheezing
• hoarseness of voice

Symptoms

The degree of swelling and the severity of symptoms produced by the goiter depends on the individual.

Most goiters produce no symptoms. When symptoms do occur, the following are most common:

• throat symptoms of tightness, cough, and hoarseness
• trouble swallowing
• in severe cases, difficulty breathing, possibly with a high-pitch sound

Other symptoms may be present because of the underlying cause of the goiter, but they are not because of the goiter itself. For example, an overactive thyroid can cause symptoms such as:

• nervousness
• palpitations
• hyperactivity
• increased sweating
• heat hypersensitivity
• fatigue
• increased appetite
• hair loss
• weight loss

In cases where goiter is a result of hypothyroidism, the underactive thyroid can cause symptoms such as:

• cold intolerance
• constipation
• forgetfulness
• personality changes
• hair loss
• weight gain

Aside from the swelling itself, many people with goiter present no symptoms or signs at all.

Causes

Goiter can be caused by a number of different conditions:

Iodine deficiency:

Iodine deficiency is the major cause of goiter worldwide, but this is rarely a cause in more economically developed countries where iodine is routinely added to salt.

As iodine is less commonly found in plants, vegan diets may lack sufficient iodine. This is less of a problem for vegans who live in countries such as the United States that add iodine to salt.

Dietary iodine is found in:

• seafood
• plant food grown in iodine-rich soil
• cow’s milk

In some parts of the world, the prevalence of goiters can be as high as 80 percent, such as in the remote mountainous regions of southeast Asia, Latin America, and central Africa. In these places, daily intake of iodine can fall below 25 micrograms (mcg) per day, and children are often born with hypothyroidism.

The thyroid gland needs iodine to manufacture thyroid hormones, which regulate the metabolism.

Other causes

Less common causes of goiter include the following:

• Smoking: Thiocyanate in tobacco smoke interferes with iodine absorption.
• Hormonal changes: Pregnancy, puberty, and menopause can affect thyroid function.
• Thyroiditis: Inflammation caused by infection, for example, can lead to goiter.
• Lithium: This psychiatric drug can interfere with thyroid function.
• Overconsumption of iodine: Too much iodine can cause a goiter.
• Radiation therapy: This can trigger a swollen thyroid, particularly when administered to the neck.

Goiter diagnosis and treatment

Your doctor will feel your neck area and have you swallow during a routine physical exam. Blood tests will reveal the levels of thyroid hormone, TSH, and antibodies in your bloodstream. This will diagnose thyroid disorders that are often a cause of goiter. An ultrasound of the thyroid can check for swelling or nodules.

Goiter is usually treated only when it becomes severe enough to cause symptoms. You can take small doses of iodine if goiter is the result of iodine deficiency. Radioactive iodine can shrink the thyroid gland. Surgery will remove all or part of the gland. The treatments usually overlap because goiter is often a symptom of hyperthyroidism.

Goiters are often associated with highly treatable thyroid disorders, such as Graves’ disease. Although goiters aren’t usually a cause for concern, they can cause serious complications if they’re left untreated. These complications can include difficulty breathing and swallowing.