A goiter is an enlargement of the thyroid gland, the butterfly-shaped gland at the base of your neck that controls metabolism, energy, and hormone production. Goiters range from barely noticeable swelling to large growths visible from across a room. Some cause no symptoms at all, while others press on nearby structures and interfere with swallowing or breathing. The most common cause worldwide is iodine deficiency, affecting an estimated 2.2 billion people globally.
Types of Goiter
Goiters are classified in two ways: by their shape and by whether they affect thyroid hormone levels.
Based on shape, there are three main types. A diffuse goiter means the entire thyroid swells evenly and feels smooth. A nodular goiter develops when a solid or fluid-filled lump forms inside the gland, making it feel bumpy. A multinodular goiter contains multiple lumps, which may be visible on the neck or only detectable through imaging.
Based on hormone activity, a goiter is either toxic or nontoxic. A toxic goiter produces too much thyroid hormone, pushing the body into a state of hyperthyroidism with symptoms like rapid heartbeat, weight loss, and anxiety. A nontoxic goiter is enlarged but still produces normal hormone levels, meaning the thyroid itself is functioning fine despite its larger size. Some goiters also develop alongside an underactive thyroid, where hormone levels drop too low.
What Causes a Goiter
Iodine deficiency is the leading cause of goiters worldwide. Your thyroid needs iodine to manufacture its hormones. When iodine intake is too low, the gland works harder and grows larger in an attempt to compensate. This is most common in regions without iodized salt programs. Central Sub-Saharan Africa and South Asia have the highest rates of iodine deficiency, with countries like Somalia and the Democratic Republic of the Congo reporting the most severe burdens.
In countries where iodized salt is standard (including the United States and most of Europe), autoimmune diseases are the primary culprits. Hashimoto’s thyroiditis, where the immune system attacks the thyroid, causes the gland to enlarge gradually over months or years and typically leads to an underactive thyroid. Graves’ disease, another autoimmune condition, stimulates the thyroid to overproduce hormones, resulting in a diffuse toxic goiter.
Certain medications can also trigger goiter formation. Lithium, commonly prescribed for bipolar disorder, can interfere with thyroid hormone production and lead to both hypothyroidism and gland enlargement. Other substances known as goitrogens, found naturally in foods like raw cruciferous vegetables or introduced through environmental chemicals, can have a similar blocking effect. In these cases, the thyroid grows as it tries to restore normal hormone output.
Symptoms to Recognize
Small goiters often cause no symptoms and are discovered during a routine physical exam or imaging done for another reason. As the gland grows, though, it can produce noticeable effects simply because of where it sits in the neck, surrounded by the windpipe, esophagus, and vocal cord nerves.
The most common symptoms include:
- Visible swelling at the base of the neck, sometimes more obvious when you swallow
- Difficulty swallowing as the enlarged gland presses against the esophagus
- Breathing trouble if the goiter compresses the windpipe, particularly when lying down
- Hoarseness or voice changes from pressure on the nerves that control the vocal cords
- A tight feeling in the throat or neck
If the goiter extends downward behind the breastbone (called a retrosternal goiter), it’s more likely to compress the airway. Noticeable changes in breathing typically don’t occur until the airway’s cross-sectional area has been reduced by more than 50%, so significant compression can build gradually before symptoms become obvious.
When a goiter is toxic, you’ll also experience symptoms of excess thyroid hormone: unintentional weight loss, heat intolerance, trembling hands, irritability, and a racing pulse. When it’s linked to an underactive thyroid, expect fatigue, weight gain, cold sensitivity, and sluggishness.
How a Goiter Is Diagnosed
Diagnosis typically starts with a blood test measuring TSH, the hormone your pituitary gland sends to tell the thyroid how hard to work. A high TSH suggests the thyroid is underperforming, pointing toward conditions like Hashimoto’s thyroiditis or a medication side effect. A low TSH means the thyroid is overproducing hormones, which prompts additional blood work to confirm hyperthyroidism.
An ultrasound is the standard imaging tool. It reveals the gland’s size, shape, and whether any nodules are present. Ultrasound can also identify features that look suspicious, such as tiny calcium deposits within a nodule, irregular borders, or unusual blood flow patterns. When a nodule has these characteristics, or when part of the thyroid is growing rapidly or asymmetrically, a fine-needle aspiration biopsy may be recommended. This involves inserting a thin needle into the nodule to collect cells for examination under a microscope. For a typical, slow-growing, smooth goiter without suspicious nodules, biopsy usually isn’t necessary.
If a goiter is large enough to cause breathing or swallowing problems, CT or MRI scans can map exactly how much the gland is compressing the windpipe or extending into the chest cavity.
Treatment Options
Treatment depends on the goiter’s size, whether it’s causing symptoms, and what’s happening with your thyroid hormone levels.
Small, nontoxic goiters that aren’t causing symptoms often require nothing more than regular monitoring. Your doctor will check thyroid levels periodically and track the gland’s size over time. Many of these goiters stay stable for years.
When a goiter develops because of an underactive thyroid, thyroid hormone replacement medication can shrink the gland by reducing the signal that tells it to grow. This works best for diffuse goiters and is less effective for long-standing multinodular ones where the tissue has become more fibrous.
Toxic goiters producing excess hormone are initially treated with antithyroid medications to bring hormone levels back to normal. If medications don’t work, aren’t tolerated, or the goiter is too large, the next steps are typically surgery or radioactive iodine therapy. Radioactive iodine is taken as a capsule or liquid; it’s absorbed by thyroid cells, which gradually shrink and produce less hormone over several weeks to months. Surgery (partial or complete removal of the thyroid) is preferred when the goiter is very large, compressing the airway, or when there’s concern about cancer in a nodule.
After either radioactive iodine or surgery, most people need lifelong thyroid hormone replacement since the gland can no longer produce enough on its own.
Preventing Goiter Through Diet
Since iodine deficiency is the most common cause globally, getting enough iodine is the single most effective prevention strategy. The NIH recommends 150 mcg of iodine daily for adults, 220 mcg during pregnancy, and 290 mcg while breastfeeding. Children need less, ranging from 90 mcg for ages 1 to 8 up to 150 mcg for teenagers.
Iodized table salt is the simplest source. Just half a teaspoon of iodized salt contains roughly the full daily requirement for an adult. Other reliable dietary sources include seafood, dairy products, and eggs. Seaweed is particularly rich in iodine, though amounts vary widely by type. If you follow a restricted diet that limits salt and dairy, or if you use primarily sea salt or kosher salt (which are not typically iodized), you may want to check whether your intake is adequate.
Risks of Leaving a Goiter Untreated
Most goiters are benign and progress slowly, but ignoring a growing one carries real risks. The most serious mechanical complication is airway obstruction. As the thyroid enlarges, it can narrow the windpipe enough to cause wheezing, difficulty breathing during exertion, and in severe cases, acute respiratory distress. Retrosternal goiters, which grow downward into the chest, are especially prone to compressing the airway and major blood vessels.
There’s also a small but real risk of thyroid cancer within goiter nodules. Surgical studies have found incidental micropapillary carcinomas in thyroid tissue removed for what appeared to be benign goiters. This is one reason doctors monitor nodular goiters with periodic ultrasound rather than simply ignoring them.
A toxic goiter left untreated can lead to complications of prolonged hyperthyroidism, including bone thinning, irregular heart rhythms, and in older adults, heart failure. Even a nontoxic goiter can shift to overproduction of thyroid hormones over time, particularly in multinodular glands where individual nodules begin functioning independently.