Thyroiditis: Symptoms, Causes & Treatment

What Is Thyroiditis?

Thyroiditis is inflammation of the thyroid gland, a butterfly-shaped organ in the front of the neck that produces hormones controlling metabolism, energy levels, and body temperature. The inflammation disrupts normal hormone production, initially releasing excess hormones (hyperthyroidism) before the gland becomes depleted and underactive (hypothyroidism).

The thyroid gland is one of the most important endocrine organs in the body. Located at the front of the neck, wrapped around the trachea (windpipe), this small gland weighs only about 20 grams but produces hormones that influence virtually every cell and organ system. The thyroid produces two main hormones: thyroxine (T4) and triiodothyronine (T3), which regulate how quickly cells convert nutrients into energy—a process called metabolism.

When the thyroid becomes inflamed, the normal architecture of the gland is disrupted. The thyroid normally stores a small reserve of pre-made hormones, and inflammation causes these stored hormones to leak into the bloodstream. This sudden release creates an excess of thyroid hormones in the body, a condition called thyrotoxicosis. Unlike hyperthyroidism caused by an overactive gland (such as Graves' disease), thyrotoxicosis from thyroiditis occurs because stored hormones are being released, not because the gland is producing more.

After the initial hormone release depletes the thyroid's reserves, the inflamed gland often cannot produce adequate hormones to meet the body's needs. This second phase results in hypothyroidism, characterized by low energy, weight gain, and feeling cold. For most people with temporary thyroiditis, the gland eventually heals and normal function returns. However, some individuals—particularly those with autoimmune thyroiditis—develop permanent hypothyroidism requiring lifelong hormone replacement therapy.

The thyroid's role in the body

Understanding why thyroiditis causes such diverse symptoms requires appreciating the thyroid's central role in metabolism. Thyroid hormones affect virtually every organ system: they regulate heart rate and cardiac output, influence brain development and cognitive function, control body temperature, affect digestive function, and maintain healthy skin, hair, and nails. The hormones also play crucial roles in bone metabolism, menstrual regularity, and fertility.

The thyroid gland is controlled by the pituitary gland, a pea-sized organ at the base of the brain. The pituitary produces thyroid-stimulating hormone (TSH), which signals the thyroid to make and release T4 and T3. When thyroid hormone levels rise, the pituitary reduces TSH production, and when hormone levels fall, TSH increases. This feedback loop normally keeps hormone levels stable, but thyroiditis disrupts this delicate balance.

Who gets thyroiditis?

Thyroiditis affects people of all ages and backgrounds, but certain groups face higher risk. Women are significantly more affected than men, with some types occurring 4 to 10 times more frequently in females. The reasons for this gender disparity aren't fully understood but likely involve differences in immune system function and hormonal influences. Autoimmune thyroiditis (Hashimoto's disease), the most common type, often runs in families and may occur alongside other autoimmune conditions like type 1 diabetes, celiac disease, or rheumatoid arthritis.

What Are the Symptoms of Thyroiditis?

Thyroiditis symptoms occur in two phases: initial hyperthyroid symptoms (sweating, rapid heartbeat, anxiety, weight loss, tremors) lasting 1-2 months, followed by hypothyroid symptoms (fatigue, weight gain, cold intolerance, constipation, depression) lasting 1-3 months. Some types also cause neck pain, fever, and visible thyroid swelling (goiter).

The symptoms of thyroiditis reflect the underlying hormonal changes occurring in the body. Because thyroiditis typically progresses through distinct phases—from inflammation to hyperthyroidism to hypothyroidism to recovery—the symptoms you experience depend largely on which phase you're in. Additionally, some types of thyroiditis cause local symptoms from the inflammation itself, while others are "silent," causing only hormonal symptoms without pain or obvious swelling.

Symptoms from inflammation

When thyroiditis is caused by viral infection (subacute thyroiditis) or, more rarely, bacterial infection (acute thyroiditis), the inflammation itself produces noticeable symptoms. The thyroid gland becomes tender to touch, and you may feel pain in the front of the neck that can radiate upward to the jaw, ears, or back of the head. This pain often worsens when swallowing or turning the head. Many people describe it as feeling like a severe sore throat.

The thyroid may enlarge and become visible or palpable as a swelling at the base of the neck—a condition called goiter. The gland often feels firm or even hard during examination. Fever is common with subacute thyroiditis, sometimes reaching 38-39°C (100-102°F), accompanied by general malaise, fatigue, and muscle aches similar to a viral illness. These inflammatory symptoms can be quite severe initially but typically improve within days to weeks, especially with appropriate treatment.

Importantly, some types of thyroiditis—including silent thyroiditis and autoimmune thyroiditis—cause no local symptoms whatsoever. You won't feel pain, tenderness, or fever. This is why these conditions are called "painless" or "silent" thyroiditis. They're only detected when blood tests reveal abnormal hormone levels or when symptoms of hyperthyroidism or hypothyroidism prompt investigation.

Symptoms of high thyroid hormone levels (hyperthyroidism)

During the initial phase of thyroiditis, excess thyroid hormone released into the bloodstream accelerates metabolism throughout the body. This creates a distinctive constellation of symptoms that can range from mild to severe depending on how much hormone is released. Common hyperthyroid symptoms include:

• Heat intolerance and excessive sweating: You may feel uncomfortably warm even in cool environments and sweat more than usual
• Rapid heartbeat (tachycardia) and palpitations: The heart beats faster and you may be aware of your heartbeat pounding
• Weight loss despite normal or increased appetite: Accelerated metabolism burns more calories
• Anxiety, nervousness, and irritability: Excess hormones affect brain chemistry
• Sleep disturbances: Difficulty falling asleep or staying asleep despite feeling tired
• Tremor: Fine shaking of the hands, especially noticeable when holding objects
• Frequent bowel movements or diarrhea: Digestive system speeds up
• Muscle weakness: Particularly noticeable when climbing stairs or rising from a chair

The hyperthyroid phase of thyroiditis typically lasts one to two months. For some people, symptoms are mild and barely noticeable. Others experience significant symptoms that affect daily life and work. The severity depends on how much stored hormone is released and how quickly the release occurs.

Symptoms of low thyroid hormone levels (hypothyroidism)

After the thyroid's hormone stores are depleted, the damaged gland may be unable to produce adequate hormones to meet the body's needs. This hypothyroid phase typically begins one to two months after the initial inflammation and can last one to three months before recovery. During this phase, metabolism slows throughout the body:

• Fatigue and low energy: Feeling tired despite adequate sleep, lacking motivation
• Weight gain: Often modest (2-5 kg) despite unchanged eating habits
• Cold intolerance: Feeling chilly when others are comfortable, needing extra layers
• Constipation: Digestive system slows down significantly
• Dry skin and brittle hair: Reduced cellular turnover affects skin and hair quality
• Depression and cognitive changes: Feeling low, having difficulty concentrating, memory problems
• Muscle aches and stiffness: Generalized discomfort, especially in the morning
• Menstrual irregularities: Heavier or irregular periods in women
• Fluid retention: Mild swelling of the face, particularly around the eyes

Many people tolerate mild hypothyroidism reasonably well and may not need treatment during this phase, as hormone levels often normalize spontaneously. However, more severe hypothyroidism causes significant impairment and may require temporary hormone replacement therapy.

When Should You See a Doctor for Thyroiditis?

See a doctor if you experience unexplained fatigue, neck pain or swelling, heart palpitations, unexplained weight changes, or fever with thyroid tenderness. Seek immediate medical attention for difficulty breathing, severe neck swelling, very rapid heartbeat, confusion, or high fever—these may indicate serious complications requiring urgent care.

Recognizing when thyroiditis symptoms warrant medical attention is important for both proper diagnosis and appropriate treatment. While most cases of thyroiditis are not emergencies, some situations require prompt evaluation to rule out more serious conditions or to prevent complications.

Schedule an appointment with your doctor if you experience any of the following:

• Unexplained fatigue that persists for more than a few weeks
• Neck pain or tenderness in the thyroid area (front of the neck)
• Visible swelling or a lump in the front of your neck
• Heart palpitations or awareness of a rapid heartbeat
• Unexplained weight changes (either gain or loss)
• Increased sensitivity to heat or cold
• Fever accompanied by neck pain or tenderness
• New or worsening anxiety, nervousness, or depression
• Changes in menstrual patterns

How Is Thyroiditis Diagnosed?

Thyroiditis is diagnosed through blood tests measuring TSH, free T4, and free T3 hormone levels, plus thyroid antibody tests to identify autoimmune causes. Additional tests may include ultrasound to visualize the gland, radioactive iodine uptake scan (scintigraphy) to distinguish thyroiditis from Graves' disease, and occasionally fine-needle biopsy to rule out other conditions.

Diagnosing thyroiditis involves a combination of clinical evaluation, blood tests, and sometimes imaging studies. Your doctor will begin by asking detailed questions about your symptoms, their duration and progression, any recent illnesses (particularly upper respiratory infections), pregnancy history, family history of thyroid disorders, and any medications you're taking.

Physical examination

During the physical examination, your doctor will carefully examine your thyroid gland by feeling (palpating) your neck. They'll assess the thyroid's size, texture, and whether it's tender to touch. In subacute thyroiditis, the gland is typically enlarged, firm, and quite tender. In silent or autoimmune thyroiditis, the gland may be enlarged but painless. Your doctor will also check your heart rate, look for signs of tremor, assess your reflexes, and examine your skin and eyes.

Blood tests

Blood tests are essential for confirming thyroiditis and determining its phase and type. The key tests include:

• TSH (thyroid-stimulating hormone): This is usually the first test ordered. Low TSH suggests hyperthyroidism; high TSH suggests hypothyroidism
• Free T4 and Free T3: These measure the actual thyroid hormone levels in your blood. Elevated levels confirm hyperthyroidism; low levels confirm hypothyroidism
• Thyroid antibodies: TPO (thyroid peroxidase) antibodies and thyroglobulin antibodies help identify autoimmune thyroiditis. These are elevated in Hashimoto's disease and often in silent or postpartum thyroiditis
• ESR and CRP: These inflammatory markers are elevated in subacute thyroiditis but normal in silent or autoimmune thyroiditis

Because thyroiditis progresses through phases, your doctor may order repeat blood tests over time to track how hormone levels change. This helps confirm the diagnosis and guide treatment decisions.

Imaging and additional tests

Thyroid ultrasound uses sound waves to create images of the thyroid gland. It can show enlargement, inflammation patterns, nodules, or other structural abnormalities. Ultrasound is painless and doesn't involve radiation.

Radioactive iodine uptake scan (scintigraphy) is particularly useful for distinguishing thyroiditis from other causes of hyperthyroidism. In thyroiditis, the thyroid's iodine uptake is low because the gland isn't actively producing hormones—it's simply releasing stored hormones. In contrast, conditions like Graves' disease show increased uptake because the gland is overproducing hormones. This test involves taking a small amount of radioactive iodine and imaging the thyroid 4-24 hours later.

Fine-needle aspiration biopsy is occasionally performed if there's uncertainty about the diagnosis, particularly if nodules are present or if the clinical picture is unusual. A thin needle is used to extract cells from the thyroid for microscopic examination. This test is typically done alongside ultrasound guidance and is generally well-tolerated.

What Are the Different Types of Thyroiditis?

The main types of thyroiditis are: subacute (de Quervain's) thyroiditis caused by viral infection; Hashimoto's thyroiditis (autoimmune, chronic); silent thyroiditis (autoimmune, painless); postpartum thyroiditis occurring after pregnancy; acute thyroiditis (rare, bacterial); and drug-induced thyroiditis from medications like lithium or interferon.

Thyroiditis encompasses several distinct conditions that share the common feature of thyroid inflammation but differ in their causes, presentation, and long-term outcomes. Understanding the specific type of thyroiditis is important because it influences treatment decisions and helps predict the likely course of the illness.

Subacute thyroiditis (de Quervain's thyroiditis)

Subacute thyroiditis is typically triggered by a viral infection. Many patients recall having an upper respiratory infection, flu-like illness, or other viral illness about 2-8 weeks before thyroiditis symptoms began. The condition causes significant inflammation with characteristic painful swelling of the thyroid gland. Fever, fatigue, and general malaise are common.

The hyperthyroid phase of subacute thyroiditis usually lasts 3-6 weeks, followed by a hypothyroid phase lasting 2-3 months. Most patients (85-95%) recover fully within 6-12 months with normal thyroid function. However, about 5-15% develop permanent hypothyroidism requiring lifelong thyroid hormone replacement. Subacute thyroiditis can recur, though this is uncommon.

Hashimoto's thyroiditis (autoimmune thyroiditis)

Hashimoto's disease is the most common type of thyroiditis and the leading cause of hypothyroidism in areas with adequate iodine intake. It's an autoimmune condition in which the immune system attacks thyroid tissue, causing chronic inflammation that gradually destroys the gland's ability to produce hormones.

Unlike subacute thyroiditis, Hashimoto's develops slowly over months to years and is typically painless. Most people don't notice symptoms until significant hypothyroidism develops. The condition is much more common in women (7-10 times more than men) and often runs in families. It frequently occurs alongside other autoimmune conditions. Hashimoto's thyroiditis cannot be cured, but hypothyroidism is easily managed with daily thyroid hormone replacement medication.

Silent thyroiditis (painless thyroiditis)

Silent thyroiditis causes the classic two-phase pattern of thyroiditis (hyperthyroidism followed by hypothyroidism) but without pain, tenderness, or fever. It's called "silent" because the only symptoms come from hormonal changes, not from inflammation. The cause is autoimmune, similar to Hashimoto's, and patients often have elevated thyroid antibodies.

Silent thyroiditis follows a milder course than subacute thyroiditis. Most patients recover normal thyroid function within 12-18 months, though about 10-20% develop permanent hypothyroidism. The condition can recur, with some patients experiencing multiple episodes over years.

Postpartum thyroiditis

Postpartum thyroiditis is a special form of silent thyroiditis that occurs in women within the first year after giving birth (usually 2-6 months postpartum). It affects approximately 5-10% of women after pregnancy. The condition occurs because immune system changes during pregnancy temporarily suppress autoimmune activity, which then rebounds after delivery.

Many cases are missed because symptoms overlap with the normal challenges of caring for a newborn—fatigue, mood changes, and sleep disruption are common in new mothers regardless of thyroid status. Women who develop postpartum thyroiditis have increased risk of developing permanent hypothyroidism later in life and should have periodic thyroid monitoring.

Acute thyroiditis (suppurative thyroiditis)

Acute thyroiditis is rare but serious, caused by bacterial infection of the thyroid gland. It occurs most often in people with immune system problems or pre-existing thyroid abnormalities that create a pathway for bacteria to enter. Symptoms include severe neck pain, high fever, difficulty swallowing, and systemic illness. The condition requires hospitalization, intravenous antibiotics, and sometimes surgical drainage. Without treatment, it can be life-threatening.

Drug-induced thyroiditis

Certain medications can cause thyroid inflammation and dysfunction. The most common culprits include:

• Lithium: Used for bipolar disorder, can cause both hypothyroidism and thyroiditis
• Amiodarone: A heart medication that can cause hyperthyroidism or hypothyroidism
• Interferon-alpha: Used for hepatitis and some cancers, can trigger autoimmune thyroiditis
• Immune checkpoint inhibitors: Cancer immunotherapy drugs that can cause autoimmune thyroiditis

How Is Thyroiditis Treated?

Thyroiditis treatment depends on the phase and severity: anti-inflammatory medications (NSAIDs or corticosteroids) for pain and inflammation; beta-blockers to control hyperthyroid symptoms like rapid heartbeat; and levothyroxine (thyroid hormone replacement) if hypothyroidism develops. Many mild cases require only monitoring without active treatment.

Treatment for thyroiditis is tailored to the type of thyroiditis, the current phase of the illness, and the severity of symptoms. Because many cases of temporary thyroiditis resolve on their own, treatment often focuses on symptom relief rather than trying to cure the underlying condition. Your doctor will monitor your hormone levels with periodic blood tests and adjust treatment as your condition evolves.

Treatment for inflammation and pain

For subacute thyroiditis with significant pain and fever, anti-inflammatory treatment provides relief. Mild cases often respond well to over-the-counter NSAIDs (non-steroidal anti-inflammatory drugs) such as ibuprofen or naproxen. These medications reduce inflammation, relieve pain, and lower fever.

More severe cases may require corticosteroids (such as prednisone), which are powerful anti-inflammatory medications. Corticosteroids typically produce dramatic improvement within 24-48 hours. Treatment usually starts at a moderate dose and is gradually tapered over 4-8 weeks. Stopping corticosteroids too quickly can cause symptoms to return, so it's important to follow the tapering schedule your doctor prescribes.

If you're taking corticosteroids for an extended period, your doctor will monitor for potential side effects. Long-term corticosteroid use can affect blood sugar, bone density, and immune function. However, for the relatively short courses used in thyroiditis, serious complications are uncommon.

Treatment for hyperthyroid symptoms

During the hyperthyroid phase, treatment aims to control symptoms rather than suppress thyroid function. Unlike Graves' disease or toxic nodular goiter (where the thyroid is overproducing hormones), the hyperthyroidism in thyroiditis results from hormone release from a damaged gland. Anti-thyroid medications that block hormone production are not effective because the gland isn't actively making excess hormones.

Beta-blockers are the primary treatment for hyperthyroid symptoms. Medications like propranolol or atenolol slow the heart rate, reduce palpitations, decrease tremor, and relieve anxiety. They work quickly and effectively for symptom control. Beta-blockers are usually needed for only a few weeks until the hyperthyroid phase passes.

Treatment for hypothyroid symptoms

During the hypothyroid phase, treatment depends on symptom severity and hormone levels. Many people with mild hypothyroidism feel reasonably well and don't require treatment, especially knowing that hormone levels are likely to normalize. Your doctor may simply monitor your blood tests and symptoms.

For more significant hypothyroidism causing bothersome symptoms, temporary levothyroxine (synthetic thyroid hormone) replacement may be prescribed. The dose is carefully adjusted based on blood tests. As your thyroid recovers, the medication can gradually be reduced and eventually stopped. Your doctor will check hormone levels periodically to ensure timing is appropriate.

For permanent hypothyroidism (as in Hashimoto's disease or after permanent damage from other types), lifelong levothyroxine therapy is needed. This medication is very safe, well-tolerated, and simply replaces what your thyroid can no longer make. Once the correct dose is established, most people feel completely normal and require only annual blood test monitoring.

Treatment during pregnancy and breastfeeding

Thyroid disorders during pregnancy require careful management because thyroid hormones are crucial for fetal brain development. If you develop thyroiditis while pregnant or breastfeeding, your doctor will closely monitor your hormone levels and treat when necessary. Most thyroid medications, including levothyroxine and certain beta-blockers, are safe during pregnancy and breastfeeding when medically indicated.

Women with postpartum thyroiditis should be monitored closely, and those with significant symptoms may need temporary treatment. The decision to treat depends on hormone levels, symptoms, and whether you're breastfeeding. Your doctor will help weigh the benefits and risks of different treatment options.

How Does Thyroiditis Affect Daily Life?

Thyroiditis can significantly impact daily life, with fatigue being the most common complaint. Many people need 1-2 months off work during acute phases. The illness typically runs its course within 6 months, with most people returning to normal function. Those developing permanent hypothyroidism manage well with daily medication.

The impact of thyroiditis on daily life varies considerably depending on the type, severity, and phase of the illness. Understanding what to expect can help you plan and cope with the challenges.

During the acute inflammatory phase of subacute thyroiditis, neck pain and fever can be quite debilitating. Many people find they need several days to weeks of reduced activity while symptoms are most severe. Once anti-inflammatory treatment begins working (usually within 24-48 hours for corticosteroids), improvement is rapid.

The hyperthyroid phase can cause significant fatigue despite feeling "wired" or anxious. Sleep disturbances, heart palpitations, and difficulty concentrating can affect work performance and quality of life. The hypothyroid phase often brings different challenges: profound fatigue, difficulty thinking clearly, and low mood. Many people describe feeling like they're "running on empty" or thinking through a fog.

For temporary thyroiditis, it's reassuring to know that symptoms will eventually resolve. The entire process typically takes 6-12 months from start to finish. During recovery, energy and wellbeing gradually return to normal. Regular blood test monitoring helps track progress and guides any treatment adjustments.

Those who develop permanent hypothyroidism (whether from Hashimoto's disease or as a consequence of other thyroiditis) generally do very well with hormone replacement therapy. Once the correct levothyroxine dose is established, most people feel completely normal and live without restrictions. The medication becomes simply a daily habit, like taking a vitamin.

What Causes Thyroiditis?

Thyroiditis causes include viral infections (most common for subacute thyroiditis), autoimmune dysfunction (Hashimoto's, silent, postpartum), bacterial infections (rare acute thyroiditis), and certain medications. Genetic factors play a role in autoimmune types, which often run in families and occur more frequently in women.

The causes of thyroiditis vary by type, but they all result in inflammation that disrupts normal thyroid function. Understanding the underlying cause helps predict the course of illness and guide treatment.

Viral causes

Subacute thyroiditis is believed to be triggered by viral infections. While the exact virus often isn't identified, the condition frequently follows upper respiratory infections, influenza, mumps, measles, or other viral illnesses. The viral infection likely triggers an inflammatory response that affects the thyroid either through direct viral damage or through an immune reaction. Some evidence suggests genetic susceptibility, as subacute thyroiditis occurs more frequently in people with certain immune system gene variants.

Autoimmune causes

Hashimoto's thyroiditis, silent thyroiditis, and postpartum thyroiditis all involve autoimmune dysfunction. In these conditions, the immune system mistakenly recognizes thyroid tissue as foreign and produces antibodies that attack the gland. Why this happens isn't fully understood, but multiple factors contribute:

• Genetic predisposition: Autoimmune thyroid disease runs strongly in families. Having a first-degree relative with Hashimoto's or Graves' disease significantly increases your risk
• Environmental triggers: Infections, high iodine intake, certain medications, and possibly stress may trigger autoimmunity in genetically susceptible individuals
• Female hormones: The strong female predominance suggests that estrogen and other sex hormones influence thyroid autoimmunity
• Other autoimmune conditions: Having one autoimmune disease increases risk for others, including thyroiditis

Bacterial causes

Acute (suppurative) thyroiditis is caused by bacterial infection, most commonly Staphylococcus aureus, Streptococcus species, or other bacteria. These infections typically reach the thyroid through the bloodstream, from adjacent structures (like a piriform sinus fistula—an abnormal connection from the throat), or rarely through direct trauma. Pre-existing thyroid abnormalities and immune system problems increase susceptibility.

Medication causes

Several medications can cause or contribute to thyroid inflammation and dysfunction. Lithium, amiodarone, interferon, and newer cancer immunotherapies are well-recognized causes. The mechanisms vary: some drugs directly damage thyroid cells, while others trigger autoimmune reactions. If you develop thyroid problems while taking these medications, your doctor will evaluate whether the drug can be continued, modified, or replaced.