Thyroiditis
Thyroiditis is a general term for inflammation of the thyroid gland. It includes several distinct conditions with different causes, features, and treatments. Common forms include Hashimoto thyroiditis (a chronic autoimmune condition that often causes hypothyroidism), subacute (de Quervain) thyroiditis (often following a viral illness and typically painful), silent and postpartum thyroiditis (autoimmune conditions with painless thyroid dysfunction), drug-induced thyroiditis (including from amiodarone, lithium, interferon, immune checkpoint inhibitors, and others), Riedel thyroiditis (a rare fibrotic condition), and acute suppurative thyroiditis (bacterial infection of the thyroid). Thyroid function may fluctuate through overactive, underactive, or normal phases depending on the type. Imaging and blood tests are central to diagnosis.
What is it?
The thyroid is a butterfly-shaped gland in the front of the neck that produces thyroid hormones, which regulate metabolism, heart rate, body temperature, and many other processes. Thyroiditis is a general term for inflammation of the thyroid gland. It is not a single disease but rather a group of distinct conditions with different causes, features, natural histories, and treatments. Some forms of thyroiditis produce painful thyroid enlargement, some are painless, and some fluctuate through different phases of thyroid function over time.
Hashimoto thyroiditis (also called chronic lymphocytic thyroiditis) is the most common autoimmune thyroid disease and one of the leading causes of hypothyroidism worldwide. It is characterized by immune-mediated infiltration and gradual destruction of the thyroid, often producing an enlarged, firm thyroid with characteristic ultrasound appearance and elevated thyroid antibodies (particularly anti-thyroid peroxidase, or anti-TPO). Many patients develop hypothyroidism over time, although some have normal thyroid function for years. Hashimoto thyroiditis is associated with an increased lifetime risk of primary thyroid lymphoma, an uncommon but important consideration when patients experience rapid thyroid enlargement.
Subacute (de Quervain) thyroiditis is a self-limited condition that often follows a viral upper respiratory infection. It typically produces neck pain (frequently radiating to the jaw or ear), tenderness of the thyroid, fever, and a triphasic pattern of thyroid function: an initial thyrotoxic phase (as inflammation releases stored thyroid hormone), followed by a hypothyroid phase, and eventually a return to normal function in most patients over weeks to months.
Silent and postpartum thyroiditis are autoimmune conditions that produce painless thyroid dysfunction, often with a similar triphasic pattern to subacute thyroiditis. Postpartum thyroiditis occurs in a proportion of women within about a year of delivery and can recur with subsequent pregnancies. Most patients recover normal thyroid function, but some develop persistent hypothyroidism.
Drug-induced thyroiditis can result from several medications, including amiodarone (which contains a large amount of iodine and can produce different patterns of thyroid dysfunction), lithium, interferon-alpha, tyrosine kinase inhibitors, and, increasingly recognized, immune checkpoint inhibitors used in cancer treatment. Recognition of drug-induced patterns is important because management depends on the specific medication, whether it can be safely stopped or continued, and coordination with the prescribing team.
Riedel thyroiditis (also called invasive fibrous thyroiditis) is a rare condition in which the thyroid gland is replaced by dense fibrous tissue that can extend into surrounding structures of the neck. It is often part of the spectrum of IgG4-related disease and can produce a hard, fixed neck mass with compressive symptoms.
Acute suppurative thyroiditis is a rare bacterial infection of the thyroid, typically presenting with rapid onset of severe neck pain, redness, fever, and systemic signs of infection. It may be associated with anatomical abnormalities such as a persistent pyriform sinus fistula, immunocompromise, or spread of infection from an adjacent site, and requires urgent evaluation.
Symptoms of thyroiditis vary widely based on the type and phase of disease. Neck pain and tenderness are more prominent in subacute and acute infectious thyroiditis, while Hashimoto, silent, and postpartum thyroiditis are usually painless. Hyperthyroid symptoms during the thyrotoxic phase may include palpitations, weight loss despite normal or increased appetite, tremor, heat intolerance, anxiety, sleep disturbance, and, less commonly, atrial fibrillation. Hypothyroid symptoms include fatigue, weight gain, cold intolerance, constipation, dry skin, hair changes, low mood, memory or concentration difficulty, menstrual changes, and, when severe, marked slowing of body functions. Some patients have no symptoms and are identified during routine blood testing or evaluation of thyroid enlargement.
Diagnosis combines clinical assessment, blood tests, and imaging. Blood tests typically include TSH as the primary screening test, with free T4, free T3, and thyroid antibodies (particularly anti-TPO and anti-thyroglobulin) added when abnormalities are found or when thyroiditis is suspected. Inflammatory markers (ESR and CRP) are often elevated in subacute and acute infectious thyroiditis. Ultrasound of the thyroid characterizes the gland’s size, echotexture, blood flow, and any nodules, and can distinguish patterns typical of specific forms of thyroiditis. Radioactive iodine uptake and scan is particularly useful in evaluating a thyrotoxic patient, since thyroiditis typically shows very low uptake (because stored hormone is released without new production), while Graves disease and toxic nodules show increased uptake—an important distinction because treatment differs significantly. Fine-needle aspiration biopsy is used in selected patients, particularly when a suspicious nodule is present or when Riedel thyroiditis, lymphoma, or acute suppurative thyroiditis is suspected. Cultures and additional imaging (CT or MRI) may be needed in acute suppurative or complicated cases.
Important to Know
Management of thyroiditis is directed at the specific type, phase of disease, and severity of symptoms. Care is best coordinated by primary care clinicians and endocrinologists, with involvement from otolaryngologists, general or endocrine surgeons, infectious disease specialists, oncologists (in the case of thyroid lymphoma in Hashimoto thyroiditis), obstetricians (in postpartum thyroiditis), and other specialists as needed.
For Hashimoto thyroiditis, treatment focuses on managing hypothyroidism when it develops. Levothyroxine (thyroid hormone replacement) is the standard treatment for overt hypothyroidism and, in selected patients with symptoms or specific circumstances, subclinical hypothyroidism. Dose is adjusted based on TSH and clinical response and typically requires periodic monitoring. Patients with Hashimoto thyroiditis who are euthyroid (normal thyroid function) generally do not need treatment but benefit from monitoring of thyroid function over time. During pregnancy and preconception, thyroid hormone requirements often increase and require close monitoring in coordination with obstetrics.
For subacute (de Quervain) thyroiditis, treatment focuses on symptom control while the illness runs its self-limited course. Nonsteroidal anti-inflammatory drugs are often first-line for pain and inflammation. Beta blockers may be used to control symptoms of the thyrotoxic phase without treating the underlying inflammation. Oral corticosteroids are used for patients with severe or refractory pain and typically produce rapid symptom improvement, with gradual dose tapering over weeks to months. Most patients eventually recover normal thyroid function, although a small proportion develop persistent hypothyroidism requiring long-term levothyroxine.
For silent and postpartum thyroiditis, treatment is similar in principle to subacute thyroiditis but usually does not require corticosteroids because the process is painless. Beta blockers are used for hyperthyroid symptoms during the thyrotoxic phase. Levothyroxine is used during the hypothyroid phase or for persistent hypothyroidism. Because postpartum thyroiditis often occurs during a demanding time in a woman’s life, awareness and mental health support are important. Recurrence in subsequent pregnancies is common.
For drug-induced thyroiditis, management is highly individualized. Some medications must be continued for the primary condition (such as amiodarone for serious arrhythmias or immune checkpoint inhibitors for cancer), and thyroid dysfunction is managed with beta blockers, levothyroxine, or antithyroid medications as appropriate. Coordination with the prescribing team is essential to weigh the risks and benefits of continuing, stopping, or substituting the responsible medication. Immune checkpoint inhibitor–related thyroiditis is now a recognized and increasingly common cause of thyroid dysfunction in patients receiving cancer immunotherapy.
For Riedel thyroiditis, treatment involves specialist care and may include glucocorticoids, other immunomodulatory therapies, and, when complications such as compressive symptoms occur, careful surgical evaluation. Because Riedel thyroiditis is often part of IgG4-related disease, evaluation for involvement of other organs may be appropriate.
For acute suppurative thyroiditis, urgent hospital care is typically needed. Treatment includes intravenous antibiotics tailored to the identified or suspected organisms, drainage of any abscess, and evaluation for underlying anatomical abnormalities (such as a persistent pyriform sinus fistula, which may require additional treatment to prevent recurrence). Coordination with infectious disease and otolaryngology is important.
For patients with Hashimoto thyroiditis who experience rapid thyroid enlargement, new or firm neck masses, unusual local symptoms, or systemic symptoms such as fever, night sweats, or weight loss, prompt evaluation for possible thyroid lymphoma is important, though the condition remains uncommon.
Lifestyle measures play a supportive role. A balanced diet, adequate iodine intake (with caution against excessive supplementation from high-dose iodine or kelp supplements), regular physical activity, adequate sleep, and management of general health conditions all support overall wellbeing. Selenium, gluten-free diets, and other dietary interventions are sometimes suggested for Hashimoto thyroiditis but currently have limited evidence and should not replace standard medical care.
Care is typically coordinated by primary care clinicians and endocrinologists, with involvement from other specialists as needed. Imaging and laboratory findings are interpreted alongside the patient’s symptoms, examination, family history, medications, and broader clinical context rather than in isolation.
Patient education plays an important role. Understanding the specific type of thyroiditis, the expected course, the rationale for recommended monitoring or treatment, medication adherence, and warning signs of complications all contribute to better outcomes.
Red flag symptoms include rapid enlargement of the neck, new or progressive difficulty breathing, stridor (noisy breathing), difficulty swallowing solids or liquids, severe neck pain with high fever and chills (which may suggest acute suppurative thyroiditis or abscess), symptoms of severe hyperthyroidism (such as severe palpitations, chest pain, marked weight loss, severe tremor, agitation, or high fever with confusion, which may indicate thyroid storm), severe hypothyroidism symptoms (such as extreme fatigue, confusion, hypothermia, or slowed breathing, which may indicate myxedema), signs of atrial fibrillation with dizziness or fainting, or sudden severe symptoms of unknown cause. These warrant prompt or urgent medical evaluation.