Table 2 Causes of painful thyroid and some discriminating features

Common

Subacute thyroiditis

Diffuse pain (may be localized), increased inflammatory markers

Hemorrhage into a thyroid cyst or nodule

Localized pain, detectable nodule/cyst on physical examination or ultrasound

Less common

Acute infectious (suppurative) thyroiditis

Localized pain, history of immunosuppression or congenital anomaly (e.g., piriform sinus fistula), abscess formation

Thyroid trauma

Diffuse or localized pain, history of trauma

Radiation-induced thyroiditis

Diffuse pain, history of radiation exposure (contraindicated in pregnancy)

Rapid enlargement of thyroid carcinoma

Localized pain, detectable tumor often with extrathyroidal extension

Rare

Autoimmune thyroiditis

Diffuse pain, positive immune markers (thyroid peroxidase and thyroglobulin antibodies)

Drug-induced thyroiditis (e.g., amiodarone)

Diffuse pain, positive drug history

Thyroid lymphoma

Localized pain, very firm and enlarged thyroid, extrathyroid involvement common