Introduction Self-limiting hypothyroidism following a viral infection (URI) early on may be hyperthyroid (similar to Hashimoto's) later, symptomatology is hypothyroid (though this is not permanent) Presentation Physical exam jaw pain very tender thyroid gland post-partum lymphocytic subacute thyroiditis is painless no cervical adenopathy Evaluation Labs ↑ ESR hyperthyroid phase: high T4, high T3, low TSH euthyroid phase: normal T4, T3, TSH hypothyroid phase: normal/low T4 and T3, elevated TSH Histology granulomatous inflammation 123I uptake decreased Treatment Manage symptoms (pain) with NSAIDS and aspirin Does not require treatment Prognosis, Prevention, and Complications Rare to progress to permanent hypothyroidism