How to manage subacute thyroiditis

Subacute thyroiditis (SAT) is a self-limited inflammatory thyroid disorder classically characterized by anterior neck pain, an enlarged tender thyroid, fever, fatigue, malaise, elevated inflammatory markers and a triphasic course from thyrotoxicosis through hypothyroidism to recovery. It can cause substantial morbidity and remains a frequent diagnostic challenge because it must be distinguished from acute suppurative thyroiditis, Graves' disease, painless thyroiditis, haemorrhage into a nodule and, rarely, malignant 'pseudothyroiditis' (rapidly growing carcinoma). In recent years, the recognized spectrum of triggers has expanded beyond the classical post-viral setting to include SARS-CoV-2 infection or vaccination. This review summarizes current understanding of SAT pathogenesis, including viral and post-viral mechanisms, and HLA-linked susceptibility. We outline the typical and variant clinical phenotypes, emphasising painful classical SAT, painless presentations, pregnancy-associated disease and therapy-related destructive thyroiditis. We then present a practical diagnostic framework based on clinical features, inflammatory markers, thyroid function tests, radionuclide imaging, ultrasound and fine-needle aspiration, when indicated. Management is discussed in a stepwise fashion, including NSAIDs and glucocorticoids for pain and inflammation, β-blockers for symptomatic thyrotoxicosis, selective levothyroxine replacement during the hypothyroid phase, and structured follow-up to detect recurrence and permanent hypothyroidism. Special attention is given to pregnancy and SARS-CoV-2-related SAT cases. Finally, we review long-term outcomes, recurrence risk and future research priorities. The aim is to provide a concise, clinically oriented guide to the contemporary management of SAT and to support rational, evidence-informed decision-making in routine endocrine practice.