Thyroiditis is a group of diseases characterized by inflammation of the thyroid gland as a common feature. Its main symptoms are usually caused by hyperthyroidism and hypothyroidism, so the preferred department for consultation is endocrinology. The clinical classification of thyroiditis is diverse and can be classified by etiology as bacterial, viral, autoimmune, post-radiation, parasitic, tuberculosis, syphilis, and HIV infection. The most common clinical thyroiditis are chronic lymphocytic thyroiditis and subacute granulomatous thyroiditis. Painless thyroiditis is also frequently seen clinically; the most common from an etiologic perspective is autoimmune thyroiditis. Most patients with thyroiditis present mainly with transient hyperthyroidism or hypothyroidism and are therefore treated mainly through endocrinology. Some patients will have concomitant systemic autoimmune disease, or thyroid symptoms that are themselves part of a systemic autoimmune disease, and may also be treated in a rheumatology emergency with adjunctive endocrine therapy. Other patients with significant thyroid masses or symptoms of compression that require surgery may also be seen in head and neck surgery or thyroid specialists for adjuvant endocrine therapy. Some patients with bacterial thyroiditis, with obvious symptoms of infection and normal nail function, can be seen in surgery for anti-infection treatment. Therefore, patients with autoimmune thyroiditis are most often treated by endocrinology, and can be seen in head and neck surgery, rheumatology and thyroid specialists if necessary.