1. Since the early onset of subacute thyroiditis is often accompanied by symptoms of upper respiratory tract infections such as colds, followed by fever, anterior neck pain, sore throat, and aggravated swallowing, it can easily be misdiagnosed as epiglottitis or pharyngitis, and then given antimicrobial treatment leading to delayed illness. Therefore, patients with fever with neck and throat pain should consider the possibility of subacute thyroiditis and undergo thyroid-related tests. As the thyroid tissue is destroyed during the onset of subacute thyroiditis, a large amount of thyroid hormones are released into the blood, resulting in elevated T3 and T4, resulting in hyperthyroid symptoms such as panic and fear of heat, which can be easily misdiagnosed as hyperthyroidism and treated with a large amount of antithyroid drugs or even surgery. Subacute thyroiditis can be distinguished from hyperthyroidism by an increase in T3 and T4 and a decrease in iodine uptake by the thyroid gland. In addition, the difference can be made from the urgency of the onset, the duration of the disease, and the presence or absence of proptosis. In general, subacute thyroiditis has an acute onset and is accompanied by fever. If the disease is severe, a few patients may develop symptoms of hypothyroidism, which can be easily misdiagnosed.