Clinical manifestations in patients with subacute thyroiditis include neck pain, which may also be accompanied by headache and radiating pain behind the ear. There may also be systemic symptoms, such as malaise, fever, loss of appetite, tachycardia, and excessive sweating. Moreover, the patient’s thyroid gland may be palpably enlarged, indurated, and hard. There is individual variability in clinical manifestations. Patients with subacute thyroiditis have normal or mildly elevated concentrations of white blood cells in the blood, and there is accelerated blood sedimentation. Ultrasonography of the thyroid gland may suggest a patchy hypoechoic inflammatory manifestation in the thyroid gland. Elevated serum thyroid hormone concentrations and a thyroid iodine uptake rate that is markedly lower than normal and bi-directional separation can confirm the diagnosis of subacute thyroiditis. Patients suspected of having subacute thyroiditis are advised to go to the hospital for timely examination and follow the doctor’s instructions for standardized treatment.