Hashimoto's thyroiditis belongs to autoimmune thyroiditis, where the body's own antibodies destroy the thyroid follicular cells, leading to apoptosis of thyroid cells. As the disease progresses, it may lead to hypothyroidism. Generally, Hashimoto's thyroiditis does not cause fever. If a patient with Hashimoto's thyroiditis experiences a fever, it is necessary to exclude other infectious diseases. If a patient with Hashimoto's thyroiditis has a fever, especially if there is significant tenderness in the thyroid area, it is necessary to exclude the possibility of concomitant subacute thyroiditis. If Hashimoto's thyroiditis is accompanied by subacute thyroiditis, small doses of hormones can be used for treatment. (Please use medication under the guidance of a doctor.)