Thyroiditis is a common thyroid disorder, but there are several types, and the causes are not the same for different types of thyroiditis. Subacute thyroiditis: Also known as granulomatous thyroiditis and giant cell thyroiditis. It is a self-limiting thyroiditis associated with viral infections such as influenza virus, coxsackievirus, adenovirus, and mumps virus. 10%-20% of patients may find autoantibodies to the thyroid gland during the subacute phase, but the antibodies also disappear when the disease resolves, and the vast majority can be cured in a few days, usually without residual symptoms. Autoimmune thyroiditis: A large group of thyroid infections associated with autoimmune reactions. Their common features are the presence of serum antibodies against the thyroid gland itself and the presence of infiltrating lymphocytes in the thyroid gland, but the degree of thyroid destruction is not necessarily proportional to the symptoms of hypothyroidism. Common types of disease include: Hashimoto’s thyroiditis, atrophic thyroiditis, quiet thyroiditis, postpartum thyroiditis, medicated thyroiditis, and Hashimoto’s thyrotoxicosis. Painless thyroiditis: the infiltration of lymphocytes in the thyroid gland is mild, with only a focal infiltrate that manifests as transient reversible thyroid follicular destruction. In half of the patients, the thyroid gland is mildly enlarged, diffuse, hard in texture, and without local tenderness. The thyrotoxicosis of this disease is due to the destruction of thyroid follicles by inflammation and leakage of thyroid hormones into the circulation. Postpartum thyroiditis is also a variant of painless thyroiditis. Acute septic thyroiditis: It is a rare or rare inflammation of the thyroid gland, mainly seen in children, mostly due to abnormal thyroid development or with other abnormalities of the neck, followed by bacterial