Thyroiditis is an inflammation of the thyroid gland, which is located in the front of the neck. This condition can affect how the gland functions, leading to either an underactive or overactive thyroid. Common types of thyroiditis include Hashimoto's thyroiditis, which is an autoimmune disorder, and subacute thyroiditis, often triggered by a viral infection. Symptoms of thyroiditis can vary but may include fatigue, weight changes, and sensitivity to temperature. Diagnosis typically involves blood tests to check hormone levels and antibodies. Treatment options depend on the type and severity of the condition, ranging from medication to manage symptoms to hormone replacement therapy.