The causes of thyroiditis are varied and include bacterial infections, viral infections, autoimmunity, radiation damage, medications, trauma, and many other factors. Bacterial infections such as staphylococcus, streptococcus, and pneumococcus can cause acute thyroiditis. Infections such as coxsackie virus, mumps virus, influenza virus, and adenovirus can cause subacute thyroiditis. In addition, factors such as genetic susceptibility and the environment are associated with the development of autoimmune thyroiditis. Radiation thyroiditis, associated with a history of radiation therapy to the neck.