Subacute thyroiditis is acute inflammation of the thyroid, probably caused by a virus.

Subacute thyroiditis usually begins suddenly. In this disorder, inflammation causes the thyroid gland to release excessive amounts of thyroid hormones, resulting in hyperthyroidism, almost always followed by transient hypothyroidism and finally normal thyroid function.

Subacute thyroiditis often follows a viral illness and begins with what many people call a sore throat but actually proves to be neck pain localized to the thyroid. Many people with subacute thyroiditis feel extremely tired. The thyroid gland becomes increasingly tender, and the person usually develops a low-grade fever (99 to 101° F [37 to 38º C]). The pain may shift from one side of the neck to the other, spread to the jaw and ears, and hurt more when the head is turned or when the person swallows. Subacute thyroiditis is often mistaken at first for a dental problem or a throat or ear infection.

Most people recover completely from this type of thyroiditis. Generally the thyroiditis resolves by itself within a few months, but sometimes it comes back or, more rarely, damages enough of the thyroid gland to cause permanent hypothyroidism.

Aspirin or other nonsteroidal anti-inflammatory drugs (NSAIDs) can relieve the pain and inflammation. In severe cases, doctors may recommend corticosteroids, such as prednisone, which are gradually decreased over 6 to 8 weeks. When corticosteroids are discontinued abruptly or too early, symptoms often return in full force. When symptoms of hyperthyroidism are severe, a beta-blocker may be recommended.

Last full review/revision May 2012 by Jerome M. Hershman, MD