May 2007

Does having autoimmune thyroiditis make me more likely to have other autoimmune diseases (like hepatitis?). 

Autoimmune diseases occur when a person’s immune system attacks his or her own body. Many different organs and tissues can be affected by autoimmune disease, including the endocrine glands, nerves, muscles, skin, blood cells, and the digestive system.

Autoimmune diseases affect women more frequently than men, and can occur at any age. Autoimmune thyroid disease is relatively common. Anti-thyroid antibodies are present in up to 20% of the U.S. population. Autoimmune thyroiditis occurs when thyroid cells are damaged by the immune system. It is probably due to a combination of environmental and genetic factors [see brochure on hypothyroidism].

Autoimmune diseases sometimes occur in clusters. For example, polyglandular autoimmune syndrome type 2 is a relatively rare condition in which patients with autoimmune adrenal insufficiency (Addison’s disease) may also have autoimmune thyroid disease and/or type 1 diabetes. Autoimmune thyroiditis can also occasionally be associated with other autoimmune diseases such as autoimmune hepatitis, rheumatoid arthritis, or celiac sprue disease. In general, these other autoimmune syndromes are much less common than autoimmune thyroid disease. Therefore, the likelihood that someone with a rare autoimmune disease such as autoimmune hepatitis will also have thyroid disease is relatively high, but the risk that someone with thyroid disease will also have autoimmune hepatitis is relatively low.

In general, patients with one autoimmune disease have a slightly higher risk of having another autoimmune disease.  However, the vast majority of patients with autoimmune thyroiditis will develop only the thyroiditis.