However, they may be found anywhere, including the eyes, ears, bones, and even in the coverings around the brain and spinal cord. Although these granulomas are usually widespread, they are very small and can only be seen with the aid of the microscope. The cause of sarcoidosis is completely unknown. At one time pine pollen was thought to be the cause since many of the cases were found in people who lived near pine forests. The evidence for these and other agents as a cure remains unproved.
Sarcoidosis occurs in all ages and races and in both sexes.
It is not inherited and does not tend to run in families. In the United States sarcoidosis seems to be most common among black women, but the reason is entirely unknown. Many patients with sarcoidosis have no symptoms. The granulomas, hidden within the body's organs, are discovered only if carefully looked for. In recent years certain radiologic and blood tests have proven more specific for this condition, so that some patients are now presumptively diagnosed without resort to tissue biopsy.