When enlargement of lymph glands in the center of the lungs is seen on x-ray, sarcoidosis may be suspected. To confirm the diagnosis, a biopsy is usually performed on any of the affected organs or from material in a granuloma on the skin. About 50 percent of sarcoidosis patients improve spontaneously. The disease is fatal in less than 5 percent of patients. In between the two extremes, patients have mild to severe sarcoidosis, with various degrees of impairment, or none at all.
Sarcoidosis is found throughout the world within almost all races and ages and in both sexes.
However, it is most common among American blacks and northern European whites. Sarcoidosis is mainly a disease of young adults, patients between the ages of 20 and 40, although a few persons past 60 have been known to have it. In the United States, a higher percentage of blacks than whites have sarcoidosis, and the disease is usually more serious in blacks. This is a big part of the mystery. No one knows.