While the cause of sarcoidosis is unknown, it is hypothesized that a combination of genetic and environmental factors contributes to its occurrence. Sarcoidosis has a world-wide distribution, and anyone can develop it. Sarcoidosis can affect people of every race, sex, and age; however, people of African, Scandinavian, Irish, Asian, German, and Puerto Rican descent appear to have a higher prevalence of the disease, and are more at risk.
Once considered a rare disease, it is now estimated that there are approximately 180,000 – 200,000 cases of sarcoidosis per year within the United States. The incidence of sarcoidosis ranges widely from one to forty cases per 100,000 people; the prevalence of sarcoidosis is ten times greater for African Americans than Caucasians.
Both men and women can be diagnosed with sarcoidosis, but it is more common in women, and often appears in patients between the ages of 20 and 40. Sarcoidosis is not believed to be contagious.
Familial, seasonal, and occupational clustering is common in sarcoidosis. If there is a genetic factor involved, and a person is exposed to an infection or environmental contaminant, it may trigger the immune system to overreact more intensely than normal, causing the person to develop the disease. People who are sensitive to dust or mold may be at a higher risk of developing sarcoidosis if they work in environments that contain dust or mold. There are cases of people who were exposed to beryllium in manufacturing settings, and contaminants at the World Trade Center during 9/11 who developed sarcoidosis. Stress and allergic reactions can also trigger sarcoidosis. A few common symptoms of sarcoidosis may include fever, enlarged lymph nodes, swollen or painful joints, and raised red bumps on the skin similar to hives.