In sarcoidosis, the immune system attacks tissues and leaves little scars called granulomas. Granulomas can affect nearly every organ in the body, but often they're confined to just the lungs. Sarcoidosis is rare. Only about one or two people out of 10,000 have it in the United States. It tends to start before age 40, so if you are older than 40, the small chance that you will get sarcoidosis gets even smaller.
Despite more than 50 years of research, the cause is still a mystery. Many experts believe that there are multiple causes, which all contribute to triggering the damaging immune system response that leads to the granulomas. Infectious agents—bacteria or viruses of some kind—are among the suspects, but so far none has been identified as a cause.
Sarcoidosis can't be cured. Treatment is usually reserved for people experiencing symptoms, and drugs like prednisone and methotrexate that dampen the immune response are often quite effective. That's the good news, but the better news is that sarcoidosis is one of the many diseases that you will probably never get.
Find out more about this book:Harvard Medical School The Truth About Your Immune System