There isn’t one clear cause of sarcoidosis. However, the condition may develop as a person’s immune system reacts to a substance inhaled through the air, such as a chemical or environmental toxin. Since it’s an immune-related condition, people with sarcoidosis may have an abnormal immune response. The condition occurs most often in people who are between the ages of 20 and 40, and women are more frequently diagnosed with sarcoidosis than men. There may be a genetic component to sarcoidosis, as having a family member with the condition increases your odds of developing the disease.