Sarcoidosis is a chronic inflammatory disease that usually affects the lungs and lymph nodes but can also affect other organs in the body. The cause of sarcoidosis is unknown, but it is believed to be triggered by an immune system response to an unknown substance. Symptoms of sarcoidosis vary depending on which organs are affected but may include coughing, shortness of breath, fatigue, skin lesions, and swollen lymph nodes. Diagnosis of sarcoidosis is made through a combination of physical examination, imaging tests, and laboratory tests. Treatment for sarcoidosis is typically based on the severity of symptoms and the organs affected. Treatment may include corticosteroid medications, immunosuppressants, and oxygen therapy. In some cases, surgery may be necessary.