Sarcoidosis is an inflammatory disease that primarily affects the lungs, but can also involve other organs such as the skin, eyes, and lymph nodes. It is characterized by the formation of small clusters of immune cells called granulomas, which can disrupt normal organ function. The exact cause of sarcoidosis is unknown, but it may be related to an abnormal immune response to environmental factors or infections. Symptoms of sarcoidosis can vary widely and may include persistent cough, shortness of breath, fatigue, and skin rashes. Diagnosis typically involves imaging tests like chest X-rays, lung function tests, and sometimes a biopsy to confirm the presence of granulomas. Treatment may not be necessary for mild cases, but more severe instances may require medications such as corticosteroids.