Sarcoidosis is a multi system granulomatous disorder affecting predominantly young adults although may affect adults of any age. It is particularly likely to affect the respiratory tract where it may cause mediastinal lymph node enlargement , and granulomatous inflammation of alveoli (air sacs). In a minority of cases it may lead to progressive thickening and fibrosis of alveolar septa, and hence impaired gas exchange. Symptoms of sarcoidosis include cough, dyspnoea (shortness of breath) and occasionally chest pain. Other manifestations of sarcoidosis include granulomatous inflammation of the liver, cardiac conduction abnormalities, painful skin lesions (erythma nodosum), and eye disease (uveitis). Treatment is usually only provided where significant impairment is present. Standard treatment is based on the use of corticosteroids (prednisone or prednisolone).