Sarcoidosis is an immune system disorder that can attack any organ of the body. However, it most frequently starts in the lungs and lymph nodes, particularly those in the chest cavity. Sarcoidosis is characterized by the presence of small (microscopic) areas or lumps of inflammed cells called granulomas. The granulomas can grow and form larger clusters within an organ and may affect the function of the organ. Granulomas can be found inside the body, for example, on the walls of the bronchi and bronchioles (breathing tubes) in the lungs. They can also appear as sores on the skin. Sarcoidosis also affects the eyes and liver and less often, the spleen, nerves, heart, brain, salivary glands, tear glands, bones and joints.
Sarcoidosis causes a variety of symptoms or no symptoms at all. It is not contagious. Patients suffering from pulmonary sarcoidosis may have a dry cough, shortness of breath and chest pain. There also can be fatigue, weakness and weight loss. For those cases where the disease appears outside the lungs, symptoms can include general discomfort, loss of appetite and/or loss of weight, fever, painful joints, scaly rashes, and bloodshot eyes.
The diagnosis of sarcoidosis is based on the patient's medical history, physical examination, laboratory tests, lung function studies, and chest x-ray. The diagnosis is confirmed by eliminating other diseases having similar symptoms and performing a biopsy on any of the affected organs. Sarcoidosis is not a type of cancer.
Sarcoidosis usually occurs between the ages of 20 to 40 years. People of African and Scandinavian descent are more likely to have sarcoidosis. It affects both men and women but studies show it is more likely to occur in women. The incidence of the disease in the United States is 1 to 40 cases per 100,000 people; 20 cases per 100,000 in the United Kingdom and 3 to 50 cases per 100,000 in Europe.
Many patients recover completely without treatment. When therapy is recommended, drugs called corticosteroids are used to reduce the inflammation.
The link between sarcoidosis and work has not been established. Some studies show that residents of rural areas have an increased risk of developing sarcoidosis. Some researchers propose that environmental factors may be associated with the disease but no studies to date support this hypothesis.
One study also noted that people living close to granite rocks with high beryllium content had a high incidence of sarcoidosis. Beryllium lung disease is very similar in its clinical and radiographic appearance to sarcoidosis but the chemical element has not yet been identified as the direct cause of the disease.
Other studies considered occupational risk factors by comparing workers of the lumbering industry who are thought to have a high incidence of sarcoidosis with other workers not in this industry but no difference in the incidence of sarcoidosis was found.
Several attempts have been made to link bacteria and viruses with sarcoidosis but none of these microorganisms were found to have a relation with the disease. Other factors like genetics, allergies and smoking have been investigated but no positive results have been found.
Even though studies have been carried our worldwide for many years, sarcoidosis is still a disease of unknown cause.
Document last updated on January 2, 2009