Sarcoidosis is a multisystemic inflammatory disorder of unknown etiology in which abnormal collections of chronic inflammatory cells (granulomas) form nodules in multiple organs. Sarcoidosis can affect any organ but mostly the disease starts in the lungs, skin, and/or lymph nodes (in the chest). The disease also often affects the eyes and the liver. Although less common, sarcoidosis can affect the heart and brain, leading to serious complications.

Sarcoidosis most commonly affects young adults and occurs throughout the world in all races with an average incidence of 16.5 per 100,000 in men and 19 per 100,000 in women.

Diagnosis of sarcoidosis is difficult because there is no known genetic cause or unique symptom. Often it's discovered when an x-ray of the chest reveals the characteristic swollen lymph nodes or shadowing in the lungs. Examining a sample of tissue taken from affected skin or lung under the microscope is an accurate way of confirming the diagnosis. Since the lungs are commonly affected, tests to assess lung function are usually performed. Sarcoidosis can also cause the level of calcium in the blood to rise, which may also be measured.

Sarcoidosis may be asymptomatic or chronic. The majority (~80%) of patients do not require therapy because the condition resolves spontaneously after a few years. In 10% the disease slowly gets worse over time and in 2% it proves fatal. Currently, there's no cure for sarcoidosis. Relief from symptoms can be found with anti-inflammatory painkillers, and steroids can also prove extremely effective. In more severe cases, immunosuppressive drugs such as methotrexate are used. Newer drugs such as infliximab may also be prescribed.

Recent publications describe chitotriosidase level in serum and or bronchoalveolar lavage (BAL) to be a useful marker for monitoring disease activity in sarcoidosis.

R.G. Boot et al. Plasma chitotriosidase and CCL18 as surrogate markers for granulomatous macrophages in sarcoidosis. Clin Chim Acta. 2010 Jan;411(1-2):31-6.

J. Brunner et al. Chitotriosidase as a marker of disease activity in sarcoidosis. Rheumatol Int 2007;27:1185–1186.

E. Bargagli et al. Human Chitotriosidase: A Potential New Marker of Sarcoidosis Severity. Respiration 2008;76:234–238