Physiology

Sarcoidosis:

In 1869, Jonathon Hutchinson, a surgeon-dermatologist, identified the first case of sarcoidosis at King’s College Hospital (London, UK). He described a 58-year-old coal-wharf worker with purple, symmetrical skin plaques on the legs and hands that had gradually developed over the preceding two years. The lesions were neither tender nor painful.

Sarcoidosis seems to be caused by an immune reaction to an infection or some other trigger (called an antigen, which may be from one's environment) that continues even after the initial infection or other antigen is cleared from the body.

Sarcoidosis involves inflammation that produces tiny lumps of cells in various organs in your body. The lumps are called granulomas. Granulomas are immune cells within our tissues that are programmed to fight infection and control inflammation. They are very small and can be seen only with a microscope. These tiny granulomas can grow and clump together, forming larger granulomas that interfere with normal body functions such as breathing.

A multi-organ disease, sarcoidosis may affect a range of systems, including the nervous system, musculoskeletal system, lymph glands, lungs, skin, liver, spleen, eyes, heart, brain, and kidneys. In some cases inflamed granulomas may interfere with the functioning of an organ.

Granulomas in the lungs can cause narrowing of the airways and inflammation and scarring of lung tissue.

http://www.nyc.gov/html/doh/wtc/downloads/pdf/wtc/SarcoidosisFS.pdf

http://www.uptodate.com/contents/sarcoidosis-beyond-the-basics

http://www.mountsinai.org/patient-care/service-areas/lung-diseases-and-surgery/areas-of-care/sarcoidosis-program/what-is-sarcoidosis