Sarcoidosis. Organ involvement, diagnosis, current treatment

Sarcoidosis is characterized by the appearance of noncausating, epitheloid cell granulomas, primarily in skin and lung. Hereditary disposition is well known; additional infection-associated triggers play a role for the development of inflammation mediated by T helper (Th) 1 cells. Clinically, various disease courses can be observed that are characterized by the formation of skin papules at typical sites of the body which differ in their tendency to be associated with systemic organ involvement. Systemic disease without skin affections is also possible. The diagnosis is based on the typical clinical appearance, biopsy of affected tissue (e.g. skin, lung) and laboratory investigations. Additional systemic involvement needs to be excluded. In most cases, the disease is self-limited, but can also be life threatening due to organ fibrosis. The degree of (extra-) cutaneous involvement and level of discomfort are used to select the type of treatment, which ranges from topical immune suppressive agents to systemic therapy with corticosteroids. In nonresponders, additional modern immunosuppressive/immunomodulating therapeutic options are available.