[Sarcoidosis : Dermatological view of a rare multisystem disease]

Sarcoidosis is a rare multisystem inflammatory disease of largely unknown etiology. While pulmonary sarcoidosis is the most abundant organ manifestation, involvement of the skin that occurs in up to 30% of patients is the most common extrapulmonary presentation of the disease. Dermatologists therefore play an important role not only for establishing the diagnosis and delineating it from potential differential diagnoses but also for the interdisciplinary care of the patient. The clinical presentation of skin sarcoidosis is manifold, which occasionally aggravates making the final diagnosis. Specific skin lesions (with granulomas) and nonspecific skin manifestations (without granulomas) can be differentiated. Since a variety of organ systems can be affected, multidisciplinary cooperation is mandatory. Therapy of sarcoidosis is difficult; evidence-based studies and therapy guidelines are widely lacking. Our review intends to outline the characteristic clinical presentations of cutaneous sarcoidosis, describe the diagnostic approach and how to assure or exclude extracutaneous manifestations of sarcoidosis, and suggest a therapy algorithm for the treatment of skin sarcoidosis.