Sarcoidosis: a comprehensive review and update for the dermatologist: part I. Cutaneous disease.

Sarcoidosis is a common systemic, noncaseating granulomatous disease of unknown etiology. The development of sarcoidosis has been associated with a number of environmental factors and genes. Cutaneous sarcoidosis, the "great imitator," can baffle clinicians because of its diverse manifestations and its ability to resemble both common and rare cutaneous diseases. Depending on the type, location, and distribution of the lesions, treatment can prevent functional impairment, symptomatic distress, scarring, and disfigurement. Numerous therapeutic options are available for the treatment of cutaneous sarcoidosis, but there are few well designed trials to guide practitioners on evidence-based, best practice management. In part I, we review the current knowledge and advances in the epidemiology, etiology, pathogenesis, and genetics of sarcoidosis, discuss the heterogeneous manifestations of cutaneous sarcoidosis, and provide a guide for treatment of cutaneous sarcoidosis.