Sarcoidosis.

Sarcoidosis is a disease characterized by noncaseating granulomatous infiltration of 1 or more organs. In North America, after the lungs and thoracic lymph nodes, the skin is the next most commonly involved organ. Data from multiple studies indicate a coaction between genetic and environmental factors in immunologically susceptible hosts. The disease's many clinical manifestations and course vary greatly and are influenced by race, ethnicity, and gender. In the skin, the lesions of sarcoidosis are classified as specific when noncaseating granulomas are present, and nonspecific when there is an inflammatory reaction pattern devoid of granulomas.