Sarcoidosis

Sarcoidosis affects people of all racial and ethnic groups and occurs at any age, although usually before the age of 50 years. The incidence of sarcoidosis varies widely throughout the world, probably because of differences in environmental exposures, case-surveillance methods, and predisposing HLA alleles, along with other genetic factors. This article summarizes advances in our understanding of sarcoidosis and addresses pitfalls in its diagnosis and treatment.