Löfgren synrome is a type of acute sarcoidosis that is frequent in Scandinavian, Irish, African and Puerto Rican women. It is characterized by enlargement of the lymph nodes near the inner border of the lungs (called "hilar lymphadenopathy") as seen on x-ray, and tender red nodules (erythema nodosum) are classically present on the shins. It may also be accompanied by arthritis and fever.