American Board of Internal Medicine (ABIM) Certification Practice Exam 2025 - Free ABIM Practice Questions and Study Guide

Löfgren syndrome is characterized by a specific triad of symptoms: acute arthritis, bilateral hilar lymphadenopathy, and erythema nodosum. This syndrome is considered a form of sarcoidosis, which is an inflammatory disease that can affect multiple organs, primarily the lungs and lymphatic system. The acute arthritis often presents as swollen and painful joints, and the bilateral hilar lymphadenopathy is a common radiological finding depicted in imaging studies, often discovered incidentally. Erythema nodosum appears as tender red nodules on the skin, typically on the lower legs, and is indicative of an underlying systemic process.

In the context of this syndrome, the combination of these symptoms is quite distinct and helps differentiate it from other conditions. For instance, while granulomatosis with polyangiitis (an autoimmune vasculitis) may present with arthritis and systemic symptoms, it does not typically cause hilar lymphadenopathy or erythema nodosum. Rheumatoid arthritis is primarily characterized by symmetrical joint involvement and does not commonly feature the other symptoms mentioned. Systemic lupus erythematosus has a diverse range of symptoms and while it can involve arthritis and skin lesions, it does not present with hilar lymphadenopathy as a defining