Löfgren’s syndrome is an acute form of sarcoidosis, a multisystem inflammatory disorder characterized by noncaseating granulomas. It typically presents with a classic triad of symptoms: erythema nodosum (painful, red nodules usually on the shins), bilateral hilar lymphadenopathy (enlarged lymph nodes in the chest seen on imaging), and polyarthritis or polyarthralgia (joint pain or inflammation, often affecting the ankles, knees, wrists, or elbows). Fever and fatigue may also accompany these symptoms, and uveitis occurs in some cases.

Causes

The exact cause of Löfgren’s syndrome, like sarcoidosis, is unknown. It is thought to involve a combination of genetic predisposition and environmental triggers, such as allergens, viruses, bacteria, or other antigens. The condition is strongly associated with the HLA-DRB1*03 allele, which is linked to a favorable prognosis. It may result from an exaggerated immune response involving activated macrophages and CD4 T-lymphocytes, leading to granuloma formation.

Connection to Secondary Raynaud’s Phenomenon

Löfgren’s syndrome itself is not a direct cause of secondary Raynaud’s phenomenon. However, sarcoidosis, the underlying condition, can occasionally be associated with secondary Raynaud’s due to:

• Vascular involvement: Sarcoidosis may cause granulomatous inflammation or vasculitis, affecting blood vessels and potentially leading to vasospasm characteristic of Raynaud’s.
• Autoimmune overlap: Sarcoidosis can coexist with other autoimmune diseases (e.g., systemic lupus erythematosus or scleroderma), which are known causes of secondary Raynaud’s.
• Nerve dysfunction: Rarely, sarcoidosis-related neuropathy may affect vascular control, contributing to Raynaud’s-like symptoms.

However, Raynaud’s is not a common feature of Löfgren’s syndrome specifically, and studies rarely report it in this context. If Raynaud’s is present, it would more likely be linked to broader sarcoidosis complications or a coexisting condition. In the case described in, the patient explicitly denied Raynaud’s phenomenon, supporting its rarity in Löfgren’s syndrome.

Key Points

• Demographics: Löfgren’s syndrome is more common in women, particularly those of Scandinavian, Irish, African, or Puerto Rican descent, and typically affects younger adults (median age ~37).
• Prognosis: It has an excellent prognosis, with >80–90% of cases resolving within 6 months to 2 years, often spontaneously. The HLA-DRB1*03 allele is associated with near-complete resolution.
• Diagnosis: The triad of erythema nodosum, bilateral hilar lymphadenopathy, and arthritis has ~95% specificity for sarcoidosis, often allowing diagnosis without biopsy. Chest X-rays or CT scans confirm lymphadenopathy, and skin biopsy may verify erythema nodosum.
• Treatment: Symptomatic management with NSAIDs is usually sufficient. Severe cases may require corticosteroids (e.g., prednisone) or, rarely, disease-modifying antirheumatic drugs (DMARDs) like methotrexate.

If Raynaud’s phenomenon is observed alongside Löfgren’s syndrome, clinicians should investigate for other autoimmune or vascular conditions, as sarcoidosis alone is an uncommon cause. Always consult a healthcare provider for personalized evaluation and management.

Disclaimer: owerl is not a doctor; please consult one.