Symptoms, Causes, and Treatment of Sarcoidosis.

Sarcoidosis is a heterogeneous, multisystem granulomatous disorder of unknown etiology that predominantly affects adults aged 20-60 years. Clinical presentation ranges from asymptomatic disease detected incidentally to progressive organ dysfunction. The lymphatic system, lungs, and skin are most commonly involved, although virtually any organ may be affected. Diagnosis remains challenging due to the absence of a pathognomonic test and significant overlap with infectious, autoimmune, and neoplastic conditions, necessitating careful evaluation to exclude alternative etiologies. Accordingly, sarcoidosis remains a diagnosis of exclusion, supported by compatible clinical and radiographic findings and histologic evidence of non-necrotizing granulomas. This review summarizes current understanding of sarcoidosis epidemiology, immunopathogenesis, and clinical manifestations, and provides a practical approach to diagnosis and management. It also highlights recent advances, including key clinical trials, emerging biomarkers, and novel therapeutic strategies. Finally, it addresses common clinical challenges and persistent knowledge gaps in the field. The goal is to inform clinicians with an updated framework to optimize care for patients with sarcoidosis.