sarcoid

Sarcoid, commonly used to refer to sarcoidosis, is a chronic systemic inflammatory disease characterized by the formation of noncaseating granulomas in affected tissues. The exact cause is unknown, but it is thought to result from an interplay of genetic susceptibility and environmental triggers that lead to an exaggerated immune response. The lungs and intrathoracic lymph nodes are most commonly involved, but skin, eyes, liver, heart, nervous system, and other organs can be affected.

Many cases are asymptomatic and discovered on imaging or routine tests. When symptoms occur, they may include cough, dyspnea, chest pain, fatigue, fever, and weight loss. Skin lesions such as erythema nodosum or lupus pernio, eye inflammation (uveitis), and systemic symptoms are also seen. Diagnosis requires compatible clinical and radiographic findings and histologic confirmation of noncaseating granulomas, with other causes (notably infections such as tuberculosis) excluded. Serum ACE levels and calcium metabolism may be affected, but are not specific.

Treatment depends on organ involvement and severity. Mild disease may resolve without treatment. Corticosteroids are the first-line therapy for significant symptoms or organ threats. Immunosuppressants such as methotrexate, azathioprine, or mycophenolate may be used for chronic or refractory disease. Hydroxychloroquine can help skin manifestations; anti-TNF agents are used in selected cases. Ongoing monitoring for organ involvement, including heart and eyes, is important.

Prognosis is generally favorable, with many patients experiencing remission within a few years, but relapses occur and some develop chronic disease. Cardiac, neurosarcoidosis, or ocular complications can carry greater risk. Epidemiology varies by population; sarcoidosis is more common among people of African descent and in Northern Europe, typically presenting in young adults.