Sarcoidosis

Sarcoidosis is a multisystem inflammatory disease characterized by the formation of granulomas — small clusters of immune cells — in one or more organs. The lungs and thoracic lymph nodes are involved in more than 90 percent of cases, but granulomas can develop in the skin, eyes, heart, liver, kidneys, nervous system, and bones. The underlying cause is unknown, but current evidence suggests an aberrant immune response to environmental antigens (possibly occupational exposures, infectious triggers) in genetically susceptible individuals. The disease course ranges from asymptomatic spontaneous resolution to progressive, organ-damaging chronic disease.

• Persistent dry cough and shortness of breath (pulmonary)
• Fatigue — often profound, even when other symptoms are mild
• Fever and night sweats
• Swollen lymph nodes (especially mediastinal, visible on chest imaging)
• Skin lesions: lupus pernio (violaceous nodules on the nose and cheeks, more common in Black patients), subcutaneous nodules, or erythema nodosum
• Eye redness, pain, or blurred vision (uveitis — requires prompt evaluation)
• Irregular heartbeat or palpitations (cardiac sarcoidosis)
• Neurological symptoms: facial palsy, weakness, headache (neurosarcoidosis)

There is no population-screening test for sarcoidosis. Diagnosis requires clinical and radiographic findings consistent with sarcoidosis plus pathological confirmation of granulomas (usually by tissue biopsy) after excluding other causes of granulomatous disease (tuberculosis, fungal infection). ACE (angiotensin converting enzyme) levels are neither sensitive nor specific enough for diagnosis but may be useful for monitoring disease activity over time. A comprehensive organ survey at initial diagnosis — chest CT, ECG, echocardiogram, ophthalmology exam, metabolic panel, and urinalysis — is recommended to assess extent of disease before treatment decisions.

Not all sarcoidosis requires treatment: pulmonary Stage I and Stage II with mild symptoms often resolves spontaneously. For progressive or organ-threatening disease, systemic corticosteroids (prednisone) are the first-line treatment. Steroid-sparing immunosuppressants — methotrexate, azathioprine, and hydroxychloroquine (for skin and fatigue) — are used for chronic management to limit steroid side effects. For refractory or severe disease, anti-TNF agents including infliximab have substantial evidence for benefit, particularly in pulmonary and cutaneous sarcoidosis. Cardiac sarcoidosis may require implantable cardioverter-defibrillator (ICD) placement. Pulmonary function testing (spirometry and DLCO) at diagnosis and every 3–6 months guides treatment decisions.