A single provoking agent or disordered defense reactions triggered by various insults may be responsible, and genetic factors may be important. These granulomas may resolve completely or proceed to fibrosis. Although similar granulomas can occur in various infections, hypersensitivity reactions, pneumonia, and foreign body reactions, characteristic patterns of involvement indicate sarcoidosis. Symptoms and Signs Symptoms depend on the site of involvement and may be absent, slight, or severe. Fever, weight loss, and arthralgias may occur initially.
Persistent fever is common with liver involvement.
Organ function may be impaired by the active granulomatous disease or by secondary fibrosis. Cough and dyspnea may be minimal or absent. Erythema nodosum, often with fever and arthralgias, is commonly the presenting symptom in Europeans but less commonly in Americans. Lacrimal gland enlargement, conjunctival and eyelid infiltrations, and keratitis sicca occasionally are present. Acute periarticular ankle inflammation often occurs without cutaneous lesions and is often not recognized as a presentation of sarcoidosis.