Approximately 90% of pts are women, usually of child-bearing age; more common in blacks than whites. Course of disease is often characterized by periods of exacerbation and relative quiescence. May involve virtually any organ system and have a wide range of disease severity. Common features include:

• Constitutional: fatigue, fever, malaise, weight loss
• Cutaneous: rashes (especially malar “butterfly” rash), photosensitivity, vasculitis, alopecia, oral ulcers
• Arthritis: inflammatory, symmetric, nonerosive
• Hematologic: anemia (may be hemolytic), neutropenia, thrombocytopenia, lymphadenopathy, splenomegaly, venous or arterial thrombosis
• Cardiopulmonary: pleuritis, pericarditis, myocarditis, endocarditis. Pts are also at increased risk of myocardial infarction usually due to accelerated atherosclerosis.
• Nephritis: classification is primarily histologic (Table 378-2, p. 2127, in HPIM-19)
• GI: peritonitis, vasculitis
• Neurologic: organic brain syndromes, seizures, psychosis, cerebritis