Systemic lupus erythematosus (SLE or lupus, ) is a chronic autoimmune disease that can be fatal, though with recent medical advances, fatalities are becoming increasingly rare. As with other autoimmune diseases, the immune system attacks the body's cells and tissue, resulting in inflammation and tissue damage. SLE can affect any part of the body, but most often harms the heart, joints, skin, lungs, blood vessels, liver, kidneys, and nervous system. The course of the disease is unpredictable, with periods of illness (called flares) alternating with remissions. Lupus can occur at any age, and is most common in women, particularly of non-European descent. Lupus is treatable symptomatically, mainly with corticosteroids and immunosuppressants, though there is currently no cure. Survival in patients with SLE in the United States, Canada, and Europe is approximately 95% at 5 years, 90% at 10 years, and 78% at 20 years.

Classification

• Drug-induced lupus erythematosus, a drug-induced form of SLE; this type of lupus can occur equally in either sex.
• Lupus nephritis, an inflammation of the kidneys caused by SLE.
• Discoid lupus erythematosus, a skin disorder that causes a red, raised rash on the face and scalp. Discoid lupus occasionally (1–5%) develops into SLE.
• Subacute cutaneous lupus erythematosus, which causes nonscarring skin lesions on patches of skin exposed to sunlight.
• Neonatal lupus, a rare disease affecting babies born to women with SLE, Sjögren's syndrome, or sometimes no autoimmune disorder. It is theorized that maternal antibodies attack the fetus, causing skin rash; liver problems; low blood counts, which gradually fade; and heart block, leading to bradycardia.

Signs and symptoms

SLE is one of several diseases known as "the great imitators" because its symptoms vary so widely, it often mimics or is mistaken for other illnesses because the symptoms come and go unpredictably. Diagnosis can be elusive, with patients sometimes suffering unexplained symptoms and untreated SLE for years. Common initial and chronic complaints are fever, malaise, joint pains, myalgias, fatigue and temporary loss of cognitive abilities. Because they are so often seen with other diseases, these signs and symptoms are not part of the diagnostic criteria for SLE. When occurring in conjunction with other signs and symptoms (see below), however, they are considered suggestive.

Common symptoms explained

Dermatological manifestations: As many as 30% of patients present with some dermatological symptoms (and 65% suffer such symptoms at some point), with 30% to 50% suffering from the classic malar rash (or butterfly rash) associated with the disease. Patients may present with discoid lupus (thick, red scaly patches on the skin). Alopecia; mouth, nasal, and vaginal ulcers; and lesions on the skin are also possible manifestations.