Systemic lupus erythematosus, commonly known as lupus, is an autoimmune disease. The immune system mistakenly attacks connective tissue in the body, injuring and sometimes destroying vital organs such as the joints, kidneys, brain, and heart.

The word "lupus" is Latin for wolf. Many people with this condition developed a rash on the face over the bridge of the nose and on the cheeks below the eyes that looks like the facial markings of a wolf.

Lupus affects several hundred thousand people in the United States. It strikes women more often than men, and blacks more often than whites.

Symptoms of lupus

Symptoms of lupus vary, depending on which tissues have been attacked and to what degree. Early symptoms of lupus are nonspecific, meaning they could be caused by a number of conditions:

• fever
• fatigue
• aches and pains
• loss of appetite
• weight loss
• nausea
• painful, aching joints and muscles
• swelling that causes discomfort and sometimes permanent joint damage
• abnormal sensitivity to sunlight
• mouth ulcers
• hair loss
• a butterfly-shaped rash across the bridge of the nose and upper cheeks on both sides of the face.

Lupus symptoms can flare up at any time. They are often triggered by sunlight, emotional stress, fatigue, or other factors.

The most severe complications of lupus involve damage by the immune system to major organs, especially the kidneys, lungs, heart, and brain.

Diagnosing lupus

Because the symptoms of lupus are like those of many other disorders, and the fact that they come and go, lupus can be difficult to diagnose. One study found that it took an average of eight years for people with lupus to get a definitive diagnosis.

One potentially helpful blood test is for abnormal antibodies called antinuclear antibodies. These antibodies are present in the majority of people who have lupus—but they are also present in people who have other conditions and up to 30% of healthy people have low levels of them. So having antinuclear antibodies doesn't necessarily mean you have lupus. But not having them is strong evidence that you do not have lupus.

Treating lupus

Treatment of lupus is individualized to an individual's circumstances and directed by the symptoms and signs of his or her illness. Medications used to treat lupus include:

• nonsteroidal anti-inflammatory drugs such as ibuprofen (Advil, Motrin, generic) or naproxen (Aleve, Naprosyn, generic)
• antimalarial drugs such as hydroxychloroquine (Plaquenil) or chloroquine (Aralen). People with lupus who take antimalarial medications have less active disease and less organ damage over time. Many experts now recommend antimalarial treatment for all people with lupus unless these medications cause side effects.
• corticosteroids, such as prednisone (Deltasone and others), hydrocortisone (Hydrocortin and others), methylprednisolone (Medrol), or dexamethasone (Decadron and others)
• immunosuppressive medications such as azathioprine (Imuran), cyclophosphamide (Cytoxan, Neosar), mycophenolate mofetil (CellCept),
• monoclonal antibodies, such as belimumab and rituximab (Rituxan). Belimumab is the first and only drug specifically developed for and approved to treat lupus.
• methotrexate (Rheumatrex, Trexall)
• anticoagulants such as warfarin (Coumadin), dabigatran (Pradaxa), rivaroxaban (Xarelto, or apixaban (Eliquis) are often taken by people with lupus to prevent potentially dangerous clots from forming in the bloodstream.