Lupus is a chronic inflammatory disease marked by its effect on various parts of the body, including the joints, skin, blood, and kidneys. It is a condition in which the body's immune system attacks its own cells and tissues, resulting in pain, inflammation, and often damage to organs. For many people, the disease is mild and affects only a few organs. For others, however, the disease can be severe and even life threatening.

Lupus involves the immune system. The immune system makes antibodies that work to protect the body against foreign substances like viruses and bacteria. Such foreign bodies are called antigens.

When a person has lupus, his or her body is unable to determine the difference between antigens and the individual's cells and body tissues. As such, the immune system creates antibodies against the individual's own tissues. These antibodies are called autoantibodies.

When a person has lupus, autoantibodies react with cells and tissues to form immune complexes. These immune complexes become concentrated in the body. It is this concentration or build-up within body tissues that causes pain, inflammation, and damage.

There are four types of lupus. The first type, discoid lupus, affects the skin. It is characterized by a rash that may appear on the face, neck, or scalp. Individuals with this condition may also experience mouth or nose ulcers, as well as photosensitivity. Discoid lupus is diagnosed by performing a biopsy on the rash.

Systemic lupus is usually more severe than the discoid type, affecting nearly any organ or system of the body. For example, the disease can affect the skin, blood, nervous system, kidneys, heart, joints, and lungs. Some individuals with the disease have only one or two organs or tissues affected, while others may have many affected organs, systems, or tissues.

Systemic lupus may include periods of remission as well as periods of activity. Periods of activity are often referred to as flares. There is no single diagnostic test for the systemic form of the disease. A careful review of the patient's medical history is used, along with the results of various tests, to diagnose the condition.

Drug-induced lupus is caused by the use of certain drugs. It is characterized by symptoms similar to those caused by the systemic form of the disease. Hydralazine and procainamide are the two drugs most frequently connected with the disorder. Only a very small number of people taking these drugs develop the condition and the symptoms generally disappear upon discontinuing the medication.

The last type of lupus, neonatal lupus, occurs quite infrequently. Neonatal lupus affects newborns born to women who have systemic lupus. Their symptoms include heart defects, skin problems or problems with the liver.

Depending on the type of lupus, a wide range of symptoms may be experienced, from rashes, hair loss, and achy, swollen joints to fever, anemia, and abnormal blood clotting. Though the disease can affect many parts of the body, individuals usually experience symptoms in only a few organs. There is no known cure for lupus. However, medication and preventative-care treatments can help to minimize symptoms.