Systemic lupus erythematosus (SLE) is an autoimmune disorder that affects many parts of the body. An autoimmune disorder is a condition in which the body creates antibodies against its own tissues. Antibodies are cells that usually fight off infections or foreign material that enters the body. In the case of SLE, the antibodies attack the body's own tissues. Drug-induced lupus erythematosus causes a similar condition, but it is caused by a medicine.

What is going on in the body?

In a person with SLE, the body produces a number of "autoantibodies" that attack various parts of cells within the person's own body. These antibodies are deposited in different tissues and organs throughout the body. These deposits cause swelling and damage to blood vessels in many organs. The affected body parts include:

Occasionally, certain medicines can cause drug-induced lupus with the same symptoms.

What are the causes and risks of the condition?

Procainamide and hydralazine are most commonly associated with drug-induced lupus. Procainamide is used to treat arrhythmias, and hydralazine is used to treat high blood pressure. Other medicines that can cause drug-induced lupus include:

The symptoms of lupus may not appear at low doses of these medicines. However, as the dose increases, the lupus-like syndrome may appear. Also, use of some of these medicines for long periods of time increases one's risk of developing the condition. With some of the medicines, however, the condition may develop anytime during therapy.

Many other medicines are suspected to cause lupus. However, the evidence is not as clear-cut as it is with the first list of medicines. Medicines that may cause lupus include: