context: Doctors don't know exactly what causes lupus. They think genetics, hormones, and your environment may be involved. Your body's immune system protects you from bacteria, viruses, and other foreign invaders that can make you sick. But if you have lupus, your immune system also mistakenly attacks and damages your body's own tissues, too. Diseases that do this are called autoimmune diseases. You could be born with a gene that makes you more likely to get lupus. Then you might be exposed to something in your environment, and that triggers the disease. But even if both of these things come together, that still doesn't mean you'll get lupus. That's why it's so hard for doctors to figure out what causes it. What researchers do know is there are certain things that make you more likely to get it, including your heredity, gender, race, and even previous illnesses. Your genes are the sets of instructions that tell your body how to work. Changes to your genes can sometimes lead to disease. Scientists haven't found any single gene that causes lupus. Yet people with lupus are more likely to have changes to the genes that help their immune system recognize and respond to viruses and other germs. Lupus also often runs in families. So if your parent, brother, or sister has lupus, you're a bit more likely (just between 5% and 13%) to get it than someone who doesn't have it in their family. Certain ethnic groups share common genes that may make them more likely to get lupus. Your chances are higher of getting the disease if you are: African- American Asian Hispanic/ Latino Native American Native Hawaiian Pacific Islander Doctors think the hormone estrogen might play a part in lupus because 9 out of 10 people who have it are female. Men and women both make estrogen, but women make much more. What's the connection? Research shows that estrogen helps make women's immune systems stronger than men's, so the hormone could also trigger lupus or make it worse. Some women with lupus also get symptom flare-ups around their period or during pregnancy when estrogen levels are higher. But this doesn't prove that estrogen causes lupus. Most researchers believe that just having genes that make you more likely to get lupus isn't enough. You also have to come in contact with something in the environment, such as a virus, to get the disease. These triggers may include: Sunlight. Ultraviolet, or UV, light from the sun damages your cells. That's why you get sunburn. But in some people, the immune system attacks the sunburned, or damaged, cells. And UV light not only seems to trigger lupus, it also appears to make symptoms worse. When people with lupus are exposed to UV rays, they tend to get joint pain and feel fatigued. Infections. Usually when you get sick, your immune system fights off the virus and then stops. But in people with lupus, the immune system keeps attacking. Doctors don't know why. Viruses that have been linked to lupus include: Cytomegalovirus Epstein- Barr virus, which causes mononucleosis Herpes zoster virus, which causes shingles Medications. Certain drugs can make your immune system overreact and cause what's called drug-induced lupus. It usually doesn't last long. Nearly 50 different drugs have been linked to lupus, including medicines to treat heart disease, thyroid disease, infections, and high blood pressure. The drugs most likely to cause lupus are: Hydralazine ( Apresoline) for high blood pressure Isoniazid, minocycline for infections Procainamide ( Pronestyl) for heart rhythm problems Quinidine ( Quinaglute) for heart rhythm problems and malaria Toxins. Research shows that being around certain chemicals -- including cigarette smoke, mercury, and silica -- could be linked to lupus. But nobody has been able to prove a direct connection. If you work in an industry where you're exposed to mercury and silica, talk to your doctor. And it's always a good idea to quit smoking. Stress. Some people say that a stressful event happened right before their first lupus flare. Although doctors haven't proven that stress is a direct cause of lupus, it's known to trigger flare-ups in people who already have the disease. Stressful events that can make symptoms worse include: A death in the family Divorce Extreme fatigue Injury Pregnancy/childbirth Surgery Everyday stresses -- things like traffic or conflicts at work or in a relationship -- are less dramatic. But over time, if they build up, they can take a toll, too. So you'll want to have a good way to handle those day-to-day challenges. Exercise is one way to burn off stress. So are spending time with friends, doing something you enjoy, and meditating or praying. If you're going through a hard time, or need more ideas to tame your stress, consider talking with a counselor. Even a few sessions can make a difference. Although we know the things that are linked to lupus, it's important to remember that researchers have not been able to prove that they directly cause the disease. Just because your brother or sister has lupus, or you've had herpes zoster virus, that doesn't mean you'll get lupus, too. If you're concerned about your risk, or have already noticed symptoms, talk to your doctor.