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.
Genetics and Lupus
Your genes are the sets of instructions that tell your body how to work. Changes to your genes can sometimes lead to disease.
An international team of scientists has spotted a mutated version of a gene called toll-like receptor 7 (TLR7) that they suspect can cause lupus.
Normally, TLR7 helps the immune system (your body’s defenses) fight viruses. But the mutated version can cause the immune system to attack healthy cells.
The researchers discovered the TLR7 mutation in a Spanish girl named Gabriela. She was diagnosed with severe lupus at the age of 7.
Then, they used a gene-editing tool to introduce the mutation into mice to find out if the critters would get lupus. The mice carrying the mutation ended up developing a condition that mimicked severe autoimmune disease in people. This offers evidence that the mutated TLR7 causes lupus, one of the researchers says.
The researchers hope their findings eventually lead to new lupus treatments that are more effective and have fewer side effects.
Lupus also often runs in families. So if your parent, brother, or sister has lupus, you're a bit more likely (just between 1% and 5%) to get it than someone who doesn't have it in their family.
Certain racial and 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
- Native American
- Native Hawaiian
- Pacific Islander
Women and Lupus
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:
- Epstein-Barr virus, which causes mononucleosis
- Varicella-zoster virus, which causes chickenpox and 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 for high blood pressure
- Penicillamine for rheumatoid arthritis
- Procainamide for heart rhythm problems
- Quinidine for heart rhythm problems and malaria
You usually get better once you stop taking the drug that causes your lupus symptoms.
Other drugs aren’t a cause of lupus but can make lupus symptoms flare once you already have the disease. These include:
- Drugs that increase your sensitivity to the sun, such as sulfa drugs that treat bacterial infections and some tetracycline drugs
- Some antibiotics, such as penicillin, amoxicillin, ampicillin, and cloxacillin
- Para-aminobenzoic acid (PABA), which is often found in sunscreen but can also be used to treat skin disorders like scleroderma or dermatomyositis
- Cimetidine (Tagamet), a stomach acid reducer that helps treat stomach ulcers
- Golimumab, an immunosuppressive drug that treats conditions such as rheumatoid arthritis, psoriatic arthritis, ulcerative colitis, and ankylosing spondylitis
- Hydralazine, a drug that treats high blood pressure
- Hydrochlorothiazide, a diuretic drug that helps your body get rid of fluids.
- Omeprazole, a heartburn medication
- Terbinafine, an antifungal you use to treat athlete’s foot, jock itch, or fungal infections on your nails and scalp
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:
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.
What You Can Do
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 shingles, doesn’t mean you’ll get lupus, too. If you're concerned about your risk, or have already noticed symptoms, talk to your doctor.