What Is Lupus—And 9 Everyday Things That Trigger It

The lowdown on this difficult-to-diagnose autoimmune disease—and what you can do to minimize its potentially damaging effects on your body.

knee painAnut21ng Photo/Shutterstock

What is lupus?

Lupus is an autoimmune disease that causes the body’s immune system to attack its own organs and tissues. “What is lupus” is a more difficult question than you might think to answer for both doctors and patients, since the symptoms tend to be vague and mimic other illnesses; however, inflammation always plays a role. If you have systemic lupus erythematosus (SLE), inflammation can target everything from your skin and joints to your kidneys, heart, lungs, and brain, putting you at a greater risk for renal problems, heart disease, breathing difficulties, pregnancy complications, and more.

Some telltale symptoms of lupus include fatigue; joint pain; fever; photosensitivity (sensitivity to the sun); and rashes, sometimes including a butterfly-shaped rash on the nose and cheeks. Approximately 1.5 million Americans have lupus; women—especially women of color—make up the overwhelming majority of patients. So, when should you get checked out? “If someone is experiencing arthritis pains that last more than several weeks, fatigue, rashes, and abnormal sun reactions, they should see their doctor,” says Fotios Koumpouras, MD, a Yale Medicine rheumatologist and director of the Lupus Program. “Systemic lupus is a complex disease, and no two patients are quite alike.” Lupus is one of the under-diagnosed diseases doctors often miss.

What causes lupus?

Experts don’t know for sure what causes lupus, but they believe that a combination of genetic, hormonal, and environmental factors are at play. For example, while more than 50 genes have been linked to lupus, people can have those genes and yet never develop the condition; another factor is likely needed to trigger the disease. Dr. Koumpouras stresses the importance of controlling lupus early so that you can help suppress “flares” of the disease and minimize damage to your body.


Photosensitivity is a common symptom of lupus—sunlight can cause a rash and other symptom flare-ups. One study published in the Journal of the American Academy of Dermatology found that 70 percent of people with skin lupus reported that their symptoms worsened after exposure to sunlight, and more than a third experienced “systemic” symptoms, such as joint pain, fatigue, or weakness, after being in the sun. To ward off these issues, WebMD suggests staying out of direct sunlight when the sun is strongest (between 10 a.m. and 4 p.m.), wearing protective clothing and hats, and being vigilant about applying and reapplying sunscreen. For anyone in the market for SPF protection, this is the only sunscreen the FDA wants you to use.

Fluorescent lights

You’ll need to be careful indoors, too—and not just because windows don’t fully block UV rays. Believe it or not, fluorescent and halogen bulbs can also emit ultraviolet rays and cause systemic flares. The Lupus Foundation of America recommends opting for bulbs with the lowest UV intensity, as well as investing in bulb filters or shields (like a standard acrylic plastic diffuser) with a nanometer reading of 380 to 400. LED lights may also be a good option: Although more research needs to be done on these lights, some people report that they have fewer flares around them.

Low vitamin D levels

How’s this for a frustrating paradox: While people with lupus need to stay out of the sun, a lack of vitamin D—which people usually get from sunlight exposure—may cause lupus symptoms to worsen, according to an Australian study. And that’s not all: Some corticosteroids used to treat lupus may lower vitamin D levels. Also troubling are findings from Johns Hopkins researchers that low vitamin D levels can increase the risk of organ damage and kidney failure in lupus patients. While more research is necessary, vitamin D supplements may help to prevent or improve lupus symptoms, and this may be something to discuss with your doctor. Don’t miss these 9 signs that could mean you’re not getting enough vitamin D.


Stress is taxing not just on the brain but also on the body. Studies indicate that up to 80 percent of patients with lupus reported “uncommon emotional stress” before the disease started. In fact, a recent study published in Arthritis & Rheumatology found that women who experienced trauma and PTSD had a three times greater risk of developing lupus than those who had not. While no one’s sure why—or if—there’s a connection, some scientists theorize that what causes lupus may be linked to the interplay of stress, which alters the production of naturally occurring steroid hormones and the body’s inability to suppress immune system agents like interferons. Find out the little things you should be doing to boost your immune system.
woman stress headacheg-stockstudio/Shutterstock


Exhaustion is not only a symptom of lupus—it can also trigger secondary flares. “Exhaustion can cause aberrant immune responses and sometimes can precipitate flares of autoimmune disease, including systemic lupus,” says Dr. Koumpouras. For this reason, he stresses, “it is very important for patients with systemic lupus to get enough sleep to help control the symptoms of fatigue and to avoid flares.”


A virus or bacteria that might make an ordinary person sick can make someone with lupus really sick. “Infections trigger the immune response, and a lupus response has difficulty turning off,” explains Dr. Koumpouras. “Therefore, significant infections can trigger aberrant immune responses. There are some thoughts and even some data to suggest that viruses, including Epstein-Barr virus, can trigger diseases.” The Korean Journal of Internal Medicine cites parvovirus B19 and retrovirus, in addition to Epstein-Barr, as potential contributing factors to lupus development. One note: It’s essential to figure out if your symptom—say, a fever—is caused by an infection or a flare since effective treatment will differ for each.


If you’re not careful, your medication may come with some very unintended side effects—namely, lupus flares. Medical News Today advises lupus patients to avoid sulfa-based antibiotics, such as Bactrim and Septra, as well as sleeping aids like melatonin and Rozerem. Dr. Koumpouras also cautions against taking antibiotics used to control acne, such as minocycline, if you have lupus. In addition to triggering lupus in some patients, certain medications can cause drug-induced lupus if the meds are taken for a long period of time. This is a temporary condition that causes lupus-like symptoms, but the condition generally clears up once the medication is stopped.


Even the air we breathe may cause lupus, according to new research. Scientists at the University of Cincinnati Academic Health Center found that particulate air pollution—like that from the exhausts of diesel-run vehicles—may trigger flares and worsen symptoms. Pollution may also be particularly hard on younger patients. One study found that air pollution is “strongly linked to disease activity in children and adolescents with [lupus].” Another study indicates that air pollution increases airway, lung, and systemic inflammation in children with lupus. If pollution is a particular concern, you won’t want to miss this breakdown of the most (and the least) polluted cities in the world.

Garlic, alfalfa sprouts, and other surprising foods

You are what you eat—and your lupus flares may reflect that. Both garlic (which contains immune-provoking substances like allicin, ajoene, and thiosulfinates) and alfalfa sprouts (thanks to the amino acid L-canavanine) can trigger flares, according to the Johns Hopkins Lupus Center. While a direct link between lupus and most other foods isn’t clear, there are still some specific items you’ll want to avoid. For example, foods laden with saturated fats—such as fried fare, overly processed foods, red meat, and high-fat dairy products—can increase cholesterol and may lead to inflammation. You might also want to steer clear of nightshade vegetables, such as white potatoes, tomatoes, and eggplant, since some people with lupus have reported a particular sensitivity to them. Now that you know the answer to the question “what is lupus,” find out how to tell if you have it with the 15 silent lupus symptoms you should never ignore.

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Dawn Yanek
Dawn Yanek is a senior editor at RD.com who covers current events, lifestyle, shopping, and entertainment. A former on-air spokesperson and parenting blogger who has appeared on more than 2,500 TV segments, Dawn has likely popped up on your television at some point as an expert or actress. She lives in New York with her husband and their two mind-bogglingly energetic kids.