What is systemic lupus erythematosus?
The exact causes of systemic lupus erythematosus (SLE) remain unclear. However, genetic, hormonal, and environmental factors may contribute to the development of the disease.
SLE is a unique type of lupus because it causes widespread inflammation that can involve multiple tissues and organ systems.
SLE is also the most common type of lupus, according to the Centers for Disease Control and Prevention (CDC). The National Institutes of Health (NIH) estimate that SLE affects between 322,000 and 1.5 million people in the United States. It is difficult to know exactly how many people have SLE because its symptoms are similar to those of other health conditions.
In this article, we discuss SLE symptoms, causes, and treatments. We also explain when people should see a doctor.
SLE can cause fatigue and fever.
SLE symptoms can come and go in flares. A lupus flare refers to a period during which the disease is actively producing symptoms. A person with lupus enters remission once their symptoms go away.
The severity of SLE flares can range from mild to severe. People may also experience symptoms that affect their kidneys, lungs, heart, or brain. SLE can affect nearly every organ in the body, so symptoms may vary widely from person to person.
People who have SLE may experience a range of symptoms, such as:
- skin problems, including rashes and tiny red spots
- painful or swollen joints
- weight loss
- sun sensitivity
- mouth ulcers
- anemia, or low red blood cell count
- leukopenia, or low white blood cell count
- chest pain
- vision problems
- abdominal pain
- nausea or vomiting
- difficulty breathing
- hair loss
- edema, or swelling of the limbs
Between one-third and one-half of people living with lupus experience inflammation that affects their kidneys, resulting in a condition called lupus nephritis. Without treatment, lupus nephritis can progress to end-stage renal disease, which is a life-threatening condition.
Lupus nephritis causes the following symptoms:
- painful or swollen joints
- muscle pain
- a butterfly-shaped rash on the face
SLE can affect the heart, leading to inflamed tissue around this organ and abnormal heart valves, among other issues. Atherosclerosis, a form of heart disease, is more common among people with SLE than among those who do not have this condition.
SLE can damage the nervous system and contribute to the following conditions:
Pictures of SLE symptoms
Image credit: James Heilman, MD, 2016.
Image credit: James Heilman, MD, 2016
Image credit: Stephane Vignes, Jerome Bellanger, 2008.
The exact cause of SLE remains unknown. However, variations or mutations in specific genes can increase a person's risk of developing SLE.
The genetic mutations that researchers have associated with SLE often involve genes that regulate the body's immune function, which are called major histocompatibility complex (MHC) genes.
Not everyone with an SLE gene variation will develop the condition, however.
Several other factors can increase the risk of someone developing SLE. Women are 10 times more likely to develop lupus than men, according to the American College of Rheumatology.
Other factors that can contribute to SLE include:
- sex hormones
- exposure to toxic chemicals, sunlight, or certain medications
- viral infections
Currently, there is no cure for SLE. Treatments focus on reducing symptoms — or inducing remission — and preventing severe complications, such as end-stage renal disease.
Depending on the symptoms and the affected organs, a person with SLE may receive one or more of the following types of medication:
- nonsteroidal anti-inflammatory drugs (NSAIDs), which include aspirin
- antimetabolites, such as methotrexate
- antimalarials, including chloroquine (Aralen)
- corticosteroids, for example, prednisone (Deltasone) creams
- biologics, such as belimumab (Benlysta)
- immunosuppressive medications, which include azathioprine (Imuran) and cyclosporine (Neoral)
- blood thinners, such as warfarin (Coumadin)
These medications work to reduce either inflammation, the activity of the immune system, or damage to the body resulting from SLE.
Doctors will sometimes prescribe a combination of different medications to treat SLE.
Eating plant sources of protein, such as beans, may help treat SLE.
People who have SLE and lupus nephritis may wish to consider making the following dietary changes to help manage their symptoms:
- limiting sodium intake
- limiting saturated and trans fats
- purchasing fresh food as often as possible
- avoiding packaged food and premade meals
- eating smaller portions of animal proteins
- eating more plant-based proteins, such as nuts and beans
- eating potassium-rich foods, including bananas, potatoes, and whole-wheat bread
- eating foods that are low in phosphorus, such as fresh fruits and vegetables
When to see a doctor
People may wish to consider visiting the doctor if they experience SLE symptoms.
Those who have already received an SLE diagnosis should contact a doctor if they notice any new or worsening symptoms.
Other types of lupus
Although many people use the terms SLE and lupus interchangeably, there are other different types of lupus with unique symptoms and causes.
Discoid lupus erythematosus (DLE), or cutaneous lupus, only affects the skin. It causes a thick, scaly rash on the face, neck, and scalp.
Drug-induced lupus refers to lupus that develops after taking certain medications. It usually goes away after a person stops taking the medication.
Although systemic lupus erythematosus is a long-term condition with no known cure, the outlook is generally positive as long as a person receives appropriate treatment and regular follow-ups with their healthcare team. Most people living with lupus can live a normal life.
The long-term effects of SLE depend on the severity and frequency of flares. People who experience more intense and frequent flares may have a higher risk of developing further complications.
Early diagnosis and appropriate treatment can help initiate remission, prevent disease progression, and avoid potentially life-threatening complications.
Many women who have SLE can get pregnant and deliver healthy babies as long as they receive proper treatment throughout their pregnancy.