Systemic lupus erythematosus (SLE)

Systemic lupus erythematosus (SLE or lupus) is a chronic autoimmune disease in which the immune system attacks cells and tissue in the body, resulting in inflammation and tissue damage. SLE can affect any part of the body, but most often harms the heart, joints, skin, lungs, blood vessels, liver, kidneys and nervous system.

The course of SLE is highly variable and is characterized by periods of flares, interspersed with periods of improvement or remission. Some patients experience a relatively benign disease with little medical intervention, while others can have a serious and aggressive progression that can lead to significant and potentially lifethreatening damage to organs such as the kidneys, brain, heart and lungs. The cause of SLE is unknown, but is thought to be multifactorial, with genetic, hormonal and environmental factors all playing a role.

There are three major types of lupus:

• Discoid (cutaneous) – is always limited to the skin (rash) and is identified by a rash that may appear on the face, neck and scalp
• Systemic – can affect the skin, joints and almost any organ or system of the body
• Drug-induced – occurs after the use of certain prescribed medicines.

Who is affected?

The number of SLE cases varies around the world. The incidence of new cases has been reported to range between 1 and 10 per 100,000 person-years, while overall prevalence varies between 20 and 70 per 100,000.

SLE is more common in women than in men. In particular, women of childbearing age (15–40 years), are 9 times more likely than men of the same age to develop the disease.

SLE is also more prevalent in certain ethnic groups. African-American and Hispanic people are three times more susceptible to the disease than Caucasians: in one American study, the prevalence was 1:245 among Afro- Caribbean women aged 15–64 years, compared with 1:700 among Caucasian women in the same age range. Asians are also at higher risk of developing the disease; in China, it is estimated that more people have SLE than have rheumatoid arthritis.

There is evidence that genetics have a role in lupus. The frequency of lupus in identical twins, and the increased prevalence of lupus among first- and second-degree relatives of lupus patients have been used to research this genetic component, and recent studies have started to identify the immune system pathways that may be involved.

What are the symptoms?

The course of lupus varies by individual and symptoms come (flares) and go (remission). There is no way to predict when a flare will happen, how bad it will be, or how long it will last. When you have a lupus flare, you may have new symptoms in addition to those you have had in the past. Children can get lupus, but it more commonly develops in the teen years or later. Lupus in children appears to be more severe than in adults when vital organs, such as the kidneys and heart, are involved. This may be due to age-related differences in the disease, a child’s stage of development, or differences in access to treatment.

The most common symptoms of lupus, which are the same for females and males, are:

• extreme fatigue (tiredness)
• headaches
• painful or swollen joints
• fever
• anemia (low numbers of red blood cells or hemoglobin, or low total blood volume)
• swelling (edema) in feet, legs, hands and/or around eyes
• pain in chest on deep breathing (pleurisy)
• butterfly-shaped rash across cheeks and nose
• sensitivity to light or the sun (photosensitivity)
• hair loss (alopecia)
• abnormal blood clotting
• fingers turning white and/or blue when cold (Raynaud’s phenomenon)
• mouth or nose ulcers.

How is SLE diagnosed?

Diagnosis is difficult and timeconsuming, as there is no single test that can determine whether a person has or will develop lupus, and the diagnosis is based on a combination of physical symptoms and laboratory results.

The American College of Rheumatology (ACR) has developed a classification system to help identify patients with lupus. The criteria include: malar rash, discoid rash, photosensitivity, oral ulcers, arthritis, serositis (pleuritis or pericarditis), renal disorder, neurological disorder (seizures or psychosis), hematological disorder, immunologic disorder and antinuclear antibodies. A diagnosis of lupus is made when at least four of the above criteria are present, either serially or simultaneously, during any interval of observation.