Systemic Lupus Erythematosus

Systemic Lupus Erythematosus, commonly known as lupus or SLE, is an autoimmune disease in which the body's immune system — normally responsible for defending against infection — mistakenly identifies healthy tissue as a threat and attacks it. This results in inflammation that can affect several different body systems at once, including the joints, skin, kidneys, blood cells, lungs, heart, nervous system and blood vessels.

Lupus is often described as a condition of many faces, because it can present very differently from one person to the next, and even differently in the same person over time.

Understanding Autoimmune Disease: How Lupus Develops

The immune system normally produces antibodies that identify and target foreign invaders such as bacteria and viruses, while leaving the body's own healthy cells alone. In lupus, this system malfunctions: it produces autoantibodies that mistakenly target the body's own tissue, triggering widespread inflammation.

Because these autoantibodies can circulate throughout the bloodstream, they are capable of affecting almost any organ or tissue, which explains why lupus can cause such a wide and varied range of symptoms. The exact trigger for this immune malfunction is not fully understood, but it is thought to involve a combination of genetic susceptibility and environmental triggers that, together, cause the immune system to lose its normal ability to distinguish "self" from "foreign."

Lupus occurs more frequently in women than men, by nearly 10 to 1, and may occur at any age, though it is most often diagnosed in the reproductive years. There is currently no cure for lupus, but with an appropriate combination of treatments, many people are able to manage their symptoms effectively and enter remission — a period with few or no symptoms — although there is always a chance the condition will become active again.

Types of Lupus

While systemic lupus erythematosus is the most well-known and often most serious form, "lupus" actually refers to a group of related conditions.

• Systemic Lupus Erythematosus (SLE): The most common and often most serious form of lupus, capable of affecting multiple organ systems throughout the body, including the joints, skin, kidneys, blood cells, lungs, heart and nervous system.
• Cutaneous (Discoid) Lupus: A form of lupus limited to the skin, causing a rash or sores, typically on the face, neck and scalp, that can lead to scarring. Some people with cutaneous lupus later go on to develop SLE, though most do not.
• Drug-Induced Lupus: A lupus-like reaction triggered by certain long-term medications. Symptoms generally resemble SLE but tend to resolve within months after the triggering medication is stopped.
• Neonatal Lupus: A rare condition affecting some babies born to mothers with certain lupus-related antibodies. Most symptoms, such as a skin rash, resolve on their own within the first several months of life, though a small proportion of affected babies have a heart problem that requires treatment.

How SLE Affects Different Body Systems

Because lupus can involve almost any organ system, its presentation varies enormously between individuals. Understanding the range of ways it can manifest helps illustrate why lupus is sometimes challenging to recognise and diagnose.

• Joints and Muscles: SLE may cause pain, stiffness and swelling, commonly affecting the fingers, hands, wrists and knees, sometimes resembling rheumatoid arthritis though usually without permanent joint damage.
• Skin: A butterfly-shaped (malar) rash across the cheeks and bridge of the nose may develop. Patients may experience other rashes, mouth or nose sores, and increased sensitivity to sunlight, which can trigger flares.
• Kidneys: SLE causes inflammation of the kidneys, known as lupus nephritis. It is one of the more serious complications of SLE and can affect the kidneys' ability to filter waste from the blood if not detected and treated.
• Blood and Blood Vessels: SLE causes reduced red blood cells (anaemia), low white blood cell or platelet counts, and inflammation of blood vessels (vasculitis), which can affect circulation to various parts of the body.
• Heart and Lungs: Inflammation of the lining around the heart (pericarditis) or lungs (pleuritis), causing chest pain, particularly when breathing deeply, and in the long term, an increased risk of cardiovascular disease.
• Nervous System: Headaches, mood changes, cognitive difficulties (sometimes called "lupus fog"), and, less commonly, seizures or more significant neurological symptoms are sometimes experienced by those with SLE.
• Digestive System: Patients may experience general discomfort, nausea, or, less commonly, inflammation affecting the digestive tract.

Symptoms of SLE

Symptoms of SLE vary from person to person and may go into remission for periods of time before flaring up again. Joint pain and swelling are common symptoms of SLE, as it often affects the fingers, hands, wrists and knees. Other common symptoms include:

• Chest pain when breathing
• Fatigue
• Fever
• General discomfort
• Hair loss
• Weight loss
• Mouth sores
• Skin rash (a butterfly-shaped rash develops in some people with SLE and typically appears over the cheeks and bridge of the nose)

Understanding Flares and Remission

One of the more distinctive features of lupus is its unpredictable, fluctuating course. Rather than following a steady pattern, symptoms often come and go in what are known as flares and periods of remission.

• Flares: A flare refers to a period when disease activity increases and symptoms worsen or new symptoms appear, sometimes triggered by identifiable factors such as sun exposure, infection, stress or certain medications, and sometimes occurring without any clear cause.
• Remission: Remission refers to a period when symptoms are minimal or absent and disease activity is low. With appropriate treatment, many people with lupus are able to achieve extended periods of remission, though the disease can become active again even after long quiet periods.

Because of this fluctuating pattern, ongoing monitoring — even during periods of remission — helps detect early signs of a flare and adjust treatment before symptoms become more severe.

What Causes SLE?

Experts do not know for certain what causes SLE, though certain factors about a person's health or environment may trigger it, including:

• Genetics: No single gene or group of genes has been proven to cause lupus, although certain gene variations have been linked to lupus.
• Hormones: Certain hormones, such as oestrogen, may increase the chances of developing lupus, which may help explain why the condition is so much more common in women.
• Environmental factors: These include aspects of where a person lives, works or spends time. For example, the amount of sunlight or polluted air a person is exposed to could affect their risk of lupus.
• Health history: Prior health conditions, prolonged stress or smoking could trigger lupus in someone who is otherwise genetically predisposed.

Risk Factors for SLE

Anyone can develop lupus, though risk is higher if one or both parents have it. The following factors may increase the risk of developing the condition:

• Gender: Women are nine to ten times more likely to develop SLE than men.
• Age: SLE can occur at any age, but most people are diagnosed with it in their 20s and 30s.
• Family history: A person is more likely to develop SLE if they have a close family member with it.
• Ethnicity: Lupus is more commonly diagnosed in certain ethnic groups, including those of Asian, African and Hispanic descent, and may also tend to be more severe in these groups.

Possible Complications of SLE

When lupus is active over a long period, or not adequately managed, it can lead to complications affecting specific organs or overall health.

• Lupus nephritis: Ongoing kidney inflammation can, over time, affect kidney function and, in more severe or poorly controlled cases, contribute to chronic kidney disease
• Cardiovascular disease: Chronic inflammation, together with some medications used to treat lupus, is associated with an increased long-term risk of heart disease and stroke
• Increased infection risk: Both the disease itself and some of the immune-suppressing medications used to treat it can make a person more susceptible to infections
• Avascular necrosis: Reduced blood flow to bone tissue, sometimes related to long-term steroid use, can occasionally lead to bone damage, most often in the hip
• Cognitive and neurological effects: Lupus that affects the nervous system can, in some cases, contribute to memory or concentration difficulties, mood changes, or, less commonly, more significant neurological symptoms

Lupus and Pregnancy

Because SLE most commonly affects women during their reproductive years, pregnancy is an important and common consideration for many patients living with the condition.

• Planning for pregnancy: Ideally, lupus should be in a stable, well-controlled state for around six months before conception, as pregnancies begun during a flare carry a higher risk of complications for both mother and baby
• Pregnancy risks: Women with lupus have a higher risk of certain pregnancy complications, including high blood pressure during pregnancy and pre-term birth, and benefit from closer monitoring throughout pregnancy
• Neonatal lupus: Certain lupus-related antibodies can, in rare cases, be passed to the baby and cause neonatal lupus, most commonly a temporary skin rash, though a small number of affected babies have a heart problem that requires treatment
• Coordinated care: Close collaboration between a rheumatologist and obstetrician, ideally starting before conception, allows medications to be reviewed and adjusted to protect both maternal and fetal health throughout pregnancy

How Is SLE Diagnosed?

Lupus can be tricky to diagnose, as it causes many different symptoms that can overlap with other conditions. Patients should not be afraid to tell their healthcare provider about anything they have felt or noticed, however minor it may seem, as small details can be important pieces of the diagnostic picture.

• Antinuclear Antibody (ANA) Test: A blood test that checks for antibodies that mistakenly target the body's own cells. A positive ANA test is common in SLE, though it can also occur in other conditions or in people without any disease, so it is interpreted alongside symptoms and other tests.
• Specific Antibody Tests: Blood tests for more specific antibodies, such as anti-dsDNA and anti-Sm antibodies, which are more closely associated with SLE and can help support the diagnosis and, in some cases, track disease activity.
• Complement Levels: Blood proteins involved in immune function, called complement, are often reduced during active lupus, so measuring their levels can help assess disease activity.
• Complete Blood Count: Checks for anaemia, and low white blood cell or platelet counts, which are common findings in SLE and can also indicate how active the disease is.
• Urinalysis: Checks for protein, blood or other abnormalities in the urine that may indicate kidney involvement (lupus nephritis).
• Biopsy: A small tissue sample from the skin or kidney can show whether the immune system has caused inflammation or damage in that organ, which helps confirm diagnosis and guide treatment, particularly for suspected kidney involvement.

Because no single test can confirm lupus on its own, diagnosis is generally made by combining the pattern of symptoms with the results of several of these tests, often guided by established diagnostic criteria used by rheumatologists.

Preventing SLE Flare-Ups

Flare-ups may be prevented or reduced by avoiding activities that trigger symptoms, such as:

• Avoiding sun exposure: Spending too much time in the sun can trigger SLE symptoms in some people. Try to avoid going outside when the sun is brightest, wear sun-protective clothing, and use sunscreen with at least SPF 50.
• Staying active: It may sound counterintuitive, with joint pain making it difficult to move. However, gently moving and using the joints can be one of the best ways to relieve symptoms like pain and stiffness.
• Getting enough sleep: It can be frustrating living with SLE. Managing stress and ensuring sufficient sleep can help prevent flare-ups for some people.
• Regular follow-up: Working closely with a healthcare provider to monitor disease activity, even during quiet periods, allows early signs of a flare to be caught and addressed before symptoms become more severe.
• Preventing infections: Because infections can sometimes trigger flares, staying up to date on recommended vaccinations and practising good hygiene can help reduce this risk.

Lupus Myths and Facts

Myth: Lupus is contagious
Fact: Lupus is an autoimmune condition, not an infection, and cannot be spread from person to person

Myth: Lupus only affects the skin.
Fact: While skin symptoms, including the well-known butterfly rash, are common, systemic lupus erythematosus can affect many organs, including the joints, kidneys, heart, lungs, blood and nervous system.

Myth: A lupus diagnosis means a lifetime of severe symptoms.
Fact: Many people with lupus achieve extended periods of remission with appropriate treatment, and the severity of the condition varies considerably between individuals.

Myth: Only women get lupus.
Fact: While lupus is far more common in women, men can develop the condition too, and it can sometimes be more severe in men when it does occur.

Myth: People with lupus should avoid all physical activity.
Fact: Gentle, regular movement is generally encouraged, as it can help relieve joint pain and stiffness, improve fatigue, and support overall physical and mental wellbeing.

Living with Lupus

A lupus diagnosis often brings uncertainty, given how unpredictable the condition can be from one person to the next, and even from one month to the next in the same person. With the right combination of medical treatment, lifestyle adjustments and regular monitoring, however, many people with lupus lead full, active lives, with long stretches of stable disease or remission.

Ongoing communication with a rheumatology-led care team, awareness of personal flare triggers, and attention to overall physical and emotional wellbeing all play an important role in successfully managing lupus over the long term.