Lupus Erythematosus

What happens in lupus

In lupus, the immune system produces autoantibodies against components of the body's own cells, especially material from the cell nucleus. These antibodies form immune complexes that deposit in tissues and trigger inflammation. Which organs are affected varies from person to person, so no two people have exactly the same disease.

Types of lupus

Symptoms

Lupus symptoms often come and go in flares and remissions.

Common symptoms

• severe tiredness
• joint pain and swelling, often in the hands, wrists and knees
• butterfly (malar) rash across the cheeks and bridge of the nose, sparing the creases beside the nose
• rashes that appear or worsen after sun exposure
• mouth or nose ulcers, often painless
• hair loss or thinning
• fever without infection
• swollen lymph nodes
• Raynaud's phenomenon: fingers turning white then blue in the cold

Organ involvement in SLE

• Kidneys (lupus nephritis): often silent at first, found by urine tests. Can cause swelling and high blood pressure
• Heart and lungs: pericarditis and pleurisy, with sharp chest pain worse on breathing
• Blood: anemia, low white cells, low platelets
• Brain and nerves: headaches, seizures, cognitive difficulty, mood changes, stroke
• Blood clots: especially with antiphospholipid syndrome
• Eyes and mouth: dryness, sometimes with Sjögren's syndrome

Causes and risk factors

The exact cause is unknown. Lupus arises from a combination of:

• genes: a family history of lupus or other autoimmune disease
• sex hormones: much more common in women, especially of childbearing age
• ethnicity: more common and often more severe in Black, Hispanic, Asian and Native American people
• environmental triggers: ultraviolet light, infections such as Epstein-Barr virus, smoking, some medicines, and silica dust

Diagnosis

There is no single test. Rheumatologists combine symptoms, examination and tests:

• Antinuclear antibody (ANA): positive in almost everyone with SLE, but also in many healthy people, so a positive result alone does not mean lupus
• Specific antibodies: anti-double-stranded DNA (anti-dsDNA) and anti-Smith are highly specific for SLE. Anti-Ro, anti-La, and antiphospholipid antibodies are also checked
• Complement levels (C3 and C4), which fall during active disease
• Blood count, kidney and liver function, ESR and CRP
• Urine tests for protein and blood, repeated regularly
• Kidney biopsy if nephritis is suspected
• Skin biopsy for cutaneous lupus

The 2019 EULAR/ACR classification criteria require a positive ANA and then score clinical and immunological features. These are used mainly for research, but they guide diagnosis.

Treatment

Treatment aims to control symptoms, prevent flares and protect organs, while limiting steroid side effects.

• Hydroxychloroquine: recommended for almost everyone with SLE. It reduces flares, protects organs, lowers clot risk and improves survival. Yearly eye checks are needed after the first 5 years, or sooner with risk factors.
• Sun protection: broad-spectrum sunscreen, protective clothing and avoiding peak sun.
• NSAIDs for joint pain, used cautiously because of kidney effects.
• Glucocorticoids (such as prednisone) for flares, tapered to the lowest dose or stopped when possible.
• Immunosuppressants: methotrexate, azathioprine, mycophenolate, cyclophosphamide or calcineurin inhibitors, depending on organs involved.
• Biologic and targeted medicines: belimumab and anifrolumab for SLE, and newer options for lupus nephritis.
• Topical steroids and calcineurin inhibitors for skin lupus.
• Anticoagulants for antiphospholipid syndrome.
• Stopping the trigger drug in drug-induced lupus.

Living with lupus

• pace activities and prioritize sleep
• exercise regularly to reduce fatigue and protect bones and heart
• stop smoking, which worsens skin lupus and reduces the effect of hydroxychloroquine
• keep vaccinations up to date (check which live vaccines to avoid on immunosuppressants)
• manage heart risk factors, because lupus raises cardiovascular risk
• plan pregnancies when lupus is quiet, with a rheumatologist and high-risk obstetrician

Outlook

Most people with lupus now live a normal or near-normal lifespan. Outcomes have improved greatly with earlier diagnosis and better treatments. Kidney involvement, heart disease and infections remain the main serious risks, which is why regular monitoring is important. Cutaneous lupus alone rarely becomes systemic.

Frequently asked questions

What is lupus erythematosus?

It is an autoimmune disease where the immune system attacks healthy tissue. It can affect only the skin (cutaneous lupus) or many organs, including the joints, kidneys, blood, heart and brain (systemic lupus erythematosus).

What are the first signs of lupus?

Common early signs are fatigue, joint pain or swelling, a rash on the cheeks or sun-exposed skin, fever, mouth ulcers and hair loss. Symptoms often come and go, which can delay diagnosis.

How is lupus diagnosed?

Doctors combine symptoms and examination with blood and urine tests, including ANA, anti-dsDNA and anti-Smith antibodies, complement levels, blood counts and urine protein. Sometimes a skin or kidney biopsy is needed.

Is lupus curable?

There is no cure, but lupus can be controlled. Hydroxychloroquine, sun protection and, when needed, immunosuppressive or biologic medicines keep most people well, reduce flares and prevent organ damage.

What is the difference between lupus and discoid lupus?

Discoid lupus is a type of cutaneous lupus that affects only the skin, causing scaly, scarring patches, often on the face and scalp. Systemic lupus affects internal organs. Some people with SLE also have discoid lesions.