Systemic lupus: symptoms, diagnosis and treatment

Lupus UK explains that in lupus the immune system, instead of only attacking germs, mistakenly attacks the body. It makes autoantibodies, and clumps called immune complexes can build up in organs such as the skin, joints and kidneys, causing swelling, pain and damage.

The NHS says it is an autoimmune condition and is not contagious. Systemic lupus erythematosus is what most people mean by lupus; it can affect any part of the body. Other forms include cutaneous lupus, which mainly affects the skin, neonatal lupus and drug-induced lupus, which Lupus UK says is a temporary reaction to medicines and not true lupus.

The NHS lists joint and muscle pain, extreme tiredness that does not go away with rest, and rashes that usually come after sun exposure and often cover the nose and cheeks. Other symptoms can include headaches, mouth ulcers, a high temperature, hair loss, weight loss, swollen glands, depression and anxiety, chest or tummy pain, and colour changes in the fingers and toes in the cold (Raynaud's).

Lupus UK says almost 9 out of 10 people with lupus report fatigue, and that two people rarely share the exact same experience. The NHS describes severity as mild (joint, skin problems and tiredness), moderate (inflammation of other parts of the body, including lungs, heart and kidneys) or severe (damage to heart, lungs, brain or kidneys that can be life-threatening).

The causes are not fully understood. The NHS lists possible triggers such as viral infection, certain medicines, sunlight, puberty, childbirth and menopause. Lupus UK says research suggests that genes, hormones and infections may all play a role, and that there is no genetic test for lupus.

More women than men get lupus, according to the NHS, and it is more common in women with an African, Caribbean, Asian or Chinese background. Lupus UK says it often begins between ages 15 and 55 and that around 2 in 10 cases start in childhood.

The NHS says lupus is not always easy to diagnose because symptoms resemble those of other conditions. A GP will usually do blood tests, and may diagnose lupus if there are high levels of a certain antibody alongside typical symptoms. Scans of the heart, kidneys or other organs may be arranged.

Lupus UK explains that the usual route is GP, then referral to a rheumatologist, who applies diagnostic criteria. Blood tests include ANA, which it says is present in most people with lupus but also in about 1 in 10 people with no health conditions, and anti-dsDNA, which is highly specific to lupus. Urine is checked for blood and protein, because about a third of people with lupus have kidney involvement.

Because a positive ANA alone does not mean lupus, results are always read alongside symptoms. People with mainly skin problems may be assessed by a dermatologist.

The NHS lists anti-inflammatory medicines such as ibuprofen, hydroxychloroquine for fatigue, skin and joint problems, and steroid tablets, injections and creams for kidney inflammation and rashes. Immunosuppressant or biological medicines are sometimes used for severe lupus.

Lupus UK says hydroxychloroquine is a disease-modifying treatment that usually begins helping after about a month and may take up to a year to reach full effect. Regular eye checks are arranged because of a rare risk to vision. Steroids work fast and are often used as a bridge, but are reduced slowly because of side effects. Immunosuppressants such as methotrexate and azathioprine and biologics such as belimumab and rituximab are used for moderate to severe disease.

Arthritis UK adds that before starting hydroxychloroquine a doctor may check liver and kidney function, and that benefits may take 12 weeks or longer, so it should be continued even when symptoms improve unless side effects are severe.

The NHS advises high-factor sunscreen (at least factor 50) and a hat, pacing, staying active even on a bad day, relaxation techniques, telling your employer, asking for help, a balanced diet with vitamin D and calcium, and stopping smoking, which makes lupus worse. It also advises avoiding direct sunlight and long periods in rooms with fluorescent lights.

Regular monitoring matters. The NHS says that once lupus is confirmed you will be advised to have regular checks, such as blood tests for anaemia and urine tests for kidney problems. Lupus UK notes that overlap with Sjogren's syndrome, Raynaud's phenomenon and antiphospholipid syndrome is common.

The NHS says lupus can cause complications in pregnancy and advises seeing a doctor before trying to conceive so that risks can be discussed and medicines reviewed. Lupus UK notes an increased risk of miscarriage, but says that with close monitoring many people with lupus now have successful pregnancies.

Do not stop lupus medicines on your own when planning pregnancy. Ask your rheumatology team which medicines are suitable.

Lupus is managed mainly by NHS rheumatology teams, sometimes with specialist lupus nurses and kidney, skin or heart specialists. GPs share prescribing and monitoring.

A private rheumatologist can offer an earlier diagnostic assessment, but long-term monitoring and shared-care medicines usually continue alongside the GP and NHS team. Antibody results should be interpreted in context rather than in isolation.