Lupus is an autoimmune condition that affects the body's defences against illnesses and infections. Around 50,000 people are thought to have lupus, according to Lupus UK. Around 90% of people with lupus are women, usually aged between 15 and 50. People of African-Caribbean, Chinese and Asian descent are more likely to develop lupus than white (Caucasian) people.
Lupus can cause symptoms including fatigue, skin rashes, joint pain and swelling. Lupus symptoms are shared with other conditions, which can make it hard to diagnose.
The symptoms of lupus can be mild but may be life-threatening.
The causes of lupus are still poorly understood, but it is thought to be due to genetic and environmental factors.
Types of lupus
The three main types of lupus are:
- Systemic lupus erythematosus (SLE) - This condition is what most people mean when they refer to lupus. Systemic lupus erythematosus can affect body tissue anywhere in the body and any organ. It can affect a person’s quality of life through pain, fatigue and associated depression and anxiety.
- Discoid lupus erythematosus (DLE) - Discoid lupus erythematosus is usually a milder type of lupus and usually only affects the skin. Symptoms include red, circular, scaly marks on the skin, hair loss and bald patches. A person with DLE may have to avoid direct sunlight.
- Drug-induced lupus - More than 100 medications are known to cause lupus symptoms in some people. These usually stop if the medication is stopped or changed after seeking medical advice.
Symptoms of lupus
The symptoms of lupus differ from one person to another and depend on the type of lupus. Some people have just a few symptoms, while others have many. In addition there are many different symptoms of lupus because the disease can affect any part of the body.
Common symptoms of lupus include:
- Joint pain (arthralgia)
- Unexplained fever (more than 38C or 100.4F)
- Swollen joints ( arthritis)
- Prolonged or extreme fatigue
- Skin rash
- Ankle swelling and fluid accumulation
- Swollen lymph glands
- A butterfly-shaped rash across the cheeks and nose
- Hair loss
- Depression and anxiety
- Mouth and nose ulcers
- Pale or painful fingers or toes from cold or stress ( Raynaud's phenomenon)
- Memory loss
- Migraine headaches
- Shortness of breath
The SLE type of lupus can lead to complications, including kidney failure (lupus nephritis), heart and cardiovascular disease such as stroke.
People with SLE are also more likely to have another autoimmune condition including:
SLE can be a concern in pregnancy as it may increase the risk of pre-eclampsia, miscarriage, stillbirth and premature birth.
How is lupus diagnosed?
The diagnosis is made when a person has several symptoms of the disease. Blood tests may be carried out to help confirm a lupus diagnosis. These blood tests used to diagnose lupus include:
- Antinuclear antibody (ANA) test - An antinuclear antibody test is a sensitive screening tool used to detect autoimmune diseases, including lupus. Antinuclear antibodies (ANAs) are antibodies that are directed against certain structures within a cell's nucleus (thus, antinuclear antibody). ANAs are found in particular patterns in people with autoimmune diseases - those in which a person's immune system works against his or her own body. Around 95% of people with SLE have this antibody. However, the test may also be positive in many people who are healthy or have another autoimmune disease.
- Anti-DNA antibody test - Having the anti-DNA antibody means a person is very likely to have SLE, but people without the condition can still test positive for it. Anti-DNA antibody levels are often higher during a disease flare-up.
- Complement level test - Complement is a test for a chemical associated with immune system activity, which may be a sign of SLE activity.