Autoimmune disorders are conditions in which the immune system mistakenly attacks the body's own cells, tissues or organs. They are also commonly called autoimmune diseases or autoimmune conditions.
The immune system normally protects the body from infection and other threats. In autoimmune disease, parts of that defence system target healthy tissue, causing inflammation, pain, organ damage or changes in how the body functions.
How Autoimmunity Works
The immune system uses many checks to tell the difference between the body and outside threats. Autoimmunity can develop when those checks fail or when immune responses continue after they should have stopped.
Some autoimmune diseases mainly affect one organ. Type 1 diabetes affects insulin-producing cells in the pancreas, while coeliac disease affects the small intestine after exposure to gluten. Other conditions, such as lupus, can affect several systems at once.
Examples
Autoimmune conditions include:
- rheumatoid arthritis, which mainly affects joints;
- systemic lupus erythematosus, which can affect skin, joints, kidneys, blood, brain and other organs;
- type 1 diabetes, which affects insulin production;
- coeliac disease, triggered by gluten in genetically susceptible people;
- multiple sclerosis, which affects the central nervous system;
- autoimmune thyroid disease, including Graves' disease and Hashimoto's thyroiditis;
- psoriasis and psoriatic arthritis;
- inflammatory bowel disease, including Crohn's disease and ulcerative colitis.
The conditions differ greatly. A mild skin-limited disorder and a severe multi-organ condition should not be treated as the same problem simply because both involve autoimmunity.
Symptoms
Symptoms depend on the condition and the organs involved. Common patterns can include fatigue, joint pain, swelling, rashes, bowel symptoms, fever, mouth ulcers, weight change, weakness, numbness, dry eyes, hair loss or symptoms that come and go in flares.
Because many symptoms are shared with non-autoimmune conditions, diagnosis usually depends on the full pattern rather than one symptom.
Causes and Risk Factors
Most autoimmune disorders have more than one cause. Genetic susceptibility can increase risk, but genes alone rarely explain the whole condition. Environmental triggers, infections, smoking, hormones, gut factors, medicines and chance immune events may all play a part depending on the disease.
NIAID notes that many autoimmune diseases disproportionately affect women, including rheumatoid arthritis, multiple sclerosis and systemic lupus erythematosus. Family history can also matter, although relatives may develop different autoimmune conditions rather than the same one.
Diagnosis
Diagnosis depends on the suspected condition. It may include:
- symptom history and examination;
- blood tests for inflammation, blood counts, organ function and autoantibodies;
- urine tests where kidney involvement is possible;
- imaging such as X-ray, ultrasound or MRI;
- biopsy in selected conditions;
- referral to a specialist such as a rheumatologist, endocrinologist, gastroenterologist, neurologist or dermatologist.
Autoantibody tests can be useful, but a positive result does not always prove disease. Results need to be interpreted with symptoms and examination findings.
Treatment
Treatment depends on the disease, severity and organs involved. It may include pain control, anti-inflammatory medicine, corticosteroids, disease-modifying drugs, biologic medicines, hormone replacement, diet changes, physical therapy or organ-specific treatment.
Some treatments calm the immune system generally. Others target specific immune pathways. The aim is usually to reduce inflammation, prevent damage, control symptoms and keep the person functioning as well as possible.
Flares and Long-Term Care
Many autoimmune diseases fluctuate. A flare is a period when symptoms or inflammation worsen. Triggers can include infection, stress, missed medicine, hormonal changes or unknown factors.
Long-term care often involves monitoring blood tests, symptoms, medicine side effects and organ function. Some people have long stable periods. Others need repeated treatment changes.
Research
Autoimmune disease research studies immune cells, genetics, infection links, tissue damage, sex differences, microbiome effects and targeted therapies. Better understanding of immune pathways has already changed treatment for conditions such as rheumatoid arthritis, psoriasis and inflammatory bowel disease.
See Also
References
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