What is the immune system?

The immune system incorporates different parts of the body – including certain blood cells, skin, bone marrow and more – that work to keep you healthy. The immune system protects you from infection by detecting and fighting diseases.

If infectious agents such as bacteria or viruses get into your body, immune cells usually kill or overwhelm them, removing the infection. This is known as the immune response.

Causes of autoimmune disease

Autoimmune disease occurs when, instead of attacking bacteria, viruses or other sources of infection, the immune system attacks healthy organs and tissues.

It's not known why this happens, although autoimmune conditions most often affect people with a genetic predisposition. An environmental factor such as an infection, stress, medication, diet or even ultraviolet radiation then triggers the symptoms of the autoimmune disease.  

Microorganisms that live in the gut might also influence autoimmune responses.

While this explains why autoimmune disease occurs generally, it’s not usually possible for doctors to determine why it occurs in an individual.

Types and symptoms of autoimmune disease

There are more than 80 different autoimmune diseases. Most of them are long-term illnesses, with the severity of symptoms changing over time.

Some of the more common autoimmune diseases include:

• Coeliac disease – the immune system reacts to gluten (found in wheat and other grains) and damages the small intestine. Coeliac disease causes flatulence, diarrhoea and abdominal pain.
• Lupus – many parts of the body can be affected, including the skin, muscles, joints, lungs, heart and kidneys.
• Rheumatoid arthritis – bone and cartilage are damaged, causing tender, swollen and stiff joints.
• Graves’ disease – the thyroid gland is overactive, causing anxiety, heart palpitations, weight loss and irritated or bulging eyes.
• Multiple sclerosis – the nervous system is affected, causing muscle weakness and poor coordination, sight problems and, in some cases, cognitive difficulties.
• Type 1 diabetes – the pancreas does not produce enough insulin to manage blood sugar levels, resulting in thirst, hunger and frequent urination.

Most people have signs and symptoms of autoimmune disorders for a long time before they seek help. It can also take a long time to diagnose an autoimmune disease because some symptoms, such as tiredness and ‘just not feeling right’, are commonly felt by many adults, while symptoms can come and go. With most conditions, there is no one test that confirms a diagnosis.

If you think you might have an autoimmune disease, use the healthdirect Symptom Checker and see your doctor. They will investigate your symptoms more closely, examine you and ask you about your general health. They might arrange a blood test, x-ray, MRI or biopsy.

Depending on your condition, your doctor might also refer you to a specialist for further investigation or advice on treatment options.

Treatment of autoimmune disease

While there is no cure for autoimmune diseases, help is available. People diagnosed with autoimmune diseases often benefit from:

• a healthy diet
• maintaining a healthy weight
• plenty of sleep
• achieving the right combination of rest and exercise
• reducing stress where possible, and finding ways to deal with unavoidable stress

Specific medicines and lifestyle changes can help. For example, people with type 1 diabetes inject insulin, while those with autoimmune diseases that affect skin receive advice about the sun, bathing, creams and lotions. People with Coeliac disease must follow a gluten-free diet.

In some people, autoimmune diseases can be mild, while others will need to invest a lot of time and care in managing their condition. However, most people with autoimmune conditions are able to live a full and enjoyable life.

Where to seek more help

You can find organisations that support people with specific autoimmune diseases at these sites:

• Autoimmune Resource & Research Centre
• Australasian Society of Clinical Immunology and Allergy