Autoimmune diseases are a broad range of related diseases in which a person’s immune system produces an inappropriate response against its own cells, tissues and/or organs, resulting in inflammation and damage. There are over 80 different autoimmune diseases, and these range from common to very rare diseases. Some autoimmune diseases affect mainly one part of the body (such as multiple sclerosis, autoimmune thyroid disease, type 1 diabetes) whilst others can affect many parts of the body (such as systemic lupus erythematosus, rheumatoid arthritis and systemic vasculitis).
Autoimmune diseases include common and rare diseases
Autoimmune diseases affect around 1 in 20 people and are one of the most important health issues in Australia and New Zealand. Common autoimmune diseases such as thyroiditis, rheumatoid arthritis and diabetes affect more than 1 in 100 people. In contrast, a rare autoimmune disease such as Goodpasture’s disease (a form of vasculitis) affects around 1 in a million people.
What causes autoimmune diseases?
The exact cause of autoimmune diseases are not yet known. However, in many cases it appears that there is some inherited tendency to develop autoimmune diseases. In people with this inherited tendency, other factors such as infections and some drugs may play a role in triggering autoimmune disease. Other factors include mental and emotional stress, toxic overload as a result of environmental toxins, bacteria, viruses and parasites. Recent research has found a direct link between the brain and the immune system adding further weight to the suggestion that emotional factors may play a role in the activation of poor immune function.
How are autoimmune diseases diagnosed?
Autoimmune diseases are usually diagnosed using a combination of clinical history, blood tests (autoantibodies, inflammation, organ function) and other investigations such as x-rays. Sometimes a biopsy of affected tissues may be required for diagnosis.
What types of autoimmune diseases are there?
There are over 80 different autoimmune diseases and they can be categorised into two general types:
- Localised (organ specific) – affecting mainly one particular part of the body
- Systemic – affecting multiple parts of the body.
These categories may overlap, as localised (organ specific) autoimmune disease can affect other parts of the body and some people may have more than one type of autoimmune disease.
Localised (organ specific) autoimmune diseases
Whilst localised (organ specific) autoimmune diseases mainly affect a single organ or tissue, the effects frequently extend to other body systems and organs. These diseases are often managed by organ-specific Medical Specialists, such as Endocrinologists, Gastroenterologists, Neurologists or Rheumatologists.
Examples of localised (organ specific) autoimmune diseases
- Addison’s disease (adrenal)
- Autoimmune hepatitis (liver)
- Coeliac disease (gastrointestinal tract)
- Crohn’s disease (gastrointestinal tract)
- Diabetes Mellitus Type 1a (pancreas)
- Grave’s disease (thyroid)
- Guillain-Barre syndrome (nervous system)
- Hashimoto’s thyroiditis (thyroid)
- Multiple sclerosis (nervous system)
- Pernicious anaemia (stomach)
- Primary biliary cirrhosis (liver)
- Sclerosing cholangitis (liver)
- Myasthenia gravis (nerves, muscles)
- Ulcerative colitis (gastrointestinal tract)
Systemic autoimmune diseases
Systemic autoimmune diseases can affect many body organs and tissues at the same time. They can be broadly classified into rheumatological/connective tissue disease and vasculitis (inflammation of blood vessels). These diseases are often managed by Clinical Immunologists and/or Rheumatologists.
Examples of rheumatological systemic autoimmune diseases
- Antiphospholipid antibody syndromes (blood cells)
- Dermatomyositis (skin, muscles)
- Mixed connective tissue disease
- Polymyalgia rheumatica (large muscle groups)
- Polymyositis (skin, muscles)
- Primary Raynaud’s disease (blood vessels)
- Rheumatic fever
- Rheumatoid arthritis (joints, less commonly lungs, skin, eyes)
- Scleroderma (skin, intestine, less commonly lungs, kidneys)
- Sjögren’s syndrome (salivary glands, tear glands, joints)
Systemic Lupus Erythematosus (skin, joints, kidneys, heart, brain, red blood cells, other)
Vasculitis disorders are relatively rare and result from inflammation of blood vessels. They have many clinical presentations, sometimes affecting only the skin but not infrequently affecting internal organs. Symptoms include fatigue, weight loss, rashes, sore joints or night sweats. Wegener’s granulomatosis is the most common form of vasculitis and this affects around 5 in a million people.
Examples of vasculitis disorders
VASCULITIS (SMALL BLOOD VESSEL)
- Churg-Strauss syndrome (lungs, skin, nerves)
- Cryoglobulinemia (skin, kidneys, nerves)
- Goodpasture’s syndrome (lungs, kidneys)
- Henoch-Schonlein purpura (skin, joints, kidneys, gut)
- Microscopic polyangiitis (skin, kidneys, nerves)
- Wegener’s granulomatosis (sinuses, lungs, kidneys, skin)
VASCULITIS (MEDIUM BLOOD VESSEL)
- Behcet’s disease (mucous membranes, skin, eyes)
- Central nervous system vasculitis (brain)
- Kawasaki syndrome (skin, mucous membranes, lymph nodes, blood vessels)
- Polyarteritis nodosa (kidneys, gut, nerves, skin)
VASCULITIS (LARGE BLOOD VESSEL)
- Giant cell (temporal) arteritis (arteries of the head and neck)
- Takayasu arteritis (arteries of the head and neck)