Allergies and autoimmune diseases both involve the immune system, but what differentiates them is the way the autoimmune system reacts, and what gets targeted as a result.
What is an allergy?
An allergy occurs when the immune system overreacts to a normally harmless substance, producing an IgE antibody that triggers an exaggerated response with the release of histamines from mast cells and basophils. This can lead to acute episodes of itching, swelling, difficulty swallowing, or difficulty breathing.
What is an autoimmune disease?
An autoimmune disease occurs when cells of the immune system produces autoantibodies that mark the body’s own cells and tissues for destruction by other cells of the immune system. The reasons for doing this are not completely clear – genetics, environment, diet are all possible causes. The destruction of cells and tissues by the immune system leads to chronic inflammation, irritation, swelling, and itching.
Is coeliac disease an intolerance, allergy, or autoimmune disease?
Coeliac disease is an autoimmune disease. It is diagnosed by the presence of autoantibodies in the blood that the immune system uses to mark areas of the small intestine to be destroyed in response to contact with gluten, because it falsely believes that the small intestine is a danger to the rest of the body. Sounds inconvenient? It truly is! While the “cure” for coeliac disease is avoidance of gluten, there is not usually an allergic reaction associated with the gluten.
Are there any autoimmune diseases that could be causing my rash?
Absolutely – systemic lupus erythematosus (SLE or Lupus) is one example, with a butterfly-shaped rash appearing over the face, often in response to sunlight, making it appear to be a sunlight allergy. Psoriasis, Sjogren’s syndrome, rheumatoid arthritis, coeliac disease, scleroderma, and vasculitis are other examples of autoimmune diseases that may present with rashes. Kate Knowler is part of our advisory board and has written a book on this topic which you can view for yourself here.
What about my itchy eyes? That must be an allergy, surely?
Sjogren’s syndrome is an autoimmune disease associated with dry mucous membranes – the eyes, mouth, nose, throat, skin, and even vaginal tissues in females. So your itchy eyes might be hayfever or another allergy, but might also be Sjogren’s.
Sometimes my lips and throat can swell up. Is that an allergy?
In many cases, this is an allergy and should be considered an emergency – ring 999 and say “anaphylaxis” if this ever happens to you or someone you are with, regardless of other diagnoses that they may have. But, autoimmune angioedema is known to cause swelling beneath the skin around the eyes, lips, and throat, mimicking allergy symptoms and anaphylaxis. If symptoms tend to be more chronic, and less triggered by consumption/contact with food, then autoimmune angioedema should be ruled out.
How can I find out if I have an allergy or an autoimmune disease?
The best way to differentiate between an allergy or an autoimmune disease is to get an Allergy Test. Allergy testing for IgE antibodies helps to rule out specific allergies, while blood tests for ANA (anti-nuclear antibodies) are the first step to testing for autoimmune diseases. Confusingly, not everyone with an autoimmune disease will have a raised ANA, and not everyone with a raised ANA will have an autoimmune disease. For this reason, it is important to assess your symptoms as well as your test results, and a rheumatologist is the expert to seek advice from when it comes to diagnosing autoimmune disease. Grab a test today and uncover your hidden allergies.
