Simple, Important Questions & Answers about Autoimmune Diseases (I)

What Is Autoimmunity?

When your body is attacked—perhaps by a virus or germs on a nail you stepped on—your immune system defends you. It sees and kills the germs that might hurt you.

But when the system doesn’t work right, this process can cause harm. Immune cells can mistake your body’s own cells as invaders and attack them. This “friendly fire” can affect almost any part of the body. It can sometimes affect many parts of the body at once. This is called autoimmunity (meaning self-immunity).

What Causes Autoimmunity?

No one knows why the immune system treats some body parts like germs. We do know that you can’t catch autoimmune diseases from another person.

Most scientists think that our genes and things in the environment are involved. If you have a certain gene or combination of genes, you may be at higher risk for autoimmune disease. But you won’t get the disease until something around you turns on your immune system. This may include the sun, infections, drugs, or, in some women, pregnancy.

What Kinds of Problems Are Caused by Autoimmunity?

Autoimmunity can affect almost any organ or body system. The exact problems one has with autoimmunity (or its diseases) depends on which tissues are targeted.

If the skin is the target, you may have skin rashes, blisters, or color changes. If it’s the thyroid gland, you may be tired, gain weight, be more sensitive to cold, and have muscle aches. If it’s the joints, you may have joint pain, stiffness, and loss of function.

You may know which organ or system is affected from the start. But you may not know the site of the attack. In many people, the first symptoms are fatigue, muscle aches, and low fever.

Where Does Autoimmunity Strike?

Because autoimmune diseases can affect almost any organ or system of the body, one way to group them is by the body system(s) they attack. The following is a list (not inclusive) of body systems and the autoimmune diseases that can affect them:

Blood and blood vessels

  • Autoimmune hemolytic anemia
  • Pernicious anemia
  • Polyarteritis nodosa
  • Systemic lupus erythematosus
  • Wegener’s granulomatosis

Digestive tract (including the mouth)

  • Autoimmune hepatitis
  • Behçet’s disease
  • Crohn’s disease
  • Primary bilary cirrhosis
  • Scleroderma
  • Ulcerative colitis


  • Sjögren’s syndrome
  • Type 1 diabetes mellitus
  • Uveitis


  • Graves’ disease
  • Thyroiditis
  • Type 1 diabetes mellitus


  • Myocarditis
  • Rheumatic fever
  • Scleroderma
  • Systemic lupus erythematosus


  • Ankylosing spondylitis
  • Rheumatoid arthritis
  • Systemic lupus erythematosus


  • Glomerulonephritis
  • Systemic lupus erythematosus
  • Type 1 diabetes mellitus


  • Rheumatoid arthritis
  • Sarcoidosis
  • Scleroderma
  • Systemic lupus erythematosus


  • Dermatomyositis
  • Myasthenia gravis
  • Polymyositis

Nerves and brain

  • Guillain-Barré syndrome
  • Multiple sclerosis
  • Systemic lupus erythematosus


  • Alopecia areata
  • Pemphigus/pemphigoid
  • Psoriasis
  • Scleroderma
  • Systemic lupus erythematosus
  • Vitiligo


National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS)

National Institutes of Health 

U.S. Department of Health and Human Services

Public Health Service

Facebook Comments

1 Comment

  1. Unquestionably believe that which you said. Your favorite reason appeared to be on the web the simplest thing to be aware of. I say to you, I certainly get irked while people consider worries that they just don’t know about. You managed to hit the nail upon the top and defined out the whole thing without having side effect , people can take a signal. Will likely be back to get more. Thanks

Leave a Reply