4 minute read

Demystifying autoimmune diseases: triggers, symptoms, and types

Published March 2, 2024

Your immune system serves as your body’s built-in bodyguard. It helps keep you healthy by fighting off harmful substances like viruses, bacteria, and toxins. But what happens when the bodyguard turns against the very thing it was designed to protect—accidentally attacking the body rather than protecting it?

What is an autoimmune disease? 

Your immune system functions as your body’s built-in bodyguard. It works around the clock to protect you from harmful threats. When it detects a threat (like a germ), it responds by sending out special cells. These cells work together to stop the threat, clean up the mess, and stand guard to prevent future attacks. But the immune system doesn’t just fight off germs—it also remembers them. So, if the same germ tries to attack again, the immune system knows how to stop it.¹

But sometimes the immune system makes a mistake. Instead of targeting harmful invaders, it makes a critical error, treating healthy parts of your body (like skin, joints, or organs) as enemies. This mistake triggers inflammation (swelling and irritation) and can damage healthy tissues, leading to symptoms and health conditions like autoimmune diseases.²

What triggers the immune system to turn against the body, leading to autoimmune diseases?

Scientists don't fully understand what causes autoimmune diseases. But here's what they do know²:

  • They aren’t contagious, so you can't catch them from someone else
  • Having a family member with an autoimmune disease increases your risk of developing one
  • Having an autoimmune disease increases your risk of developing another one

Other risk factors include[² ³]:

  • Being female (roughly 75% of those affected are female)
  • Certain medications
  • Smoking
  • Obesity
  • Exposure to certain toxins, chemicals, or infections

►Having 1 or more risk factors doesn't mean you'll develop an autoimmune disease, but it can increase your chances. If you have questions about your risk, please talk with your doctor.

What’s the difference between antibodies and autoantibodies?

Your immune system makes proteins called antibodies to fight off invaders like viruses and bacteria. Their job is to help keep you healthy. But in some cases, the immune system mistakenly creates proteins called autoantibodies. Unlike regular antibodies, autoantibodies attack healthy cells and organs in the body as if they were harmful, leading to inflammation and damage.⁴

What’s the difference between IgM and IgG?

When your immune system senses a threat, it fights back by making antibodies called immunoglobulins (pronounced im-mew-no-glob-you-lins). IgG and IgM are both antibodies, but they do have some differences.

When your body encounters a foreign antigen, like a virus or bacteria, your immune system kicks into gear by producing IgM antibodies. These antibodies act as the first responders, alerting your body to the threat. An antigen is a substance that triggers your immune system to react. This could be a germ, toxin, or even something normally in your body that the immune system sees as a threat. IgM antibodies provide short-term protection while your body ramps up production of other antibodies to help fight off the threat.⁵

Most of the antibodies circulating in your blood are IgG. Unlike other antibodies, IgG can travel throughout your body fluids, offering protection in various tissues. Your body remembers all the IgG antibodies you’ve made. That way, if the same antigen tries to attack again—your immune system can quickly make more antibodies to fight it off.⁵

What are the different types of autoimmune diseases?

There are many (over 100) autoimmune diseases that can affect different parts of the body. Below are only a few examples³:

  • Rheumatoid arthritis (widespread)
  • Lupus (widespread)
  • Graves’ disease (thyroid gland)
  • Type 1 diabetes (pancreas)
  • Hashimoto’s thyroiditis (thyroid gland)
  • Celiac disease (small intestine)
  • Pernicious anemia (stomach)

What’s rheumatoid arthritis? How is it different from other autoimmune diseases or forms of arthritis?

Rheumatoid arthritis is a long-term autoimmune disease that causes the body to attack healthy cells instead of bacteria or viruses. This can cause painful inflammation, especially in the joints (hands, wrists, knees), but it can also affect organs like the eyes, lungs, and heart. As the disease progresses, joints can become damaged, leading to ongoing pain and mobility challenges.⁶

Unlike some autoimmune diseases that focus on specific parts of the body, rheumatoid arthritis can attack many joints at once and even affect other areas. It's also different from "regular arthritis" (osteoarthritis) which is caused by wear and tear, not an attack by the body's own immune system.

How does an autoimmune disease impact a person’s daily life and overall health? 

There are many types of autoimmune diseases, and each affects the body differently. For instance, someone living with rheumatoid arthritis might feel pain and stiffness in their joints, while someone living with Crohn's disease could have stomach pain and diarrhea. 

Symptoms can also range from mild to severe. Some people might have symptoms that come and go, while others have ongoing (chronic) symptoms that impact their daily lives. Depending on which part of the body is affected, symptoms can look different. Some examples include²:

  • Muscle aches, pains, or weakness
  • Joint pain, stiffness, or swelling
  • Inflammation
  • Bloating
  • Stomach pain
  • Constipation, diarrhea, or bloody stools
  • Nausea (feeling sick)
  • Rashes
  • Dry eyes, mouth, or skin
  • Hair loss
  • Dizziness
  • Headaches or migraines
  • Blurry vision
  • Fever
  • Fatigue
  • Weight gain or loss
  • Anxiety or depression
  • Brain fog
  • Sleep issues
  • Memory issues

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  1. Medline Plus. Autoimmune diseases. Accessed February 28, 2024. https://medlineplus.gov/autoimmunediseases.html 
  2. Cleveland Clinic. Autoimmune diseases. Accessed February 28, 2024. https://my.clevelandclinic.org/health/diseases/21624-autoimmune-diseases 
  3. American Autoimmune Related Diseases Association (AARDA). Autoimmune facts. Accessed February 28, 2024. https://autoimmune.org/wp-content/uploads/2019/12/1-in-5-Brochure.pdf
  4. Britannica. Autoantibody. Accessed February 28, 2024. https://www.britannica.com/science/autoantibody 
  5. Medline Plus. Immunoglobulins blood test. Accessed February 28, 2024. https://medlineplus.gov/lab-tests/immunoglobulins-blood-test/ 
  6. Centers for Disease Control and Prevention (CDC). Rheumatoid arthritis. Accessed February 28, 2024. https://www.cdc.gov/arthritis/types/rheumatoid-arthritis.html