An autoimmune disease is a condition in which your immune system mistakenly attacks your body.
The immune system normally guards against germs like bacteria and viruses. When it senses these foreign invaders, it sends out an army of fighter cells to attack them.
Normally, the immune system can tell the difference between foreign cells and your own cells.
In an autoimmune disease, the immune system mistakes part of your body, like your joints or skin, as foreign. It releases proteins called autoantibodies that attack healthy cells.
Some autoimmune diseases target only one organ. Type 1 diabetes damages the pancreas. Other diseases, like systemic lupus erythematosus (SLE), affect the whole body.
Why does the immune system attack the body?
Doctors don’t know exactly what causes the immune-system misfire. Yet some people are more likely to get an autoimmune disease than others.
According to a 2014 study, women get autoimmune diseases at a rate of about 2 to 1 compared to men — 6.4 percent of women vs. 2.7 percent of men. Often the disease starts during a woman’s childbearing years (ages 15 to 44).
Some autoimmune diseases are more common in certain ethnic groups. For example, lupus affects more African-American and Hispanic people than Caucasians.
Certain autoimmune diseases, like multiple sclerosis and lupus, run in families. Not every family member will necessarily have the same disease, but they inherit a susceptibility to an autoimmune condition.
Because the incidence of autoimmune diseases is rising, researchers suspect environmental factors like infections and exposure to chemicals or solvents might also be involved.
A “Western diet” is another suspected risk factor for developing an autoimmune disease. Eating high-fat, high-sugar, and highly processed foods is thought to be linked to inflammation, which might set off an immune response. However, this hasn’t been proven.
common autoimmune diseases
1. Type 1 diabetes
The pancreas produces the hormone insulin, which helps regulate blood sugar levels. In type 1 diabetes mellitus, the immune system attacks and destroys insulin-producing cells in the pancreas.
High blood sugar results can lead to damage in the blood vessels, as well as organs like the heart, kidneys, eyes, and nerves.
2. Rheumatoid arthritis (RA)
In rheumatoid arthritis (RA), the immune system attacks the joints. This attack causes redness, warmth, soreness, and stiffness in the joints.
Unlike osteoarthritis, which commonly affects people as they get older, RA can start as early as your 30s or sooner.
3. Psoriasis/psoriatic arthritis
Skin cells normally grow and then shed when they’re no longer needed. Psoriasis causes skin cells to multiply too quickly. The extra cells build up and form inflamed red patches, commonly with silver-white scales of plaque on the skin.
Up to 30 percent of people with psoriasis also develop swelling, stiffness, and pain in their joints. This form of the disease is called psoriatic arthritis.
4. Multiple sclerosis
Multiple sclerosis (MS) damages the myelin sheath, the protective coating that surrounds nerve cells, in your central nervous system. Damage to the myelin sheath slows the transmission speed of messages between your brain and spinal cord to and from the rest of your body.
This damage can lead to symptoms like numbness, weakness, balance issues, and trouble walking. The disease comes in several forms that progress at different rates. According to a 2012 study Trusted Source, about 50 percent of people with MS need help walking within 15 years after the disease starts.
5. Systemic lupus erythematosus (SLE)
Although doctors in the 1800s first described lupus as a skin disease because of the rash it commonly produces, the systemic form, which is most the common, actually affects many organs, including the joints, kidneys, brain, and heart.
Joint pain, fatigue, and rashes are among the most common symptoms.
Autoimmune disease symptoms
The early symptoms of many autoimmune diseases are very similar, such as:
- achy muscles
- swelling and redness
- low-grade fever
- trouble concentrating
- numbness and tingling in the hands and feet
- hair loss
- skin rashes
Tests that diagnose autoimmune diseases
No single test can diagnose most autoimmune diseases. Your doctor will use a combination of tests and a review of your symptoms and physical examination to diagnose you.
The antinuclear antibody test (ANA) is often one of the first tests that doctors use when symptoms suggest an autoimmune disease. A positive test means you may have one of these diseases, but it won’t confirm exactly which one you have or if you have one for sure.
Other tests look for specific autoantibodies produced in certain autoimmune diseases. Your doctor might also do nonspecific tests to check for the inflammation these diseases produce in the body.