Why does the immune system attack the body?
Doctors don’t know exactly what causes the immune system to 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% of women versus 2.7% of men. The disease often starts during childbearing age (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 white people.
Certain autoimmune diseases, such as 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 are thought to be linked to inflammation, which might set off an immune response. But this hasn’t been proven.
14 common autoimmune diseases
There are more than 80 autoimmune diseases. Here are 14 of the most common ones.
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 damage the blood vessels and organs, including 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 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 lighter-toned skin. On darker skin, psoriasis can appear purplish or dark brown with gray scales.
Up to 30% 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 surrounding 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 numbness, weakness, balance issues, and trouble walking. The disease comes in several forms that progress at different rates. According to a 2012 study:
About 50% 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 common, actually affects many organs, including the joints, kidneys, brain, and heart.
Joint pain, fatigue, and rashes are among the most common symptoms
6. Inflammatory bowel disease
Inflammatory bowel disease (IBD) describes conditions that cause inflammation in the lining of the intestinal wall. Each type of IBD affects a different part of the GI tract.
- Crohn’s disease can inflame any part of the GI tract, from the mouth to the anus.
- Ulcerative colitis affects only the lining of the large intestine (colon) and rectum.
7. Addison’s disease
Addison’s disease affects the adrenal glands, which produce the hormones cortisol and aldosterone as well as androgen hormones. Too little cortisol can affect how the body uses and stores carbohydrates and sugar (glucose). Deficiency of aldosterone will lead to sodium loss and excess potassium in the bloodstream.
Symptoms include weakness, fatigue, weight loss, and low blood sugar.
8. Graves’ disease
Graves’ disease attacks the thyroid gland in the neck, causing it to produce too much of its hormones. Thyroid hormones control the body’s energy usage, known as metabolism.
Having too much of these hormones revs up your body’s activities, causing symptoms like nervousness, a fast heartbeat, heat intolerance, and weight loss.
One potential symptom of this disease is bulging eyes, called exophthalmos. It can occur as a part of Graves’ ophthalmopathy, which occurs in around 30% of those with Graves’ disease,
9. Sjögren’s syndrome
This condition attacks the glands that provide lubrication to the eyes and mouth. The hallmark symptoms of Sjögren’s syndrome are dry eyes and dry mouth, but it may also affect the joints or skin.
10. Hashimoto’s thyroiditis
In Hashimoto’s thyroiditis, thyroid hormone production slows to a deficiency. Symptoms include weight gain, sensitivity to cold, fatigue, hair loss, and swelling of the thyroid (goiter).
11. Myasthenia gravis
Myasthenia gravis affects nerve impulses that help the brain control the muscles. When the communication from nerves to muscles is impaired, signals can’t direct the muscles to contract.
The most common symptom is muscle weakness, which worsens with activity and improves with rest. Muscles that control eye movements, eyelid opening, swallowing, and facial movements are often involved.
12. Autoimmune vasculitis
Autoimmune vasculitis happens when the immune system attacks blood vessels. The inflammation that results narrows the arteries and veins, allowing less blood to flow through them.
13. Pernicious anemia
This condition causes a deficiency of a protein made by stomach lining cells, which is an intrinsic factor needed for the small intestine to absorb vitamin B12 from food. Without enough of this vitamin, one will develop anemia, and the body’s ability for proper DNA synthesis will be altered.
Pernicious anemia is more common in older adults. According to a 2012 study, it affects 0.1% of people in general but nearly 2% of people over age 60.
14. Celiac disease
People with celiac disease can’t eat foods containing gluten, a protein found in wheat, rye, and other grain products. When gluten is in the small intestine, the immune system attacks this part of the gastrointestinal tract and causes inflammation.
A 2015. Study noted that celiac disease affects about 1% of people in the United States. Many people have reported gluten sensitivity, which isn’t an autoimmune disease but can have similar symptoms such as diarrhea and abdominal pain.