Autoimmune diseases vary greatly, but each causes the immune system to attack healthy tissue.

Autoimmune diseases can affect almost every body part or system. There are more than 80 of these conditions, and some are more common than others.

Common examples include hypothyroidism, type 1 diabetes, rheumatoid arthritis, lupus, and inflammatory bowel disease (IBD).

The immune system is a network of tissues, organs, and cells. Its role is to defend the body against harmful organisms, such as bacteria and viruses, warding off infection and disease.

In a person with an autoimmune disease, the immune system mistakenly attacks healthy body cells and tissues.

Researchers do not know the causes of many autoimmune conditions, but genetic factors, past infections, and environmental factors can affect their development.

Long-term treatments aim to reduce the strength of immune responses. Antibiotics are not involved because these diseases are not bacterial infections.

This article provides an overview of some common autoimmune conditions. It also describes risk factors, the process of reaching a diagnosis, and treatments.

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Autoimmune diseases are relatively common. According to some estimates, more than 23.5 million people in the United States have at least one autoimmune condition. They are a leading cause of death and disability in the country.

Below, find examples of autoimmune diseases that occur frequently:

Psoriasis

Psoriasis causes the immune system to disrupt the healthy formation of skin cells. This leads to scaly, dry, itchy patches of skin, along with joint pain.

Estimates suggest that more than 8 million people in the U.S. have psoriasis, and it affects 2–3% of the world’s population.

There are many types of psoriasis, each with different symptoms. Some develop more often than others.

Common triggers for psoriasis include stress, infections, and environmental factors.

Hashimoto’s thyroiditis

Hashimoto’s thyroiditis, also called Hashimoto’s disease, is an autoimmune condition in which the immune system attacks cells that create thyroid hormones. This leads to an underactive thyroid, known as hypothyroidism.

Hashimoto’s thyroiditis affects around 5% of people in the U.S. It is at least 8 times more common in females than males.

Symptoms of Hashimoto’s thyroiditis include:

  • a goiter, which is swelling at the front of the neck
  • weight gain
  • tiredness
  • depression
  • joint and muscle pain
  • increased sensitivity to cold
  • a slowed heart rate
  • heavy or irregular menstruation

Graves disease

Graves disease is an autoimmune condition that causes the thyroid gland to produce too much thyroid hormone. This leads to hyperthyroidism.

Graves disease affects about 1 in 200 people. It is more common in females than males.

Symptoms of Graves disease include:

  • nervousness or anxiety
  • fatigue
  • a rapid, irregular heartbeat
  • shaky hands
  • high blood pressure
  • sweating and difficulty tolerating hot conditions
  • weight loss
  • light, irregular menstruation
  • a goiter

IBD

IBD is a long-term digestive condition. In a person with IBD, an immune system response to environmental triggers leads to inflammation in the stomach and gut.

The condition may affect around 1.3% of adults in the U.S., or around 3 million people.

There are two main types of IBD:

  • Crohn’s disease, which involves chronic inflammation occurring anywhere from the mouth to end of the large intestine
  • ulcerative colitis, which involves long-term inflammation of the large intestine

Symptoms of IBD include:

  • stomach pain
  • bloating
  • persistent diarrhea
  • blood in stool
  • weight loss
  • fatigue

Celiac disease

Celiac disease is an immune disorder that causes the lining of the small intestine to become inflamed after the person eats foods that contain gluten.

It can lead to abdominal pain, an inability to absorb key nutrients, and some other symptoms, such as joint pain and characteristic rashes.

The immune response is genetically determined and is aimed at gliadin, a component of gluten.

Gluten is a protein in wheat, rye, and barley. Eliminating it from the diet helps control the signs and symptoms of celiac disease.

As many as 1 in 141 people in the U.S. may have celiac disease, though many of them may be unaware.

When a person with the condition eats gluten, their immune system attacks healthy tissue in the small intestine. Over time this damages the organ, preventing it from absorbing nutrients properly.

Symptoms of celiac disease include:

Celiac disease is different from gluten intolerance or sensitivity. Either of these issues can cause symptoms similar to those of celiac disease, but there is no damage to the digestive system.

Systemic lupus erythematosis

Systemic lupus erythematosis (SLE) refers to a range of conditions marked by inflammation of the skin, joints, and — when severe — internal organs.

Lupus affects around 1.5 million people in the U.S. and 5 million people worldwide. Most people with lupus are female.

Symptoms of SLE include:

  • muscle and joint pain
  • a butterfly-shaped rash on the face
  • sun sensitivity
  • tiredness
  • a fever

Rheumatoid arthritis

Rheumatoid arthritis is one of the most common long-term autoimmune disorders. It causes the immune system to attack healthy tissue in the joints, including those of the hands, wrists, and knees.

About 1.3 million adults in the U.S. have this condition, which is two to three times more common in females than in males.

Symptoms of rheumatoid arthritis include:

  • pain, tenderness, and swelling around the joints
  • joint stiffness
  • symptoms that appear on both sides of the body, such as on both hands or knees
  • weight loss
  • fatigue
  • weakness

Type 1 diabetes

Type 1 diabetes causes the immune system to destroy cells in the pancreas that create insulin, called beta cells. As a result, the pancreas is less able to make insulin, leading to insulin deficiency.

Not having enough insulin means that sugars cannot be transported around the body properly, leading to high blood sugar levels.

About 1 in 300 people in the U.S. have type 1 diabetes by age 18. Symptoms include:

  • frequent urination
  • increased thirst
  • a loss of energy
  • blurred vision
  • hunger
  • nausea

Autoimmune diseases can develop in anyone, but certain factors increase the risk.

The risk factors vary among the many types of autoimmune disease, but some common factors include:

  • Genetics: Some autoimmune conditions run in families. A person might inherit genes that predispose them to a condition but only develop it when exposed to a combination of triggers.
  • Environmental factors: Sunlight, certain chemicals, and viral or bacterial infections can all affect the development of autoimmune conditions.
  • Sex: More females have autoimmune disorders than males, due to hormonal factors. The disorders often develop during childbearing years.
  • Race: This appears to play a role in the diagnosis and severity of certain autoimmune diseases. For example, more white people receive a diagnosis of type 1 diabetes, while lupus is more severe in African American and Hispanic people.
  • Other autoimmune conditions: A person with one autoimmune disorder has an increased risk of developing another.

The symptoms of autoimmune conditions tend to be general, overlapping with symptoms of other issues, particularly other autoimmune disorders. This can make it challenging to accurately diagnose an autoimmune condition.

For example, lupus can affect the joints similarly to rheumatoid arthritis, but the symptoms tend to be less severe. IBD causes similar symptoms to celiac disease, but IBD is not typically caused by consuming gluten.

Also, the diagnostic process differs, depending on the specific disease.

However, it usually involves blood tests. A doctor can often diagnose an autoimmune disease by analyzing antibodies produced by the immune system.

A test called a complete blood count allows the doctor to check the levels of white and red blood cells in the body. When the immune system is fighting off something, the levels are different from the usual baseline.

Often, simple blood tests can indicate various conditions. For instance, diagnosing Hashimoto’s thyroiditis and Graves’ disease requires a simple test to measure levels of thyroid hormone.

Other tests can indicate unusual inflammation — an issue that is fairly common among all autoimmune diseases. These tests include a C-reactive protein test and an erythrocyte sedimentation rate test.

For some people, getting a diagnosis can be a long process. Experts recommend:

  • writing out a family health history
  • recording the symptoms over time
  • seeing a specialist
  • asking for second, third, and fourth opinions, if necessary

If a doctor says or implies that the symptoms are stress-related or imagined, see another doctor.

While there is no cure for any autoimmune condition, treatments can reduce or eliminate symptoms, slow the progression of the illness, and improve the quality of life.

Specific approaches vary by condition, but common treatments include:

Relieving symptoms

This might involve taking aspirin or ibuprofen to reduce mild pain and swelling or prescribed alternatives, depending on the severity of the symptoms.

Prescribed medications can also help with:

  • depression
  • anxiety
  • fatigue
  • sleep problems
  • rashes

In many cases, getting regular exercise and having a balanced, nutritious diet can also help.

Taking replacement drugs

Some autoimmune disorders affect the body’s ability to produce what it needs. For instance, type 1 diabetes keeps the body from creating enough insulin, and thyroid disease prevents it from producing the right amount of thyroid hormone.

Various medications can replace these substances. A person may have insulin injections or take pills that contain synthetic versions of thyroid hormone.

Taking immunosuppressants

For many people, medications that suppress the immune system can relieve the symptoms of an autoimmune disorder and slow its progression.

However, these drugs, called immunosuppressants, can cause side effects.

Avoiding triggers

In some cases, avoiding things that trigger the immune system reaction can help ease or eliminate symptoms and slow down the progression of the disease.

For example, having a gluten-free diet can prevent symptoms of celiac disease.

There are many types of autoimmune disease, and their symptoms can overlap. This may make it difficult to get an accurate diagnosis.

Autoimmune conditions are a leading cause of disability and death in the U.S. Anyone who believes that they may have one should contact a doctor.