An autoimmune disorder occurs when the body's immune system attacks and destroys healthy body tissue by mistake. There are more than 80 types of autoimmune disorders.
The blood cells in the body's immune system help protect against harmful substances. Examples include bacteria, viruses, toxins, cancer cells, and blood and tissue from outside the body. These substances contain antigens. The immune system produces antibodies against these antigens that enable it to destroy these harmful substances.
When you have an autoimmune disorder, your immune system does not distinguish between healthy tissue and potentially harmful antigens. As a result, the body sets off a reaction that destroys normal tissues.
The exact cause of autoimmune disorders is unknown. One theory is that some microorganisms (such as bacteria or viruses) or drugs may trigger changes that confuse the immune system. This may happen more often in people who have genes that make them more prone to autoimmune disorders.
An autoimmune disorder may result in:
An autoimmune disorder may affect one or more organ or tissue types. Areas often affected by autoimmune disorders include:
A person may have more than one autoimmune disorder at the same time. Common autoimmune disorders include:
Symptoms will vary, based on the type and location of the faulty immune response. Common symptoms include:
The health care provider will do a physical exam. Signs depend on the type of disease.
Tests that may be done to diagnose an autoimmune disorder include:
The goals of treatment are to:
Treatments will depend on your disease and symptoms. Types of treatments include:
Many people take medicines to reduce the immune system's abnormal response. These are called immunosuppressive medicines. Examples include corticosteroids (such as prednisone) and nonsteroid drugs such as azathioprine, cyclophosphamide, mycophenolate, sirolimus, or tacrolimus. Targeted drugs such as tumor necrosis factor (TNF) blockers and Interleukin inhibitors can be used for some diseases.
The outcome depends on the disease. Most autoimmune diseases are chronic, but many can be controlled with treatment.
Symptoms of autoimmune disorders can come and go. When symptoms get worse, it is called a flare-up.
Complications depend on the disease. Medicines used to suppress the immune system can cause severe side effects, such as higher risk for infections.
Call your provider if you develop symptoms of an autoimmune disorder.
There is no known prevention for most autoimmune disorders.
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Reviewed By: David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team. Editorial update 09/29/2021.