What is an autoimmune disease?
The immune system Overview of the Immune System The immune system is your body's defense system. It helps protect you from illness and infection. The immune system's job is to attack things that don’t belong in your body, including: Germs... read more is your body's defense system. It helps protect you from illness and infection. The immune system usually attacks invading bacteria, viruses, and cancer cells. With an autoimmune disease, your immune system attacks your own body.
There are many different autoimmune diseases
Symptoms of autoimmune diseases are different depending on which disease you have and what part of your body is affected
Doctors do blood tests to check for an autoimmune disease
Doctors treat autoimmune diseases with medicines that slow down the immune system
Autoimmune diseases may attack almost any part of your body:
Skin (lupus, bullous pemphigoid Bullous Pemphigoid Bullous pemphigoid is an autoimmune disease that causes blistering of the skin. Bullous pemphigoid is an autoimmune disorder that occurs when the immune system attacks the skin and causes blistering... read more
, or pemphigoid vulgaris Pemphigus Vulgaris Pemphigus vulgaris is a rare, severe autoimmune disorder in which blisters of varying sizes break out on the skin and on the lining of the mouth and other mucous membranes. Pemphigus vulgaris... read more
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What causes an autoimmune disease?
Your immune system attacks your healthy tissues. Here’s how it works:
Usually, your immune system protects your body from illness by attacking substances (such as bacteria or viruses) that are dangerous or unhealthy
In autoimmune diseases, your immune system mistakes healthy parts of your body for an attacking substance
Your immune system then attacks your healthy cells or tissues just like they were something that would make you sick
This causes the symptoms of an autoimmune disease

Some people are more likely to have an autoimmune disease because it runs in their family.
Women are more likely than men to have an autoimmune disease.
What are the symptoms of an autoimmune disease?
Symptoms are different depending on which disease you have and what part of your body is affected. However, in general, autoimmune diseases cause swelling and tissue damage. You may have one or more of these symptoms:
Painful joints
Swollen, red joints
Itching
Other autoimmune diseases may cause difficulty breathing, jaundice Jaundice in Adults Jaundice is a yellow color to your skin and the whites of your eyes. Jaundice is caused by a buildup of a substance called bilirubin Bilirubin is a yellow substance your body makes when it breaks... read more (yellow skin and eyes), weakness, and confusion. You may develop kidney failure Chronic Kidney Disease Your kidneys are 2 bean-shaped organs that produce urine. They're about the size of your fist and are in the back of your abdomen, near your spine. Kidneys balance your body’s water and mineral... read more .
Sometimes, an autoimmune disease may cause death.
How can doctors tell if I have an autoimmune disease?
If doctors suspect an autoimmune disease, they’ll ask about your symptoms, examine you, and do blood tests.
How do doctors treat an autoimmune disease?
Doctors usually:
Give you medicines that slow down your immune system and its attack on your body
The most common medicines doctors use are corticosteroids, such as prednisone. Sometimes doctors use stronger medicines to slow down your immune system.
The downside of these medicines is they also make it harder for your body to fight off infection. Some of the medicines also can increase your risk of cancer. Your doctor will watch you closely to help protect you from getting another sickness.
Most autoimmune diseases are long term, and people who have them often need to take medicine for the rest of their lives.