An autoimmune disease is a disorder in which the body's immune system mistakenly attacks and destroys the body's own healthy tissue. Normally, the immune system protects the body against foreign pathogens, such as viruses and bacteria, but in an autoimmune disease, the immune system attacks the body's cells, tissues, and organs as if they were foreign invaders. Autoimmune diseases can affect any part of the body and there are more than 80 different types. Symptoms of autoimmune diseases can vary depending on the type of disease and the part of the body affected, but can include fatigue, pain, inflammation, fever, and skin problems, among others.
Prevalence percentages of autoimmune diseases vary depending on the populations and data sources used. A general estimate of global prevalence percentages for some of these diseases is provided below:
