Autoimmune diseases are a group of illnesses that occur when the body’s immune system mistakenly attacks its own cells and tissues. Symptoms of autoimmune diseases vary greatly from person to person and can also vary over time. Common symptoms include fatigue, muscle aches, joint pain, difficulty concentrating and/or skin rashes. Diagnosis of autoimmune diseases is often difficult as symptoms can be vague and overlap with other conditions. Diagnostic tests such as blood tests, imaging tests, and biopsies may be necessary to make a diagnosis. Treatment for autoimmune diseases typically includes medications such as immunosuppressants, corticosteroids, and/or biologics, as well as lifestyle modifications such as dietary changes, stress reduction, and exercise.