Alopecia areata is a common autoimmune disorder that often results in unpredictable hair loss. In the majority of cases, hair falls out in small patches around the size of a quarter. For most people, hair loss is nothing more than a few patches, though in some cases it can be more extreme. Sometimes, it can lead to the complete loss of hair on the scalp (Alopecia Totalis) or, in extreme cases, the entire body (Alopecia Universalis). The condition can affect anyone regardless of age and gender, though most cases occur before the age of 30.