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, the 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. Fast facts on alopecia areata Here are some key points about alopecia areata. One in five people with alopecia areata also has a family member who has experienced the condition. Alopecia areata often develops suddenly, over the course of just a few days. There is little scientific evidence that alopecia areata is caused by stress. Full recovery is possible.