Alopecia is the medical term for baldness; there are various types of alopecia; Alopecia areata is a condition that causes a person's hair to fall out. It is an autoimmune disease; that is, the person's immune system attacks their own body. In this case, their hair follicles. When this happens, the person's hair begins to fall out, often in clumps the size and shape of a quarter. This is named Alopecia Areata. The extent of the hair loss varies; in some cases, it is only in a few spots. In others, the hair loss can be greater.
Alopecia Totalis: is most hair on a person head is lost
Alopecia Universalis: usually affects the entire body
It is believed that the person's genetic makeup may trigger the autoimmune reaction of alopecia areata, along with other unknown triggers.
Alopecia areata is an unpredictable disease. In some people, hair grows back but falls out again later. In others, hair grows back and remains. Each case is unique. Even if someone loses all of his or her hair, there is a chance that it will grow back.