Alopecia is an autoimmune disorder in which the body’s immune system sends signals to white blood cells to attack healthy hair follicle cells. This causes the hair follicles to shrink, resulting in varying degrees of visible hair loss on the scalp and sometimes on the face and body. While there is no known cure for alopecia, the condition can resolve spontaneously. Once the immune system stops attacking the healthy cells, it is possible for hair to grow back during the next hair cycle.
The word alopecia derives from Ancient Greek, which translates roughly to “fox disease,” because foxes shed their fur twice a year. The word areata means “occurring in patches or circumscribed areas.