Alopecia Areata and Autoimmunity

Alopecia areata results when the body’s immune system attacks healthy hair follicles by mistake. Alopecia areata is often likened to a “swarm of bees” in the form of specific T cells that attack the hair follicle. Normal hair follicles are hidden from immune recognition and enjoy a state of immune privilege or protection from autoimmune attack. The collapse of this immune privilege is what allows the swarm of T cells to attack in alopecia areata. We do not know what activates the autoimmune reaction in alopecia areata but research suggests it is a combination of genetic susceptibility and environmental triggers outside the body, such as bacteria or viruses, which may signal changes that confuse the immune system.