What is alopecia areata? Alopecia areata is a disease that causes hair loss. In alopecia areata, the immune system attacks the structures in skin that form hair (hair follicles). Alopecia areata usually affects the head and face, though hair can be lost from any part of the body. Hair typically falls out in small, round patches about the size of a quarter. In some cases, hair loss is more extensive.
The FDA approved Olumiant (baricitinib) oral tablets to treat adult patients with severe alopecia areata. The action marks the first FDA approval of a systemic treatment (i.e. treats the entire body rather than a specific location) for alopecia areata.