A Long-Term Study to Learn About The Study Medicine Called Ritlecitinib in Children With Severe Alopecia Areata.

A Study in Young People and Adults to Learn About the Medicine Ritlecitinib for Treatment of Patchy Hair Loss, Known by the Medical Term as Moderate Alopecia Areata

A Study to Learn About Litfulo Capsule in People With Severe Alopecia Areata in Routine Clinical Practice.