I lost my hair completely in my early 20's (1980's). It all started with I thought, normal hair loss and escalated to several balding spots all over and then completely lost all my hair. I never thought I would ever have hair again. I guess it's called alopecia areata ... Consulted with several doctors - and the causes can vary .... in my case, it's stress.
Fortunately, I listened to my aunt who suggested I should use fresh aloe vera and apply it twice a day all over my scalp.... It took months but it worked!!!
I still exprerience hair loss when I am under stress ... I am just thankful that I still have hair... more than most people.