It sounds as if she has the more frequent type that is acquired in late adulthood. It is rare for it to be universal when acquired late, though. People will sometimes spontaneously re-pigment, too. My loss is universal over my skin, and I have a huge white streak where my hair naturally parts in the front. I'm certain that is the beginning of total loss of pigment in my hair. My cousins all have partial pigmentation with spots on their faces (the typical racoon type marking with pigment being lost in a mask shape around the eyes) and lesions on stressor points like knees and elbow.
Mine began when I was about 2 and fell and scraped a knee. After it healed, the pigment was gone, and the margins began spreading outward from there. Next spots began to appear on stressor points with margins spreading from the initial lesion. By 18, I had lost all pigment from the elbows down, and all pigment from the knees down. By 25, only pigment remained on my torso. After the birth of my son, the rest said bye-bye.
My brother's began the same as mine, but at around the age of 12, he started to spontaneously re-pigment, and as an adult, retained only one lesion on his left knee and the same white streak I have in his hair. No one has ever been able to explain the difference in manifestation.