Sometimes migrains can be caused but odd things. Years ago I got a flu shot. For the next year and a half I got a migrain if I ate anything with a lot of eggs in it or if I ate an egg. Mine were so bad that I kept a heavy quilt on my curtain rod, pulled back when I didn't need it, and a bucket by the bed. After the flu shot wore off I haven't had a migrain since and can once again eat eggs. Has anything changed in her life lately? New meds? Flu or Pnumonia shots? Stress levels? No matter what it is, she should see a doctor.