have you tried paw paw cream? I'm assuming you use no soap products, nothing from johnson and johnson, I'm currently trying curash in the bath. I got a ointment from the doctor but only use it once a day because it's great stuff. Someone when I was doing research on this site said to help the baby sleep they used a gentle lufer(?) to help with the itch. I started making most of my own baby food and I try not to overheat Lilly when she goes to bed. According to the books there is no one thing that triggers it.
One day at a time