I had my first case of shingles at age 31. It was a VERY minor case, just a few places across my back. The few things I remember my doc telling me about it was that it's a form of herpes which apparently "lives" in the nervous system. As such, it can easily be triggered by stress. At the time I was extremely stressed out at work which would explain why I got it at such a young age compared to the stereotypical case.
So when I read that your young child had shingles, I was very curious about this.