http://www.medscape.com/viewarticle/780197 (http://www.medscape.com/viewarticle/780197)
Basically, what this boils down to is IgE, IgE, IgE.
If you have a number <2 at diagnosis, that's very good, and if it's >10, that is VERY bad.
If it's in between, you'll be waiting a while, but odds are good that you'll eventually outgrow naturally.