My 7mo old daughter is also on prenisolone.  She was switched at about 4 months of age due to her undersupression with the hydrocortisone.  She is in the 50th % for her weight & 75th% for her height. I was really concrened about the switch at first.  I had heard about the pred. being problematic for her growth.  I discussed this with her Endo at length. 

He showed me the latest research & the concerns with the prednisone & showed me the dose levels that the research was done at that showed growth issues...we worked out on paper how much of the medication that would be for her...then we started her on a 5th of that dose, she is doing great!  I have also seen a collegue of his while our endo was on vacation & he told me that more research is being performed & that prednisone is starting to be used more....I know that it has worked much better for my daughter.  

It sounds like maybe this medication isn’t right for your child, I am just assuming from your post.  Everyone is different, maybe the  circadium rythum dosing of hydrocortisone would work better for your child.  Ask her Endo for help, if the Endo is not willing, or informed enough to be of help....get a new Endo.  Your child deserves only the best!!!

Jess