My 7yo has been on prednisone off and on for most of his life. Pros are that it allows him to breathe easily, without wheezing, and it increases his appetite lol. If it's a short term course of pred, I'd go ahead and give it; most of the cons come with long term usage.
Cons - can cause growth retardation with long term use, and many many side effects. http://www.nlm.nih.gov/medlineplus/d...r/a601102.html
has a pretty good list, but as I said, many of the side effects are w/ long term usage.
My ds has asthma and allergies, and when he has a serious attack prednisone can snap him right out of it.